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<appendix id="release">
 <title>Release Notes</title>

 <sect1 id="release-introduction">
  <title>Introduction</title>

  <para>
   The release notes contain the significant changes in each PostgreSQL
   release, with major features and migration issues often listed at the
   top.  The release notes do not contain changes that affect only a few
   users or changes that are internal and therefore not user-visible.  For
   example, the optimizer is improved in almost every release, but the
   improvements are usually observed by users as simply faster queries.
  </para>

  <para>
   A complete list of changes for each release can be obtained by
   viewing the <link linkend="cvs">CVS</link> logs for each release.  The <ulink
   url="http://archives.postgresql.org/pgsql-committers/">committers email
   list</ulink> contains all source code changes as well.   There is also
   a <ulink url="http://developer.postgresql.org/cvsweb.cgi/pgsql/">web
   interface</ulink> that shows changes to specific files.
   <!-- we need a file containing the CVS logs for each release, and something
   like the SVN web interface that groups commits but has branches -->
  </para>

  <para>
   The name appearing next to each item represents the major developer for
   that item.  Of course all changes involve community discussion and patch
   review so each item is truly a community effort.
  </para>

 </sect1>

 <sect1 id="release-8-3">
  <title>Release 8.3</title>

  <note>
   <title>Release date</title>
   <simpara>2007-12-??</simpara>
   <para>CURRENT AS OF 2007-12-01</>
  </note>

  <sect2>
   <title>Overview</title>

   <para>
    With significant new functionality and performance enhancements,
    this release represents a major leap forward for
    <productname>PostgreSQL</>. This was made possible by a growing
    community that has dramatically accelerated the pace of
    development. This release adds the following major features:
   </para>

   <itemizedlist>

    <listitem>
     <para>
      Full text search is integrated into the core database system
     </para>
    </listitem>

    <listitem>
     <para>
      Support for the SQL/XML standard, including new operators and an
      <type>XML</type> data type
     </para>
    </listitem>

    <listitem>
     <para>
      Enumerated data types (<type>ENUM</type>)
     </para>
    </listitem>

    <listitem>
     <para>
      Arrays of composite types
     </para>
    </listitem>

    <listitem>
     <para>
      Universally Unique Identifier (<type>UUID</>) data type
     </para>
    </listitem>

    <listitem>
     <para>
      Add control over whether <literal>NULL</>s sort first or last
     </para>
    </listitem>

    <listitem>
     <para>
      Updatable cursors
     </para>
    </listitem>

    <listitem>
     <para>
      Server configuration parameters can now be set on a per-function
      basis
     </para>
    </listitem>

    <listitem>
     <para>
      User-defined types can now have type modifiers
     </para>
    </listitem>

    <listitem>
     <para>
      Automatically re-plan cached queries when table
      definitions change or statistics are updated
     </para>
    </listitem>

    <listitem>
     <para>
      Numerous improvements in logging and statistics collection
     </para>
    </listitem>

    <listitem>
     <para>
      Support Security Service Provider Interface (<acronym>SSPI</>) for
      authentication on Windows
     </para>
    </listitem>

    <listitem>
     <para>
      Support multiple concurrent autovacuum processes, and other
      autovacuum improvements
     </para>
    </listitem>

    <listitem>
     <para>
      Allow the whole <productname>PostgreSQL</> distribution to be compiled
      with <productname>Microsoft Visual C++</>
     </para>
    </listitem>

   </itemizedlist>

   <para>
    Major performance improvements are listed below.  Most of
    these enhancements are automatic and do not require user changes or
    tuning:
   </para>

  <itemizedlist>

    <listitem>
     <para>
      Asynchronous commit delays writes to WAL during transaction commit
     </para>
    </listitem>

    <listitem>
     <para>
      Checkpoint writes can be spread over a longer time period to smooth
      the I/O spike during each checkpoint
     </para>
    </listitem>

    <listitem>
     <para>
      Heap-Only Tuples (<acronym>HOT</>) accelerate space reuse for
      most <command>UPDATE</>s
     </para>
    </listitem>

    <listitem>
     <para>
      Just-in-time background writer strategy improves disk write
      efficiency
     </para>
    </listitem>

    <listitem>
     <para>
      Using non-persistent transaction IDs for read-only transactions
      reduces overhead and <command>VACUUM</> requirements
     </para>
    </listitem>

    <listitem>
     <para>
      Per-field and per-row storage overhead has been reduced
     </para>
    </listitem>

    <listitem>
     <para>
      Large sequential scans no longer force out frequently used
      cached pages
     </para>
    </listitem>

    <listitem>
     <para>
      Concurrent large sequential scans can now share disk reads
     </para>
    </listitem>

    <listitem>
     <para>
      <literal>ORDER BY ... LIMIT</> can be done without sorting
     </para>
    </listitem>

   </itemizedlist>

   <para>
    The above items are explained in more detail in the sections below.
   </para>

  </sect2>

  <sect2>
   <title>Migration to Version 8.3</title>

   <para>
    A dump/restore using <application>pg_dump</application> is
    required for those wishing to migrate data from any previous
    release.
   </para>

   <para>
    Observe the following incompatibilities:
   </para>

   <sect3>
    <title>General</title>
    <itemizedlist>

     <listitem>
      <para>
       Non-character data types are no longer automatically cast to
       <type>TEXT</> (Peter, Tom)
      </para>

      <para>
       Previously, if a non-character value was supplied to an operator or
       function that requires <type>text</> input, it was automatically
       cast to <type>text</>, for most (though not all) built-in data types.
       This no longer happens: an explicit cast to <type>text</> is now
       required for all non-character-string types.  For example, these
       expressions formerly worked:

<programlisting>
substr(current_date, 1, 4)
23 LIKE '2%'
</programlisting>

       but will now draw <quote>function does not exist</> and <quote>operator
       does not exist</> errors respectively.  Use an explicit cast instead:

<programlisting>
substr(current_date::text, 1, 4)
23::text LIKE '2%'
</programlisting>

       (Of course, you can use the more verbose <literal>CAST()</> syntax too.)
       The reason for the change is that these automatic casts too often caused
       surprising behavior.  An example is that in previous releases, this
       expression was accepted but did not do what was expected:

<programlisting>
current_date &lt; 2017-11-17
</programlisting>

       This is actually comparing a date to an integer, which should be
       (and now is) rejected &mdash; but in the presence of automatic
       casts both sides were cast to <type>text</> and a textual comparison
       was done, because the <literal>text &lt; text</> operator was able
       to match the expression when no other <literal>&lt;</> operator could.
      </para>

      <para>
       Types <type>char(<replaceable>n</>)</type> and
       <type>varchar(<replaceable>n</>)</type> still cast to <type>text</>
       automatically.  Also, automatic casting to <type>text</> still works for
       inputs to the concatenation (<literal>||</>) operator, so long as least
       one input is a character-string type.
      </para>
     </listitem>

     <listitem>
      <para>
        Full text search features from <filename>contrib/tsearch2</> have
        been moved into the core server, with some minor syntax changes
      </para>

      <para>
       <filename>contrib/tsearch2</> now contains a compatibility
       interface.
      </para>
     </listitem>

     <listitem>
      <para>
       <literal>ARRAY(SELECT ...)</literal>, where the <command>SELECT</>
       returns no rows, now returns an empty array, rather than NULL
       (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       The array type name for a base data type is no longer always the base
       type's name with an underscore prefix
      </para>

      <para>
       The old naming convention is still honored when possible, but
       application code should no longer depend on it. Instead
       use the new <literal>pg_type.typarray</literal> column to
       identify the array data type associated with a given type.
      </para>
     </listitem>

     <listitem>
      <para>
       <literal>ORDER BY ... USING</> <replaceable>operator</> must now
       use a less-than or greater-than <replaceable>operator</> that is
       defined in a btree operator class
      </para>

      <para>
       This restriction was added to prevent inconsistent results.
      </para>
     </listitem>

     <listitem>
      <para>
       <command>SET LOCAL</command> changes now persist until
       the end of the outermost transaction, unless rolled back (Tom)
      </para>

      <para>
       Previously <command>SET LOCAL</command>'s effects were lost
       after subtransaction commit (<command>RELEASE SAVEPOINT</>
       or exit from a PL/pgSQL exception block).
      </para>
     </listitem>

     <listitem>
      <para>
       Commands rejected in transaction blocks are now also rejected in
       multiple-statement query strings (Tom)
      </para>

      <para>
       For example, <literal>"BEGIN; DROP DATABASE; COMMIT"</> will now be
       rejected even if submitted as a single query message.
      </para>
     </listitem>

     <listitem>
      <para>
       <command>ROLLBACK</> outside a transaction block now
       issues <literal>NOTICE</> instead of <literal>WARNING</> (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Prevent <command>NOTIFY</command>/<command>LISTEN</command>/<command>UNLISTEN</command>
       from accepting schema-qualified names (Bruce)
      </para>

      <para>
       Formerly, these commands accepted <literal>schema.relation</> but
       ignored the schema part, which was confusing.
      </para>
     </listitem>

     <listitem>
      <para>
       <command>ALTER SEQUENCE</> no longer affects the sequence's
       <function>currval()</> state (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Foreign keys now must match indexable conditions for
       cross-data-type references (Tom)
      </para>

      <para>
       This improves semantic consistency and helps avoid
       performance problems.
      </para>
     </listitem>

     <listitem>
      <para>
       Restrict object size functions to users who have reasonable
       permissions to view such information (Tom)
      </para>

      <para>
       For example, <function>pg_database_size()</function> now requires
       <literal>CONNECT</> permission, which is granted to everyone by
       default. <function>pg_tablespace_size()</function> requires
       <literal>CREATE</> permission in the tablespace, or is allowed if
       the tablespace is the default tablespace for the database.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove the undocumented <literal>!!=</> (not in) operator (Tom)
      </para>

      <para>
       <literal>NOT IN (SELECT ...)</literal> is the proper way to
       perform this operation.
      </para>
     </listitem>

     <listitem>
      <para>
       Internal hashing functions are now more uniformly-distributed (Tom)
      </para>

      <para>
       If application code was computing and storing hash values using
       internal <productname>PostgreSQL</> hashing functions, the hash
       values must be regenerated.
      </para>
     </listitem>

     <listitem>
      <para>
       C-code conventions for handling variable-length data values
       have changed (Greg Stark, Tom)
      </para>

      <para>
       The new <function>SET_VARSIZE()</> macro <emphasis>must</> be used
       to set the length of generated <type>varlena</> values. Also, it
       might be necessary to expand (<quote>de-TOAST</quote>) input values
       in more cases.
      </para>
     </listitem>

     <listitem>
      <para>
       Continuous archiving no longer reports each successful archive
       operation to the server logs unless <literal>DEBUG</> level is used
       (Simon)
      </para>
     </listitem>

    </itemizedlist>

    </sect3>

    <sect3>
     <title>Configuration Parameters</title>

    <itemizedlist>

     <listitem>
      <para>
       Numerous changes in administrative server parameters
      </para>

      <para>
       <varname>bgwriter_lru_percent</>,
       <varname>bgwriter_all_percent</>,
       <varname>bgwriter_all_maxpages</>,
       <varname>stats_start_collector</>, and
       <varname>stats_reset_on_server_start</> are removed.
       <varname>redirect_stderr</> is renamed to
       <varname>logging_collector</>. 
       <varname>stats_command_string</> is renamed to
       <varname>track_activities</>.
       <varname>stats_block_level</> and <varname>stats_row_level</>
       are merged into <varname>track_counts</>.
       A new boolean configuration parameter, <varname>archive_mode</>,
       controls archiving. Autovacuum's default settings have changed.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <varname>stats_start_collector</varname> parameter (Tom)
      </para>

      <para>
       We now always start the collector process, unless <acronym>UDP</>
       socket creation fails.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <varname>stats_reset_on_server_start</varname> parameter (Tom)
      </para>

      <para>
       This was removed because <function>pg_stat_reset()</function>
       can be used for this purpose.
      </para>
     </listitem>

     <listitem>
      <para>
       Commenting out a parameter in <filename>postgresql.conf</> now
       causes it to revert to its default value (Joachim Wieland)
      </para>

      <para>
       Previously, commenting out an entry left the parameter's value unchanged
       until the next server restart.
      </para>
     </listitem>

    </itemizedlist>

    </sect3>


    <sect3>
     <title>Character Encodings</title>

    <itemizedlist>

     <listitem>
      <para>
       Add more checks for invalidly-encoded data (Andrew)
      </para>

      <para>
       This change plugs some holes that existed in literal backslash
       escape string processing and <command>COPY</command> escape
       processing. Now the de-escaped string is rechecked to see if the
       result created an invalid multi-byte character.
      </para>
     </listitem>

     <listitem>
      <para>
       Disallow database encodings that are inconsistent with the server's
       locale setting (Tom)
      </para>

      <para>
       On most platforms, <literal>C</> locale is the only locale that
       will work with any database encoding.  Other locale settings imply
       a specific encoding and will misbehave if the database encoding
       is something different.  (Typical symptoms include bogus textual
       sort order and wrong results from <function>upper()</> or
       <function>lower()</>.)  The server now rejects attempts to create
       databases that have an incompatible encoding.
      </para>
     </listitem>

     <listitem>
      <para>
       Ensure that <function>chr()</function> cannot create
       invalidly-encoded values (Andrew)
      </para>

      <para>
       In UTF8-encoded databases the argument of <function>chr()</function> is
       now treated as a Unicode code point. In other multi-byte encodings
       <function>chr()</function>'s argument must designate a 7-bit ASCII
       character.  Zero is no longer accepted.
       <function>ascii()</function> has been adjusted to match.
      </para>
     </listitem>

     <listitem>
      <para>
       Adjust <function>convert()</function> behavior to ensure encoding
       validity (Andrew)
      </para>

      <para>
       The two argument form of <function>convert()</function> has been
       removed. The three argument form now takes a <type>bytea</type>
       first argument and returns a <type>bytea</type>. To cover the
       loss of functionality, three new functions have been added:
      </para>

      <itemizedlist>
       <listitem>
        <para>
         <function>convert_from(bytea, name)</function> returns
         <type>text</> &mdash; converts the first argument from the named
         encoding to the database encoding
        </para>
       </listitem>

       <listitem>
        <para>
         <function>convert_to(text, name)</function> returns
         <type>bytea</> &mdash; converts the first argument from the
         database encoding to the named encoding
        </para>
       </listitem>

       <listitem>
        <para>
         <function>length(bytea, name)</function> returns
         <type>integer</> &mdash; gives the length of the first
         argument in characters in the named encoding
        </para>
       </listitem>
      </itemizedlist>
     </listitem>

     <listitem>
      <para>
       Remove <literal>convert(argument USING conversion_name)</literal>
       (Andrew)
      </para>

      <para>
       Its behavior did not match the SQL standard.
      </para>
     </listitem>

     <listitem>
      <para>
       Make JOHAB encoding client-only (Tatsuo)
      </para>

      <para>
       JOHAB is not safe as a server-side encoding.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    Below you will find a detailed account of the
    changes between <productname>PostgreSQL</productname> 8.3 and
    the previous major release.
   </para>

   <sect3>
    <title>Performance</title>
    <itemizedlist>

     <listitem>
      <para>
       Asynchronous commit delays writes to WAL during transaction commit
       (Simon)
      </para>

      <para>
       This feature dramatically increases performance for short data-modifying
       transactions. The disadvantage is that because disk writes are
       delayed, if the operating system crashes before data is written to
       the disk, committed data will be lost. This feature is useful for
       applications that can accept some data loss.  Unlike turning off
       <varname>fsync</varname>, asynchronous commit does not put database
       consistency at risk; the worst case is that after a database or system
       crash the last few reportedly-committed transactions might be missing.
       This feature is enabled by turning off <varname>synchronous_commit</>
       (which can be done per-session or per-transaction, if some transactions
       are critical and others are not).
       <varname>wal_writer_delay</> can be adjusted to control the maximum
       delay before transactions actually reach disk.
      </para>
     </listitem>

     <listitem>
      <para>
       Checkpoint writes can be spread over a longer time period to smooth
       the I/O spike during each checkpoint (Itagaki Takahiro and Heikki
       Linnakangas)
      </para>

      <para>
       Previously all modified buffers were forced to disk as quickly as
       possible during a
       checkpoint, causing an I/O spike that decreased server performance.
       This new approach spreads out disk writes during checkpoints,
       reducing peak I/O usage. (User-requested and shutdown checkpoints
       are still written as quickly as possible.)
      </para>
     </listitem>

     <listitem>
      <para>
       Heap-Only Tuples (<acronym>HOT</>) accelerate space reuse for most
       <command>UPDATE</>s (Pavan Deolasee, with ideas from many others)
      </para>

      <para>
       <command>UPDATE</>s and <command>DELETE</>s leave dead tuples
       behind, as do failed <command>INSERT</>s.  Previously only
       <command>VACUUM</> could reclaim space taken by dead tuples. With
       <acronym>HOT</> dead tuple space can be reclaimed at the time of
       <command>UPDATE</> or <command>INSERT</> if no changes are made to
       indexed columns.  This allows for more consistent performance.
       Also, <acronym>HOT</> avoids adding duplicate index entries.
      </para>
     </listitem>

     <listitem>
      <para>
       Just-in-time background writer strategy improves disk write
       efficiency (Greg Smith, Itagaki Takahiro)
      </para>

      <para>
       This greatly reduces the need for manual tuning of the background
       writer.
      </para>
     </listitem>

     <listitem>
      <para>
       Per-field and per-row storage overhead have been reduced
       (Greg Stark, Heikki Linnakangas)
      </para>

      <para>
       Variable-length data types with data values less than 128 bytes long
       will see a storage decrease of 3 to 6 bytes. For example, two adjacent
       <type>char(1)</type> fields now use 4 bytes instead of 16. Row headers
       are also 4 bytes shorter than before.
      </para>
     </listitem>

     <listitem>
      <para>
       Using non-persistent transaction IDs for read-only transactions
       reduces overhead and <command>VACUUM</> requirements (Florian Pflug)
      </para>

      <para>
       Non-persistent transaction IDs do not increment the global
       transaction counter. Therefore, they reduce the load on
       <structname>pg_clog</> and increase the time between forced
       vacuums to prevent transaction ID wraparound.
       Other performance
       improvements were also made that should improve concurrency.
      </para>
     </listitem>

     <listitem>
      <para>
       Avoid incrementing the command counter after a read-only command (Tom)
      </para>

      <para>
       There was formerly a hard limit of 2<superscript>32</>
       (4 billion) commands per transaction.  Now only commands that
       actually changed the database count, so while this limit still
       exists, it should be significantly less annoying.
      </para>
     </listitem>

     <listitem>
      <para>
       Create a dedicated <acronym>WAL</> writer process to off-load
       work from backends (Simon)
      </para>
     </listitem>

     <listitem>
      <para>
       Skip unnecessary WAL writes for <command>CLUSTER</command> and
       <command>COPY</command> (Simon)
      </para>

      <para>
       Unless WAL archiving is enabled, the system now avoids WAL writes
       for <command>CLUSTER</command> and just <function>fsync()</>s the
       table at the end of the command.  It also does the same for
       <command>COPY</command> if the table was created in the same
       transaction.
      </para>
     </listitem>

     <listitem>
      <para>
       Large sequential scans no longer force out frequently used
       cached pages (Simon, Heikki, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Concurrent large sequential scans can now share disk reads (Jeff Davis)
      </para>

      <para>
       This is accomplished by starting the new sequential scan in the
       middle of the table (where another sequential scan is already
       in-progress) and wrapping around to the beginning to finish.  This
       can affect the order of returned rows in a query that does not
       specify <literal>ORDER BY</>.
      </para>
     </listitem>

     <listitem>
      <para>
       <literal>ORDER BY ... LIMIT</> can be done without sorting
       (Greg Stark)
      </para>

      <para>
       This is done by sequentially scanning the table and tracking just
       the <quote>top N</> candidate rows, rather than performing a
       full sort of the entire table.  This is useful when there is no
       matching index and the <literal>LIMIT</> is not large.
      </para>
     </listitem>

     <listitem>
      <para>
       Put a rate limit on messages sent to the statistics
       collector by backends
       (Tom)
      </para>

      <para>
       This reduces overhead for short transactions, but might sometimes
       increase the delay before statistics are tallied.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve hash join performance for cases with many NULLs (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Speed up operator lookup for cases with non-exact datatype matches (Tom)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Server</title>
    <itemizedlist>

     <listitem>
      <para>
       Autovacuum is now enabled by default (Alvaro)
      </para>

      <para>
       Several changes were made to eliminate disadvantages of having
       autovacuum enabled, thereby justifying the change in default.
       Several other autovacuum parameter defaults were also modified.
      </para>
     </listitem>

     <listitem>
      <para>
       Support multiple concurrent autovacuum processes (Alvaro, Itagaki
       Takahiro)
      </para>

      <para>
       This allows multiple vacuums to run concurrently.  This prevents
       vacuuming of a large table from delaying vacuuming of smaller tables.
      </para>
     </listitem>

     <listitem>
      <para>
       Automatically re-plan cached queries when table
       definitions change or statistics are updated (Tom)
      </para>

      <para>
       Previously PL/PgSQL functions that referenced temporary tables
       would fail if the temporary table was dropped and recreated
       between function invocations, unless <literal>EXECUTE</> was
       used.  This improvement fixes that problem and many related issues.
      </para>
     </listitem>

     <listitem>
      <para>
       Add a <varname>temp_tablespaces</varname> parameter to control
       the tablespaces for temporary tables and files (Jaime Casanova,
       Albert Cervera, Bernd Helmle)
      </para>

      <para>
       This parameter defines a list of tablespaces to be used.  This
       enables spreading the I/O load across multiple tablespaces. A random
       tablespace is chosen each time a temporary object is created.
       Temporary files are no longer stored in per-database
       <filename>pgsql_tmp/</filename> directories but in per-tablespace
       directories.
      </para>
     </listitem>

     <listitem>
      <para>
       Place temporary tables' TOAST tables in special schemas named
       <literal>pg_toast_temp_<replaceable>nnn</></literal> (Tom)
      </para>

      <para>
       This allows low-level code to recognize these tables as temporary,
       which enables various optimizations such as not WAL-logging changes
       and using local rather than shared buffers for access. This also
       fixes a bug wherein backends unexpectedly held open file references
       to temporary TOAST tables.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix problem that a constant flow of new connection requests could
       indefinitely delay the postmaster from completing a shutdown or
       a crash restart (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Guard against a very-low-probability data loss scenario by preventing
       re-use of a deleted table's relfilenode until after the next
       checkpoint (Heikki)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <command>CREATE CONSTRAINT TRIGGER</>
       to convert old-style foreign key trigger definitions into regular
       foreign key constraints (Tom)
      </para>

      <para>
       This will ease porting of foreign key constraints carried forward from
       pre-7.3 databases, if they were never converted using
       <filename>contrib/adddepend</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <literal>DEFAULT NULL</> to override inherited defaults (Tom)
      </para>

      <para>
       <literal>DEFAULT NULL</> was formerly considered a noise phrase, but it
       should (and now does) override non-null defaults that would otherwise
       be inherited from a parent table or domain.
      </para>
     </listitem>

     <listitem>
      <para>
       Add new encodings EUC_JIS_2004 and SHIFT_JIS_2004 (Tatsuo)
      </para>

      <para>
       These new encodings can be converted to and from UTF-8.
      </para>
     </listitem>

     <listitem>
      <para>
       Change server startup log message from <quote>database system is
       ready</quote> to <quote>database system is ready to accept
       connections</quote>, and adjust its timing
      </para>

      <para>
       The message now appears only when the postmaster is really ready
       to accept connections.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Monitoring</title>
    <itemizedlist>

     <listitem>
      <para>
       Add <varname>log_autovacuum_min_duration</varname> parameter to
       support configurable logging of autovacuum activity (Simon, Alvaro)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <varname>log_lock_waits</varname> parameter to log lock waiting
       (Simon)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <varname>log_temp_files</varname> parameter to log temporary
       file usage (Bill Moran)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <varname>log_checkpoints</varname> parameter to improve logging
       of checkpoints (Greg Smith, Heikki)
      </para>
     </listitem>

     <listitem>
      <para>
       <varname>log_line_prefix</varname> now supports
       <literal>%s</literal> and <literal>%c</literal> escapes in all
       processes (Andrew)
      </para>

      <para>
       Previously these escapes worked only for user sessions, not for
       background database processes.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <varname>log_restartpoints</varname> to control logging of
       point-in-time recovery restart points (Simon)
      </para>
     </listitem>

     <listitem>
      <para>
       Last transaction end time is now logged at end of recovery and at
       each logged restart point (Simon)
      </para>
     </listitem>

     <listitem>
      <para>
       Autovacuum now reports its activity start time in
       <literal>pg_stat_activity</literal> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow server log output in comma-separated value (CSV) format (Arul
       Shaji, Greg Smith, Andrew Dunstan)
      </para>

      <para>
       CSV-format log files can easily be loaded into a database table for
       subsequent analysis.
      </para>
     </listitem>

     <listitem>
      <para>
       Use PostgreSQL-supplied timezone support for formatting timestamps
       displayed in the server log (Tom)
      </para>

      <para>
       This avoids Windows-specific problems with localized time zone
       names that are in the wrong encoding. There is a new
       <varname>log_timezone</> parameter that controls the timezone
       used in log messages, independently of the client-visible
       <varname>timezone</> parameter.
      </para>
     </listitem>

     <listitem>
      <para>
       New system view <literal>pg_stat_bgwriter</literal> displays
       statistics about background writer activity (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Add new columns for database-wide tuple statistics to
       <literal>pg_stat_database</literal> (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Add an <literal>xact_start</literal> (transaction start time) column to
       <literal>pg_stat_activity</literal> (Neil)
      </para>

      <para>
       This makes it easier to identify long-running transactions.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>n_live_tuples</> and <literal>n_dead_tuples</> columns
       to <literal>pg_stat_all_tables</literal> and related views (Glen
       Parker)
      </para>
     </listitem>

     <listitem>
      <para>
       Merge <varname>stats_block_level</> and <varname>stats_row_level</>
       parameters into a single parameter <varname>track_counts</>, which
       controls all messages sent to the statistics collector process
       (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Rename <varname>stats_command_string</varname> parameter to
       <varname>track_activities</varname> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix statistical counting of live and dead tuples to recognize that
       committed and aborted transactions have different effects (Tom)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Authentication</title>
    <itemizedlist>

     <listitem>
      <para>
       Support Security Service Provider Interface (<acronym>SSPI</>) for
       authentication on Windows (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Support GSSAPI authentication (Henry Hotz, Magnus)
      </para>

      <para>
       This should be preferred to native Kerberos authentication because
       GSSAPI is an industry standard.
      </para>
     </listitem>

     <listitem>
      <para>
       Support a global SSL configuration file (Victor Wagner)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <varname>ssl_ciphers</> parameter to control accepted SSL ciphers
       (Victor Wagner)
      </para>
     </listitem>

     <listitem>
      <para>
       Add a Kerberos realm parameter, <varname>krb_realm</> (Magnus)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Write-Ahead Log (<acronym>WAL</>) and Continuous Archiving</title>
    <itemizedlist>

     <listitem>
      <para>
       Change the timestamps recorded in transaction WAL records from
       time_t to TimestampTz representation (Tom)
      </para>

      <para>
       This provides sub-second resolution in WAL, which can be useful for
       point-in-time recovery.
      </para>
     </listitem>

     <listitem>
      <para>
       Reduce WAL disk space needed by warm standby servers (Simon)
      </para>
     
      <para>
       This change allows a warm standby server to pass the name of the earliest
       still-needed WAL file to the recovery script, allowing automatic removal
       of no-longer-needed WAL files.  This is done using <literal>%r</> in
       the <varname>restore_command</varname> parameter of
       <filename>recovery.conf</filename>.
      </para>
     </listitem>

     <listitem>
      <para>
       New boolean configuration parameter, <varname>archive_mode</>,
       controls archiving (Simon)
      </para>

      <para>
       Previously setting <varname>archive_command</> to an empty string
       turned off archiving. Now <varname>archive_mode</> turns archiving
       on and off, independently of <varname>archive_command</>. This is
       useful for stopping archiving temporarily.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Queries</title>
    <itemizedlist>

     <listitem>
      <para>
       Full text search is integrated into the core database
       system (Teodor, Oleg)
      </para>

      <para>
       Text search has been improved, moved into the core code, and is now
       installed by default.  <filename>contrib/tsearch2</> now contains
       a compatibility interface.
      </para>
     </listitem>

     <listitem>
      <para>
       Add control over whether <literal>NULL</>s sort first or last (Teodor, Tom)
      </para>

      <para>
       The syntax is <literal>ORDER BY ... NULLS FIRST/LAST</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow per-column ascending/descending (<literal>ASC</>/<literal>DESC</>)
       ordering options for indexes (Teodor, Tom)
      </para>

      <para>
       Previously a query using <literal>ORDER BY</> with mixed
       <literal>ASC</>/<literal>DESC</> specifiers could not fully use
       an index. Now an index can be fully used in such cases if the
       index was created with matching
       <literal>ASC</>/<literal>DESC</> specifications.
       <literal>NULL</> sort order within an index can be controlled, too.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <literal>col IS NULL</> to use an index (Teodor)
      </para>
     </listitem>

     <listitem>
      <para>
       Updatable cursors (Arul Shaji, Tom)
      </para>

      <para>
       This eliminates the need to reference a primary key to
       <command>UPDATE</> or <command>DELETE</> rows returned by a cursor.
       The syntax is <literal>UPDATE/DELETE WHERE CURRENT OF</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <literal>FOR UPDATE</literal> in cursors (Arul Shaji, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Create a general mechanism that supports casts to and from the
       standard string types (<type>TEXT</type>, <type>VARCHAR</type>,
       <type>CHAR</type>) for <emphasis>every</emphasis> datatype, by
       invoking the datatype's I/O functions (Tom)
      </para>

      <para>
       Previously, such casts were available only for types that had
       specialized function(s) for the purpose.
       These new casts are assignment-only in the to-string direction,
       explicit-only in the other direction, and therefore should create no
       surprising behavior.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <literal>UNION</> and related constructs to return a domain
       type, when all inputs are of that domain type (Tom)
      </para>

      <para>
       Formerly, the output would be considered to be of the domain's base
       type.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow limited hashing when using two different data types (Tom)
      </para>

      <para>
       This allows hash joins, hash indexes, hashed subplans, and hash
       aggregation to be used in situations involving cross-data-type
       comparisons, if the data types have compatible hash functions.
       Currently, cross-data-type hashing support exists for
       <type>smallint</type>/<type>integer</type>/<type>bigint</type>,
       and for <type>float4</type>/<type>float8</type>.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve optimizer logic for detecting when variables are equal
       in a <literal>WHERE</> clause (Tom)
      </para>

      <para>
       This allows mergejoins to work with descending sort orders, and
       improves recognition of redundant sort columns.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve performance when planning large inheritance trees in
       cases where most tables are excluded by constraints (Tom)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Object Manipulation</title>
    <itemizedlist>

     <listitem>

      <para>
       Arrays of composite types (David Fetter, Andrew, Tom)
      </para>

      <para>
       In addition to arrays of explicitly-declared composite types,
       arrays of the rowtypes of regular tables and views are now
       supported, except for rowtypes of system catalogs, sequences, and TOAST
       tables.
      </para>

     </listitem>

     <listitem>
      <para>
       Server configuration parameters can now be set on a per-function
       basis (Tom)
      </para>

      <para>
       For example, functions can now set their own
       <varname>search_path</> to prevent unexpected behavior if a
       different <varname>search_path</> exists at run-time.  Security
       definer functions should set <varname>search_path</varname> to
       avoid security loopholes.
      </para>
     </listitem>

     <listitem>
      <para>
       <command>CREATE/ALTER FUNCTION</command> now supports
       <literal>COST</literal> and <literal>ROWS</literal> options (Tom)
      </para>

      <para>
       <literal>COST</literal> allows specification of the cost of a
       function call.  <literal>ROWS</literal> allows specification of
       the average number or rows returned by a set-returning function.
       These values are used by the optimizer in choosing the best plan.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow triggers and rules to be deactivated in groups using a
       configuration parameter, for replication purposes (Jan)
      </para>

      <para>
       This allows replication systems to disable triggers and rewrite
       rules as a group without modifying the system catalogs directly.
       The behavior is controlled by <command>ALTER TABLE</> and a new
       parameter <varname>session_replication_role</varname>.
      </para>
     </listitem>

     <listitem>
      <para>
       User-defined types can now have type modifiers (Teodor, Tom)
      </para>

      <para>
       This allows a user-defined type to take a modifier, like
       <type>ssnum(7)</>.  Previously only built-in
       data types could have modifiers.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Utility Commands</title>
    <itemizedlist>

     <listitem>
      <para>
       Non-superuser database owners now are able to add trusted procedural
       languages to their databases by default (Jeremy Drake)
      </para>

      <para>
       While this is reasonably safe, some administrators might wish to
       revoke the privilege. It is controlled by
       <structname>pg_pltemplate</>.<structfield>tmpldbacreate</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow a session's current parameter setting to be used as the
       default for future sessions (Tom)
      </para>

      <para>
       This is done with <literal>SET ... FROM CURRENT</literal> in
       <command>CREATE/ALTER FUNCTION</command>, <command>ALTER
       DATABASE</command>, or <command>ALTER ROLE</command>.
      </para>
     </listitem>

     <listitem>
      <para>
       Implement new commands <command>DISCARD ALL</command>,
       <command>DISCARD PLANS</command>, <command>DISCARD
       TEMPORARY</command>, <command>CLOSE ALL</command>, and
       <command>DEALLOCATE ALL</command> (Marko Kreen, Neil)
      </para>

      <para>
       These commands simplify resetting a database session to its initial
       state, and are particularly useful for connection-pooling software.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <command>ALTER VIEW ... RENAME TO</command> and <command>ALTER
       SEQUENCE ... RENAME TO</command> (David Fetter, Neil)
      </para>

      <para>
       Previously this could only be done via <command>ALTER TABLE ...
       RENAME TO</command>.
      </para>
     </listitem>

     <listitem>
      <para>
       Implement <command>CREATE TABLE LIKE ...  INCLUDING
       INDEXES</command> (Trevor Hardcastle, Nikhil Sontakke, Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <command>CREATE INDEX CONCURRENTLY</command> to ignore
       transactions in other databases (Simon)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <command>CLUSTER</command> MVCC-safe (Heikki Linnakangas)
      </para>

      <para>
       Formerly, <command>CLUSTER</command> would discard all tuples
       that were committed dead, even if there were still transactions
       that should be able to see them under MVCC visibility rules.
      </para>
     </listitem>

     <listitem>
      <para>
       Add new <command>CLUSTER</command> syntax: <literal>CLUSTER
       <replaceable>table</> USING <replaceable>index</></literal>
       (Holger Schurig)
     </para>

      <para>
       The old <command>CLUSTER</command> syntax is still supported, but
       the new form is considered more logical.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <command>EXPLAIN</command> so it can show complex plans
       more accurately (Tom)
      </para>

      <para>
       References to subplan outputs are now always shown correctly,
       instead of using <literal>?column<replaceable>N</>?</literal>
       for complicated cases.
      </para>
     </listitem>

     <listitem>
      <para>
       Make <command>CREATE/DROP/RENAME DATABASE</> wait briefly for
       conflicting backends to exit before failing (Tom)
      </para>

      <para>
       This increases the likelihood that these commands will succeed.
      </para>
     </listitem>

     <listitem>
      <para>
       Limit the amount of information reported when a user is dropped
       (Alvaro)
      </para>

      <para>
       Previously, dropping (or attempting to drop) a user who owned many
       objects could result in large <literal>NOTICE</literal> or
       <literal>ERROR</literal> messages listing all these objects; this
       caused problems for some client applications.  The length of the
       message is now limited, although a full list is still sent to the
       server log.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Data Types</title>
    <itemizedlist>

     <listitem>
      <para>
       Support for the SQL/XML standard, including new operators and an
       <type>XML</type> data type (Nikolay Samokhvalov, Pavel Stehule, Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Enumerated data types (<type>ENUM</type>) (Tom Dunstan)
      </para>

      <para>
       This feature provides convenient support for fields that have a
       small, fixed set of allowed values.  An example of creating an
       <literal>ENUM</> type is
       <literal>CREATE TYPE mood AS ENUM ('sad', 'ok', 'happy')</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Universally Unique Identifier (<type>UUID</>) data type (Gevik
       Babakhani, Neil)
      </para>

      <para>
       This closely matches <acronym>RFC</> 4122.
      </para>
     </listitem>

     <listitem>
      <para>
       Widen the <type>MONEY</type> data type to 64 bits (D'Arcy Cain)
      </para>

      <para>
       This greatly increases the range of supported <type>MONEY</>
       values.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <type>float4</type>/<type>float8</type> to handle
       <literal>Infinity</> and <literal>NAN</> (Not A Number)
       consistently (Bruce)
      </para>

      <para>
       The code formerly was not consistent about distinguishing
       <literal>Infinity</> from overflow conditions.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow leading and trailing whitespace during input of
       <type>boolean</type> values (Neil)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Functions</title>
    <itemizedlist>

     <listitem>
      <para>
       Add new regular expression functions
       <function>regexp_matches()</function>,
       <function>regexp_split_to_array()</function>, and
       <function>regexp_split_to_table()</function> (Jeremy Drake, Neil)
      </para>

      <para>
       These functions provide extraction of regular expression
       subexpressions and allow splitting a string using a POSIX regular
       expression.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>lo_truncate()</function> for large object truncation
       (Kris Jurka)
      </para>
     </listitem>

     <listitem>
      <para>
       Implement <function>width_bucket()</function> for the <type>float8</>
       data type (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>pg_stat_clear_snapshot()</function> to discard
       statistics snapshots collected during the current transaction
       (Tom)
      </para>

      <para>
       The first request for statistics in a transaction takes a statistics
       snapshot that does not change during the transaction.  This function
       allows the snapshot to be discarded and a new snapshot loaded during
       the next statistics query. This is particularly useful for PL/PgSQL
       functions, which are confined to a single transaction.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>isodow</> option to <function>EXTRACT()</> and
       <function>date_part()</> (Bruce)
      </para>

      <para>
       This returns the day of the week, with Sunday as seven.
       (<literal>dow</> returns Sunday as zero.)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>ID</> (ISO day of week) and <literal>IDDD</> (ISO
       day of year) format codes for <function>to_char()</>,
       <function>to_date()</>, and <function>to_timestamp()</> (Brendan
       Jurd)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <function>to_timestamp()</> and <function>to_date()</>
       assume <literal>TM</literal> (trim) option for potentially
       variable-width fields (Bruce)
      </para>

      <para>
       This matches <productname>Oracle</>'s behavior.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix off-by-one conversion error in
       <function>to_date()</function>/<function>to_timestamp()</function>
       <literal>D</> (non-ISO day of week) fields (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <function>setseed()</function> return void, rather than a
       useless integer value (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Add a hash function for <type>NUMERIC</type> (Neil)
      </para>

      <para>
       This allows hash indexes and hash-based plans to be used with
       <type>NUMERIC</type> columns.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve efficiency of
       <literal>LIKE</literal>/<literal>ILIKE</literal>, especially for
       multi-byte character sets like UTF-8 (Andrew, Itagaki Takahiro)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <function>currtid()</function> functions require
       <literal>SELECT</literal> privileges on the target table (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add several <function>txid_*()</function> functions to query
       active transaction IDs (Jan)
      </para>

      <para>
       This is useful for various replication solutions.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>PL/PgSQL Server-Side Language</title>
    <itemizedlist>

     <listitem>
      <para>
       Add scrollable cursor support, including directional control in
       <command>FETCH</command> (Pavel Stehule)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <literal>IN</literal> as an alternative to
       <literal>FROM</literal> in PL/PgSQL's <command>FETCH</command>
       statement, for consistency with the backend's
       <command>FETCH</command> command (Pavel Stehule)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <command>MOVE</command> to PL/PgSQL (Magnus, Pavel Stehule,
       Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Implement <command>RETURN QUERY</command> (Pavel Stehule, Neil)
      </para>

      <para>
       This adds convenient syntax for PL/PgSQL set-returning functions
       that want to return the result of a query.  <command>RETURN QUERY</>
       is easier and more efficient than a loop
       around <command>RETURN NEXT</command>. 
      </para>
     </listitem>

     <listitem>
      <para>
       Allow function parameter names to be qualified with the
       function's name (Tom)
      </para>

      <para>
       For example, <literal>myfunc.myvar</>. This is particularly
       useful for specifying variables in a query where the variable
       name might match a column name.
      </para>
     </listitem>

     <listitem>
      <para>
       Make qualification of variables with block labels work properly (Tom)
      </para>

      <para>
       Formerly, outer-level block labels could unexpectedly interfere with
       recognition of inner-level record or row references.
      </para>
     </listitem>

     <listitem>
      <para>
       Tighten requirements for <literal>FOR</literal> loop
       <literal>STEP</> values (Tom)
      </para>

      <para>
       Prevent non-positive <literal>STEP</> values, and handle
       loop overflows.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve accuracy when reporting syntax error locations (Tom)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Other Server-Side Languages</title>
    <itemizedlist>

     <listitem>
      <para>
       Allow type-name arguments to PL/Perl
       <function>spi_prepare()</function> to be data type aliases in
       addition to names found in <literal>pg_type</literal> (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow type-name arguments to PL/Python 
       <function>plpy.prepare()</function> to be data type aliases in
       addition to names found in <literal>pg_type</literal> (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow type-name arguments to PL/Tcl <function>spi_prepare</> to 
       be data type aliases in addition to names found in
       <literal>pg_type</literal> (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Enable PL/PythonU to compile on Python 2.5 (Marko Kreen)
      </para>
     </listitem>

     <listitem>
      <para>
       Support a true PL/Python boolean type in compatible Python versions
       (Python 2.3 and later) (Marko Kreen)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix PL/Tcl problems with thread-enabled <filename>libtcl</> spawning
       multiple threads within the backend (Steve Marshall, Paul Bayer,
       Doug Knight)
      </para>

      <para>
       This caused all sorts of unpleasantness.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title><link linkend="APP-PSQL"><application>psql</></link></title>
    <itemizedlist>

     <listitem>
      <para>
       List disabled triggers separately in <literal>\d</literal> output
       (Brendan Jurd)
      </para>
     </listitem>

     <listitem>
      <para>
       In <literal>\d</literal> patterns, always match <literal>$</literal>
       literally (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Show aggregate return types in <literal>\da</literal> output
       (Greg Sabino Mullane)
      </para>
     </listitem>

     <listitem>
      <para>
       Add the function's volatility status to the output of
       <literal>\df+</literal> (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>\prompt</literal> capability (Chad Wagner)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <literal>\pset</literal>, <literal>\t</literal>, and
       <literal>\x</literal> to specify <literal>on</> or <literal>off</>,
       rather than just toggling (Chad Wagner)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>\sleep</> capability (Jan)
      </para>
     </listitem>

     <listitem>
      <para>
       Enable <literal>\timing</> output for <literal>\copy</> (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve <literal>\timing</literal> resolution on Windows
       (Itagaki Takahiro)
      </para>
     </listitem>

     <listitem>
      <para>
       Flush <literal>\o</> output after each backslash command (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Correctly detect and report errors while reading a <literal>-f</>
       input file (Peter)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title><link linkend="APP-PGDUMP"><application>pg_dump</></link></title>
    <itemizedlist>

     <listitem>
      <para>
       Add <literal>--tablespaces-only</> and <literal>--roles-only</>
       options to <application>pg_dumpall</application> (Dave Page)
      </para>
     </listitem>

     <listitem>
      <para>
       Add an output file option to
       <application>pg_dumpall</application> (Dave Page)
      </para>

      <para>
       This is primarily useful on Windows, where output redirection of
       child <application>pg_dump</application> processes does not work.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <application>pg_dumpall</> to accept an initial-connection
       database name rather than the default
       <literal>template1</literal> (Dave Page)
      </para>
     </listitem>

     <listitem>
      <para>
       In <literal>-n</> and <literal>-t</> switches, always match
       <literal>$</literal> literally (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve performance when a database has thousands of objects (Tom)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Other Client Applications</title>
    <itemizedlist>

     <listitem>
      <para>
       In <application>initdb</>, allow the location of the
       <filename>pg_xlog</filename> directory to be specified
       (Euler Taveira de Oliveira)
      </para>
     </listitem>

     <listitem>
      <para>
       Enable server core dump generation in <application>pg_regress</>
       on supported operating systems (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Add a <literal>-t</> (timeout) parameter to <application>pg_ctl</>
       (Bruce)
      </para>

      <para>
       This controls how long <application>pg_ctl</> will wait when waiting
       for server startup or shutdown.  Formerly the timeout was hard-wired
       as 60 seconds.
      </para>
     </listitem>

     <listitem>
      <para>
       Add a <application>pg_ctl</> option to control generation
       of server core dumps (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow Control-C to cancel <application>clusterdb</>,
       <application>reindexdb</>, and <application>vacuumdb</> (Itagaki
       Takahiro, Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Suppress command tag output for <application>createdb</>,
       <application>createuser</>, <application>dropdb</>, and
       <application>dropuser</> (Peter)
      </para>

      <para>
       The <literal>--quiet</> option is ignored and will be removed in 8.4.
       Progress messages when acting on all databases now go to stdout
       instead of stderr because they are not actually errors.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title><link linkend="libpq"><application>libpq</></link></title>
    <itemizedlist>

     <listitem>
      <para>
       Interpret the <literal>dbName</> parameter of
       <function>PQsetdbLogin()</> as a <literal>conninfo</> string if
       it contains an equals sign (Andrew)
      </para>

      <para>
       This allows use of <literal>conninfo</> strings in client
       programs that still use <literal>PQsetdbLogin()</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Support a global <acronym>SSL</> configuration file (Victor
       Wagner)
      </para>
     </listitem>

     <listitem>
      <para>
       Add environment variable <varname>PGSSLKEY</> to control
       <acronym>SSL</> hardware keys (Victor Wagner)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>lo_truncate()</function> for large object
       truncation (Kris Jurka)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>PQconnectionNeedsPassword()</function> that returns
       true if the server required a password but none was supplied
       (Joe Conway, Tom)
      </para>

      <para>
       If this returns true after a failed connection attempt, a client
       application should prompt the user for a password.  In the past
       applications have had to check for a specific error message string to
       decide whether a password is needed; that approach is now
       deprecated.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>PQconnectionUsedPassword()</function> that returns
       true if the supplied password was actually used
       (Joe Conway, Tom)
      </para>

      <para>
       This is useful in some security contexts where it is important
       to know whether a user-supplied password is actually valid.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title><link linkend="ecpg"><application>ecpg</></link></title>
    <itemizedlist>

     <listitem>
      <para>
       Use V3 frontend/backend protocol (Michael)
      </para>

      <para>
       This adds support for server-side prepared statements.
      </para>
     </listitem>

     <listitem>
      <para>
       Use native threads, instead of pthreads, on Windows (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve thread-safety of ecpglib (Itagaki Takahiro)
      </para>
     </listitem>

     <listitem>
      <para>
       Make the ecpg libraries export only necessary API symbols (Michael)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title><application>Windows</> Port</title>
    <itemizedlist>

     <listitem>
      <para>
       Allow the whole <productname>PostgreSQL</> distribution to be compiled
       with <productname>Microsoft Visual C++</> (Magnus and others)
      </para>

      <para>
       This allows Windows-based developers to use familiar development
       and debugging tools.
       Windows executables made with Visual C++ might also have better
       stability and performance than those made with other tool sets.
       The client-only Visual C++ build scripts have been removed.
      </para>
     </listitem>

     <listitem>
      <para>
       Drastically reduce postmaster's memory usage when it has many child
       processes (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow regression tests to be started by an administrative
       user (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Add native shared memory implementation (Magnus)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Server Programming Interface (<acronym>SPI</>)</title>
    <itemizedlist>

     <listitem>
      <para>
       Add cursor-related functionality in SPI (Pavel Stehule)
      </para>

      <para>
       Allow access to the cursor-related planning options, and add
       <command>FETCH</>/<command>MOVE</> routines.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow execution of cursor commands through
       <function>SPI_execute</function> (Tom)
      </para>

      <para>
       The macro <literal>SPI_ERROR_CURSOR</> still exists but will
       never be returned.
      </para>
     </listitem>

     <listitem>
      <para>
       SPI plan pointers are now declared as <literal>SPIPlanPtr</> instead of
       <literal>void *</> (Tom)
      </para>

      <para>
       This does not break application code, but switching is
       recommended to help catch simple programming mistakes.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Build Options</title>
    <itemizedlist>

     <listitem>
      <para>
       Add <application>configure</> option <literal>--enable-profiling</>
       to enable code profiling (works only with <application>gcc</>)
       (Korry Douglas and Nikhil Sontakke)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <application>configure</> option <literal>--with-system-tzdata</>
       to use the operating system's time zone database (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <acronym>PGXS</> so extensions can be built against PostgreSQL
       installations whose <application>pg_config</> program does not
       appear first in the <varname>PATH</> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Support <command>gmake draft</command> when building the
       <acronym>SGML</> documentation (Bruce)
      </para>

      <para>
       Unless <literal>draft</> is used, the documentation build will
       now be repeated if necessary to ensure the index is up-to-date.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Source Code</title>
    <itemizedlist>

     <listitem>
      <para>
       Rename macro <literal>DLLIMPORT</> to <literal>PGDLLIMPORT</> to
       avoid conflicting with third party includes (like Tcl) that
       define <literal>DLLIMPORT</> (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Create <quote>operator families</quote> to improve planning of
       queries involving cross-data-type comparisons (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Update GIN <function>extractQuery()</> API to allow signalling
       that nothing can satisfy the query (Teodor)
      </para>
     </listitem>

     <listitem>
      <para>
       Move <literal>NAMEDATALEN</> definition from
       <filename>postgres_ext.h</> to <filename>pg_config_manual.h</>
       (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Provide <function>strlcpy()</function> and
       <function>strlcat()</function> on all platforms, and replace
       error-prone uses of <function>strncpy()</function>,
       <function>strncat()</function>, etc (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Create hooks to let an external plugin monitor (or even replace) the
       planner and create plans for hypothetical situations (Gurjeet
       Singh, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Create a function variable <literal>join_search_hook</> to let plugins
       override the join search order portion of the planner (Julius
       Stroffek)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>tas()</> support for Renesas' M32R processor
       (Kazuhiro Inaoka)
      </para>
     </listitem>

     <listitem>
      <para>
       <function>quote_identifier()</function> and
       <application>pg_dump</application> no longer quote keywords that are
       unreserved according to the grammar (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Change the on-disk representation of the <type>NUMERIC</type>
       data type so that the <structfield>sign_dscale</> word comes
       before the weight (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Use <acronym>SYSV</> semaphores rather than POSIX on Darwin
       &gt;= 6.0, i.e., OS X 10.2 and up (Chris Marcellino)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link linkend="acronyms">acronym</link> and <link
       linkend="creating-cluster-nfs">NFS</link> documentation
       sections (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       "Postgres" is now documented as an accepted alias for
       "PostgreSQL" (Peter)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Contrib</title>
    <itemizedlist>

     <listitem>
      <para>
       Move <filename>contrib</> <filename>README</> content into the
       main <productname>PostgreSQL</> documentation (Albert Cervera i
       Areny)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <filename>contrib/pageinspect</filename> module for low-level
       page inspection (Simon, Heikki)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <filename>contrib/pg_standby</filename> module for controlling
       warm standby operation (Simon)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <filename>contrib/uuid-ossp</filename> module for generating
       <type>UUID</> values using the OSSP UUID library (Peter)
      </para>

      <para>
       Use <application>configure</>
       <literal>--with-ossp-uuid</literal> to activate. This takes
       advantage of the new <type>UUID</type> builtin type.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <filename>contrib/dict_int</filename>,
       <filename>contrib/dict_xsyn</filename>, and
       <filename>contrib/test_parser</filename> modules to provide
       sample add-on text search dictionary templates and parsers
       (Sergey Karpov)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <application>contrib/pgbench</> to set the fillfactor (Pavan
       Deolasee)
      </para>
     </listitem>

     <listitem>
      <para>
       Add timestamps to <application>contrib/pgbench</> <literal>-l</>
       (Greg Smith)
      </para>
     </listitem>

     <listitem>
      <para>
       Add usage count statistics to
       <filename>contrib/pgbuffercache</filename> (Greg Smith)
      </para>
     </listitem>

     <listitem>
      <para>
       Add GIN support for <filename>contrib/hstore</> (Teodor)
      </para>
     </listitem>

     <listitem>
      <para>
       Add GIN support for <filename>contrib/pg_trgm</> (Guillaume Smet, Teodor)
      </para>
     </listitem>

     <listitem>
      <para>
       Update OS/X startup scripts in
       <filename>contrib/start-scripts</filename> (Mark Cotner, David
       Fetter)
      </para>
     </listitem>

     <listitem>
      <para>
       Restrict <function>pgrowlocks()</function> and
       <function>dblink_get_pkey()</function> to users who have
       <literal>SELECT</literal> privilege on the target table (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Restrict <filename>contrib/pgstattuple</filename> functions to
       superusers (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       <filename>contrib/xml2</filename> is deprecated and planned for
       removal in 8.4 (Peter)
      </para>

      <para>
       The new XML support in core PostgreSQL supersedes this module.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>
  </sect2>
 </sect1>

 <sect1 id="release-8-2-5">
  <title>Release 8.2.5</title>

  <note>
  <title>Release date</title>
  <simpara>2007-09-17</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.2.4.
  </para>

  <sect2>
   <title>Migration to Version 8.2.5</title>

   <para>
    A dump/restore is not required for those running 8.2.X.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Prevent index corruption when a transaction inserts rows and
      then aborts close to the end of a concurrent <command>VACUUM</>
      on the same table (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <literal>ALTER DOMAIN ADD CONSTRAINT</> for cases involving
      domains over domains (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Make <command>CREATE DOMAIN ... DEFAULT NULL</> work properly (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix some planner problems with outer joins, notably poor
      size estimation for <literal>t1 LEFT JOIN t2 WHERE t2.col IS NULL</>
      (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Allow the <type>interval</> data type to accept input consisting only of
      milliseconds or microseconds (Neil)
     </para>
    </listitem>

    <listitem>
     <para>
      Allow timezone name to appear before the year in <type>timestamp</> input (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fixes for <acronym>GIN</> indexes used by <filename>/contrib/tsearch2</> (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Speed up rtree index insertion (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix excessive logging of <acronym>SSL</> error messages (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix logging so that log messages are never interleaved when using
      the syslogger process (Andrew)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix crash when <varname>log_min_error_statement</> logging runs out
      of memory (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix incorrect handling of some foreign-key corner cases (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <function>stddev_pop(numeric)</> and <function>var_pop(numeric)</> (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Prevent <command>REINDEX</> and <command>CLUSTER</> from failing
      due to attempting to process temporary tables of other sessions (Alvaro)
     </para>
    </listitem>

    <listitem>
     <para>
      Update the time zone database rules, particularly New Zealand's upcoming changes (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Windows socket and semaphore improvements (Magnus)
     </para>
    </listitem>

    <listitem>
     <para>
      Make <command>pg_ctl -w</> work properly in Windows service mode (Dave Page)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix memory allocation bug when using <application>MIT Kerberos</> on Windows (Magnus)
     </para>
    </listitem>

    <listitem>
     <para>
      Suppress timezone name (<literal>%Z</>) in log timestamps on Windows
      because of possible encoding mismatches (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Require non-superusers who use <filename>/contrib/dblink</> to use only
      password authentication, as a security measure (Joe)
     </para>
    </listitem>

    <listitem>
     <para>
      Restrict <filename>/contrib/pgstattuple</> functions to superusers, for security reasons (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Do not let <filename>/contrib/intarray</> try to make its GIN opclass
      the default (this caused problems at dump/restore) (Tom)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-2-4">
  <title>Release 8.2.4</title>

  <note>
  <title>Release date</title>
  <simpara>2007-04-23</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.2.3,
   including a security fix.
  </para>

  <sect2>
   <title>Migration to Version 8.2.4</title>

   <para>
    A dump/restore is not required for those running 8.2.X.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Support explicit placement of the temporary-table schema within
      <varname>search_path</>, and disable searching it for functions
      and operators (Tom)
     </para>

     <para>
      This is needed to allow a security-definer function to set a
      truly secure value of <varname>search_path</>.  Without it,
      an unprivileged SQL user can use temporary objects to execute code
      with the privileges of the security-definer function (CVE-2007-2138).
      See <command>CREATE FUNCTION</> for more information.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <varname>shared_preload_libraries</> for Windows
      by forcing reload in each backend (Korry Douglas)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <function>to_char()</> so it properly upper/lower cases localized day or month
      names (Pavel Stehule)
     </para>
    </listitem>

    <listitem>
     <para>
      <filename>/contrib/tsearch2</> crash fixes (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Require <command>COMMIT PREPARED</> to be executed in the same
      database as the transaction was prepared in (Heikki)
     </para>
    </listitem>

    <listitem>
     <para>
      Allow <command>pg_dump</> to do binary backups larger than two gigabytes
      on Windows (Magnus)
     </para>
    </listitem>

    <listitem>
     <para>
      New traditional (Taiwan) Chinese <acronym>FAQ</> (Zhou Daojing)
     </para>
    </listitem>

    <listitem>
     <para>
      Prevent the statistics collector from writing to disk too frequently (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix potential-data-corruption bug in how <command>VACUUM FULL</> handles
      <command>UPDATE</> chains (Tom, Pavan Deolasee)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix bug in domains that use array types (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <command>pg_dump</> so it can dump a serial column's sequence
      using <option>-t</> when not also dumping the owning table
      (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Planner fixes, including improving outer join and bitmap scan
      selection logic (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible wrong answers or crash when a PL/pgSQL function tries
      to <literal>RETURN</> from within an <literal>EXCEPTION</> block
      (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix PANIC during enlargement of a hash index (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix POSIX-style timezone specs to follow new USA DST rules (Tom)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-2-3">
  <title>Release 8.2.3</title>

  <note>
  <title>Release date</title>
  <simpara>2007-02-07</simpara>
  </note>

  <para>
   This release contains two fixes from 8.2.2.
  </para>

  <sect2>
   <title>Migration to Version 8.2.3</title>

   <para>
    A dump/restore is not required for those running 8.2.X.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Remove overly-restrictive check for type length in constraints and
      functional indexes(Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix optimization so MIN/MAX in subqueries can again use indexes (Tom)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-2-2">
  <title>Release 8.2.2</title>

  <note>
  <title>Release date</title>
  <simpara>2007-02-05</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.2.1, including
   a security fix.
  </para>

  <sect2>
   <title>Migration to Version 8.2.2</title>

   <para>
    A dump/restore is not required for those running 8.2.X.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Remove security vulnerabilities that allowed connected users
      to read backend memory (Tom)
     </para>

     <para>
      The vulnerabilities involve suppressing the normal check that a SQL
      function returns the data type it's declared to, and changing the
      data type of a table column (CVE-2007-0555, CVE-2007-0556).  These
      errors can easily be exploited to cause a backend crash, and in
      principle might be used to read database content that the user
      should not be able to access.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix not-so-rare-anymore bug wherein btree index page splits could fail
      due to choosing an infeasible split point (Heikki Linnakangas)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix Borland C compile scripts (L Bayuk)
     </para>
    </listitem>

    <listitem>
     <para>
      Properly handle <function>to_char('CC')</> for years ending in
      <literal>00</> (Tom)
     </para>

     <para>
      Year 2000 is in the twentieth century, not the twenty-first.
     </para>
    </listitem>

    <listitem>
     <para>
      <filename>/contrib/tsearch2</> localization improvements (Tatsuo, Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix incorrect permission check in
      <literal>information_schema.key_column_usage</> view (Tom)
     </para>
 
     <para>
      The symptom is <quote>relation with OID nnnnn does not exist</> errors.
      To get this fix without using <command>initdb</>, use <command>CREATE OR
      REPLACE VIEW</> to install the corrected definition found in
      <filename>share/information_schema.sql</>.  Note you will need to do
      this in each database.
     </para>
    </listitem>

    <listitem>
     <para>
      Improve <command>VACUUM</> performance for databases with many tables (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix for rare Assert() crash triggered by <literal>UNION</> (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix potentially incorrect results from index searches using
      <literal>ROW</> inequality conditions (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Tighten security of multi-byte character processing for UTF8 sequences
      over three bytes long (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix bogus <quote>permission denied</> failures occurring on Windows
      due to attempts to fsync already-deleted files (Magnus, Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix bug that could cause the statistics collector
      to hang on Windows (Magnus)
     </para>

     <para>
      This would in turn lead to autovacuum not working.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible crashes when an already-in-use PL/pgSQL function is
      updated (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Improve PL/pgSQL handling of domain types (Sergiy Vyshnevetskiy, Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible errors in processing PL/pgSQL exception blocks (Tom)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-2-1">
  <title>Release 8.2.1</title>

  <note>
  <title>Release date</title>
  <simpara>2007-01-08</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.2.
  </para>

  <sect2>
   <title>Migration to Version 8.2.1</title>

   <para>
    A dump/restore is not required for those running 8.2.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Fix crash with <literal>SELECT</> ... <literal>LIMIT ALL</> (also
      <literal>LIMIT NULL</>) (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      <filename>Several /contrib/tsearch2</> fixes (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      On Windows, make log messages coming from the operating system use
      <acronym>ASCII</> encoding (Hiroshi Saito)
     </para>

     <para>
      This fixes a conversion problem when there is a mismatch between
      the encoding of the operating system and database server.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix Windows linking of <application>pg_dump</> using
      <filename>win32.mak</>
      (Hiroshi Saito)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix planner mistakes for outer join queries (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix several problems in queries involving sub-SELECTs (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix potential crash in SPI during subtransaction abort (Tom)
     </para>

     <para>
      This affects all PL functions since they all use SPI.
     </para>
    </listitem>

    <listitem>
     <para>
      Improve build speed of <acronym>PDF</> documentation (Peter)
     </para>
    </listitem>

    <listitem>
     <para>
      Re-add <acronym>JST</> (Japan) timezone abbreviation (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Improve optimization decisions related to index scans (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Have <application>psql</> print multi-byte combining characters as
      before, rather than output as <literal>\u</> (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Improve index usage of regular expressions that use parentheses (Tom)
     </para>

     <para>
      This improves <application>psql</> <literal>\d</> performance also.
     </para>
    </listitem>

    <listitem>
     <para>
      Make <application>pg_dumpall</> assume that databases have public
      <literal>CONNECT</> privilege, when dumping from a pre-8.2 server (Tom)
     </para>

     <para>
      This preserves the previous behavior that anyone can connect to a
      database if allowed by <filename>pg_hba.conf</>.
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-2">
  <title>Release 8.2</title>

  <note>
   <title>Release date</title>
   <simpara>2006-12-05</simpara>
  </note>

  <sect2>
   <title>Overview</title>

   <para>
    This release adds many functionality and performance improvements that
    were requested by users, including:

   <itemizedlist>

     <listitem>
      <para>
       Query language enhancements including <command>INSERT/UPDATE/DELETE
       RETURNING</command>, multirow <literal>VALUES</literal> lists, and
       optional target-table alias in
       <command>UPDATE</>/<command>DELETE</command>
      </para>
     </listitem>

     <listitem>
      <para>
       Index creation without blocking concurrent
       <command>INSERT</>/<command>UPDATE</>/<command>DELETE</>
       operations
      </para>
     </listitem>

     <listitem>
      <para>
       Many query optimization improvements, including support for
       reordering outer joins
      </para>
     </listitem>

     <listitem>
      <para>
       Improved sorting performance with lower memory usage
      </para>
     </listitem>

     <listitem>
      <para>
       More efficient locking with better concurrency
      </para>
     </listitem>

     <listitem>
      <para>
       More efficient vacuuming
      </para>
     </listitem>

     <listitem>
      <para>
       Easier administration of warm standby servers
      </para>
     </listitem>

     <listitem>
      <para>
       New <literal>FILLFACTOR</literal> support for tables and indexes
      </para>
     </listitem>

     <listitem>
      <para>
       Monitoring, logging, and performance tuning additions
      </para>
     </listitem>

     <listitem>
      <para>
       More control over creating and dropping objects
      </para>
     </listitem>

     <listitem>
      <para>
       Table inheritance relationships can be defined
       for and removed from pre-existing tables
      </para>
     </listitem>

     <listitem>
      <para>
       <command>COPY TO</command> can copy the output of an arbitrary
       <command>SELECT</command> statement
      </para>
     </listitem>

     <listitem>
      <para>
       Array improvements, including nulls in arrays
      </para>
     </listitem>

     <listitem>
      <para>
       Aggregate-function improvements, including multiple-input
       aggregates and SQL:2003 statistical functions
      </para>
     </listitem>

     <listitem>
      <para>
       Many <filename>contrib/</filename> improvements
      </para>
     </listitem>

    </itemizedlist>

   </para>

  </sect2>

  <sect2>
   <title>Migration to Version 8.2</title>

   <para>
    A dump/restore using <application>pg_dump</application> is
    required for those wishing to migrate data from any previous
    release.
   </para>

   <para>
    Observe the following incompatibilities:
   </para>

   <itemizedlist>

     <listitem>
      <para>
       Set <link
       linkend="guc-escape-string-warning"><varname>escape_string_warning</></link>
       to <literal>on</> by default (Bruce)
      </para>

      <para>
       This issues a warning if backslash escapes are used in
       <link linkend="sql-syntax-strings">non-escape (non-<literal>E''</>)
       strings</link>.
      </para>
     </listitem>

     <listitem>
      <para>
       Change the <link linkend="sql-syntax-row-constructors">row
       constructor syntax</link> (<literal>ROW(...)</>) so that
       list elements <literal>foo.*</> will be expanded to a list
       of their member fields, rather than creating a nested
       row type field as formerly (Tom)
      </para>

      <para>
       The new behavior is substantially more useful since it
       allows, for example, triggers to check for data changes
       with <literal>IF row(new.*) IS DISTINCT FROM row(old.*)</>.
       The old behavior is still available by omitting <literal>.*</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Make <link linkend="row-wise-comparison">row comparisons</link>
       follow <acronym>SQL</> standard semantics and allow them
       to be used in index scans (Tom)
      </para>

      <para>
       Previously, row = and &lt;&gt; comparisons followed the
       standard but &lt; &lt;= &gt; &gt;= did not.  A row comparison
       can now be used as an index constraint for a multicolumn
       index matching the row value.
      </para>
     </listitem>

     <listitem>
      <para>
       Make <link linkend="functions-comparison">row <literal>IS <optional>NOT</> NULL</literal></link>
       tests follow <acronym>SQL</> standard semantics (Tom)
      </para>

      <para>
       The former behavior conformed to the standard for simple cases
       with <literal>IS NULL</>, but <literal>IS NOT NULL</> would return
       true if any row field was non-null, whereas the standard says it
       should return true only when all fields are non-null.
      </para>
     </listitem>

     <listitem>
      <para>
       Make <link linkend="SQL-SET-CONSTRAINTS"><command>SET
       CONSTRAINT</></link> affect only one constraint (Kris Jurka)
      </para>

      <para>
       In previous releases, <command>SET CONSTRAINT</> modified
       all constraints with a matching name.  In this release,
       the schema search path is used to modify only the first
       matching constraint.  A schema specification is also
       supported.  This more nearly conforms to the SQL standard.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <literal>RULE</> permission for tables, for security reasons
       (Tom)
      </para>

      <para>
       As of this release, only a table's owner can create or modify
       rules for the table.  For backwards compatibility,
       <command>GRANT</>/<command>REVOKE RULE</> is still accepted,
       but it does nothing.
      </para>
     </listitem>

     <listitem>
      <para>
       Array comparison improvements (Tom)
      </para>

      <para>
       Now array dimensions are also compared.
      </para>
     </listitem>

     <listitem>
      <para>
       Change <link linkend="functions-array">array concatenation</link>
       to match documented behavior (Tom)
      </para>

      <para>
       This changes the previous behavior where concatenation
       would modify the array lower bound.
      </para>
     </listitem>

     <listitem>
      <para>
       Make command-line options of <application>postmaster</>
       and <link linkend="app-postgres"><application>postgres</></link>
       identical (Peter)
      </para>

      <para>
       This allows the postmaster to pass arguments to each backend
       without using <literal>-o</>.  Note that some options are now
       only available as long-form options, because there were conflicting
       single-letter options.
      </para>
     </listitem>

     <listitem>
      <para>
       Deprecate use of <application>postmaster</> symbolic link (Peter)
      </para>

      <para>
       <application>postmaster</> and <application>postgres</>
       commands now act identically, with the behavior determined
       by command-line options.  The <application>postmaster</> symbolic link is
       kept for compatibility, but is not really needed.
      </para>
     </listitem>

     <listitem>
      <para>
       Change <link
       linkend="guc-log-duration"><varname>log_duration</></link>
       to output even if the query is not output (Tom)
      </para>

      <para>
       In prior releases, <varname>log_duration</> only printed if
       the query appeared earlier in the log.
      </para>
     </listitem>

     <listitem>
      <para>
       Make <link
       linkend="functions-formatting"><function>to_char(time)</></link>
       and <link
       linkend="functions-formatting"><function>to_char(interval)</></link>
       treat <literal>HH</> and <literal>HH12</> as 12-hour
       intervals
      </para>

      <para>
       Most applications should use <literal>HH24</> unless they
       want a 12-hour display.
      </para>
     </listitem>

     <listitem>
      <para>
       Zero unmasked bits in conversion from <link
       linkend="datatype-inet"><type>INET</></link> to <link
       linkend="datatype-inet"><type>CIDR</></link> (Tom)
      </para>

      <para>
       This ensures that the converted value is actually valid for
       <type>CIDR</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <varname>australian_timezones</> configuration variable
       (Joachim Wieland)
      </para>

      <para>
       This variable has been superseded by a more general facility
       for configuring timezone abbreviations.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve cost estimation for nested-loop index scans (Tom)
      </para>

      <para>
       This might eliminate the need to set unrealistically small
       values of <link
       linkend="guc-random-page-cost"><varname>random_page_cost</></link>.
       If you have been using a very small <varname>random_page_cost</>,
       please recheck your test cases.
      </para>
     </listitem>

     <listitem>
      <para>
       Change behavior of <command>pg_dump</> <literal>-n</> and
       <literal>-t</> options.  (Greg Sabino Mullane)
      </para>
      <para>
       See the <command>pg_dump</> manual page for details.
      </para>
     </listitem>

     <listitem>
      <para>
       Change <link linkend="libpq"><application>libpq</></link>
       <function>PQdsplen()</> to return a useful value (Martijn
       van Oosterhout)
      </para>
     </listitem>

     <listitem>
      <para>
       Declare <link linkend="libpq"><application>libpq</></link>
       <function>PQgetssl()</> as returning <literal>void *</>,
       rather than <literal>SSL *</> (Martijn van Oosterhout)
      </para>

      <para>
       This allows applications to use the function without including
       the OpenSSL headers.
      </para>
     </listitem>

     <listitem>
      <para>
       C-language loadable modules must now include a
       <link linkend="xfunc-c-dynload"><literal>PG_MODULE_MAGIC</></link>
       macro call for version compatibility checking
       (Martijn van Oosterhout)
      </para>
     </listitem>

     <listitem>
      <para>
       For security's sake, modules used by a PL/PerlU function are no
       longer available to PL/Perl functions (Andrew)
      </para>
      <note>
       <para>
        This also implies that data can no longer be shared between a PL/Perl
        function and a PL/PerlU function.
        Some Perl installations have not been compiled with the correct flags
        to allow multiple interpreters to exist within a single process.
        In this situation PL/Perl and PL/PerlU cannot both be used in a
        single backend. The solution is to get a Perl installation which
        supports multiple interpreters.
       </para>
      </note>
     </listitem>

     <listitem>
      <para>
       In <filename>contrib/xml2/</>, rename <function>xml_valid()</> to
       <function>xml_is_well_formed()</> (Tom)
      </para>

      <para>
       <function>xml_valid()</> will remain for backward compatibility,
       but its behavior will change to do schema checking in a future
       release.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <filename>contrib/ora2pg/</>, now at <ulink
       url="http://www.samse.fr/GPL/ora2pg"></ulink>
      </para>
     </listitem>

     <listitem>
      <para>
       Remove contrib modules that have been migrated to PgFoundry:
       <filename>adddepend</>, <filename>dbase</>, <filename>dbmirror</>,
       <filename>fulltextindex</>, <filename>mac</>, <filename>userlock</>
      </para>
     </listitem>

     <listitem>
      <para>
       Remove abandoned contrib modules:
       <filename>mSQL-interface</>, <filename>tips</>
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <acronym>QNX</> and <acronym>BEOS</> ports (Bruce)
      </para>

      <para>
       These ports no longer had active maintainers.
      </para>
     </listitem>

   </itemizedlist>
  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    Below you will find a detailed account of the
    changes between <productname>PostgreSQL</productname> 8.2 and
    the previous major release.
   </para>

   <sect3>
    <title>Performance Improvements</title>
    <itemizedlist>

     <listitem>
      <para>
       Allow the planner to reorder <link linkend="queries-join">outer
       joins</link> in some circumstances (Tom)
      </para>

      <para>
       In previous releases, outer joins would always be evaluated in
       the order written in the query. This change allows the
       query optimizer to consider reordering outer joins, in cases where
       it can determine that the join order can be changed without
       altering the meaning of the query.  This can make a
       considerable performance difference for queries involving
       multiple outer joins or mixed inner and outer joins.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve efficiency of <link
       linkend="functions-comparisons"><literal>IN</>
       (list-of-expressions)</link> clauses (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve sorting speed and reduce memory usage (Simon, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve subtransaction performance (Alvaro, Itagaki Takahiro,
       Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>FILLFACTOR</> to <link
       linkend="SQL-CREATETABLE">table</link> and <link
       linkend="SQL-CREATEINDEX">index</link> creation (ITAGAKI
       Takahiro)
      </para>

      <para>
       This leaves extra free space in each table or index page,
       allowing improved performance as the database grows.  This
       is particularly valuable to maintain clustering.
      </para>
     </listitem>

     <listitem>
      <para>
       Increase default values for <link
       linkend="guc-shared-buffers"><varname>shared_buffers</></link>
       and <link
       linkend="guc-max-fsm-pages"><varname>max_fsm_pages</></link>
       (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve locking performance by breaking the lock manager tables into
       sections
       (Tom)
      </para>

      <para>
       This allows locking to be more fine-grained, reducing
       contention.
      </para>
     </listitem>

     <listitem>
      <para>
       Reduce locking requirements of sequential scans (Qingqing
       Zhou)
      </para>
     </listitem>

     <listitem>
      <para>
       Reduce locking required for database creation and destruction
       (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve the optimizer's selectivity estimates for <link
       linkend="functions-like"><literal>LIKE</></link>, <link
       linkend="functions-like"><literal>ILIKE</></link>, and
       <link linkend="functions-posix-regexp">regular expression</link>
       operations (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve planning of joins to <link linkend="ddl-inherit">inherited
       tables</link> and <link linkend="queries-union"><literal>UNION
       ALL</></link> views (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <link linkend="guc-constraint-exclusion">constraint
       exclusion</link> to be applied to <link
       linkend="ddl-inherit">inherited</link> <command>UPDATE</> and
       <command>DELETE</> queries (Tom)
      </para>

      <para>
       <command>SELECT</> already honored constraint exclusion.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve planning of constant <literal>WHERE</> clauses, such as
       a condition that depends only on variables inherited from an
       outer query level (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Protocol-level unnamed prepared statements are re-planned
       for each set of <literal>BIND</> values (Tom)
      </para>

      <para>
       This improves performance because the exact parameter values
       can be used in the plan.
      </para>
     </listitem>

     <listitem>
      <para>
       Speed up vacuuming of B-Tree indexes (Heikki Linnakangas,
       Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Avoid extra scan of tables without indexes during <link
       linkend="SQL-VACUUM"><command>VACUUM</></link> (Greg Stark)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve multicolumn <link linkend="GiST"><acronym>GiST</></link>
       indexing (Oleg, Teodor)
      </para>
     </listitem>

     <listitem>
      <para>
       Remove dead index entries before B-Tree page split (Junji
       Teramoto)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Server Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Allow a forced switch to a new transaction log file (Simon, Tom)
      </para>

      <para>
       This is valuable for keeping warm standby slave servers
       in sync with the master.  Transaction log file switching now also happens
       automatically during <link
       linkend="functions-admin"><function>pg_stop_backup()</></link>.
       This ensures that all
       transaction log files needed for recovery can be archived immediately.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <acronym>WAL</> informational functions (Simon)
      </para>

      <para>
       Add functions for interrogating the current transaction log insertion
       point and determining <acronym>WAL</> filenames from the
       hex <acronym>WAL</> locations displayed by <link
       linkend="functions-admin"><function>pg_stop_backup()</></link>
       and related functions.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve recovery from a crash during <acronym>WAL</> replay (Simon)
      </para>

      <para>
       The server now does periodic checkpoints during <acronym>WAL</>
       recovery, so if there is a crash, future <acronym>WAL</>
       recovery is shortened.  This also eliminates the need for
       warm standby servers to replay the entire log since the
       base backup if they crash.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve reliability of long-term <acronym>WAL</> replay
       (Heikki, Simon, Tom)
      </para>

      <para>
       Formerly, trying to roll forward through more than 2 billion
       transactions would not work due to XID wraparound.  This meant
       warm standby servers had to be reloaded
       from fresh base backups periodically.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link
       linkend="guc-archive-timeout"><varname>archive_timeout</></link>
       to force transaction log file switches at a given interval (Simon)
      </para>

      <para>
       This enforces a maximum replication delay for warm standby servers.
      </para>
     </listitem>

     <listitem>
      <para>
       Add native <link linkend="auth-ldap"><acronym>LDAP</></link>
       authentication (Magnus Hagander)
      </para>

      <para>
       This is particularly useful for platforms that do not
       support <acronym>PAM</>, such as Windows.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link linkend="sql-grant-description-objects"><literal>GRANT
       CONNECT ON DATABASE</></link> (Gevik Babakhani)
      </para>

      <para>
       This gives SQL-level control over database access.  It works as
       an additional filter on top of the existing
       <link linkend="auth-pg-hba-conf"><filename>pg_hba.conf</></link>
       controls.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for <link linkend="ssl-tcp"><acronym>SSL</>
       Certificate Revocation List</link> (<acronym>CRL</>) files
       (Libor Hoho&scaron;)
      </para>

      <para>
       The server and <application>libpq</> both recognize <acronym>CRL</>
       files now.
      </para>
     </listitem>

     <listitem>
      <para>
       <link linkend="GiST"><acronym>GiST</></link> indexes are
       now clusterable (Teodor)
      </para>
     </listitem>

     <listitem>
      <para>
       Remove routine autovacuum server log entries (Bruce)
      </para>

      <para>
       <link
       linkend="monitoring-stats-views-table"><literal>pg_stat_activity</></link>
       now shows autovacuum activity.
      </para>
     </listitem>

     <listitem>
      <para>
       Track maximum XID age within individual tables, instead of whole databases (Alvaro)
      </para>

      <para>
       This reduces the overhead involved in preventing transaction
       ID wraparound, by avoiding unnecessary VACUUMs.
      </para>
     </listitem>

     <listitem>
      <para>
       Add last vacuum and analyze timestamp columns to the stats
       collector (Larry Rosenman)
      </para>

      <para>
       These values now appear in the <link
       linkend="monitoring-stats-views-table"><literal>pg_stat_*_tables</></link>
       system views.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve performance of statistics monitoring, especially
       <varname>stats_command_string</>
       (Tom, Bruce)
      </para>

      <para>
       This release enables <varname>stats_command_string</> by
       default, now that its overhead is minimal.  This means
       <link
       linkend="monitoring-stats-views-table"><literal>pg_stat_activity</></link>
       will now show all active queries by default.
      </para>
     </listitem>

     <listitem>
      <para>
       Add a <literal>waiting</> column to <link
       linkend="monitoring-stats-views-table"><literal>pg_stat_activity</></link>
       (Tom)
      </para>

      <para>
       This allows <structname>pg_stat_activity</> to show all the
       information included in the <application>ps</> display.
      </para>
     </listitem>

     <listitem>
      <para>
       Add configuration parameter <link
       linkend="guc-update-process-title"><varname>update_process_title</></link>
       to control whether the <application>ps</> display is updated
       for every command (Bruce)
      </para>

      <para>
       On platforms where it is expensive to update the <application>ps</>
       display, it might be worthwhile to turn this off and rely solely on
       <structname>pg_stat_activity</> for status information.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow units to be specified in configuration settings
       (Peter)
      </para>

      <para>
       For example, you can now set <link
       linkend="guc-shared-buffers"><varname>shared_buffers</></link>
       to <literal>32MB</> rather than mentally converting sizes.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for <link linkend="config-setting">include
       directives</link> in <filename>postgresql.conf</> (Joachim
       Wieland)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve logging of protocol-level prepare/bind/execute
       messages (Bruce, Tom)
      </para>

      <para>
       Such logging now shows statement names, bind parameter
       values, and the text of the query being executed.  Also,
       the query text is properly included in logged error messages
       when enabled by <varname>log_min_error_statement</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Prevent <link
       linkend="guc-max-stack-depth"><varname>max_stack_depth</></link>
       from being set to unsafe values
      </para>

      <para>
       On platforms where we can determine the actual kernel stack depth
       limit (which is most), make sure that the initial default value of
       <varname>max_stack_depth</> is safe, and reject attempts to set it
       to unsafely large values.
      </para>
     </listitem>

     <listitem>
      <para>
       Enable highlighting of error location in query in more
       cases (Tom)
      </para>

      <para>
       The server is now able to report a specific error location for
       some semantic errors (such as unrecognized column name), rather
       than just for basic syntax errors as before.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <quote>failed to re-find parent key</> errors in
       <command>VACUUM</> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Clean out <filename>pg_internal.init</> cache files during server
       restart (Simon)
      </para>

      <para>
       This avoids a hazard that the cache files might contain stale
       data after PITR recovery.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix race condition for truncation of a large relation across a
       gigabyte boundary by <command>VACUUM</> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix bug causing needless deadlock errors on row-level locks (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix bugs affecting multi-gigabyte hash indexes (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Each backend process is now its own process group leader (Tom)
      </para>

      <para>
       This allows query cancel to abort subprocesses invoked from a
       backend or archive/recovery process.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Query Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add <link linkend="SQL-INSERT"><command>INSERT</></link>/<link
       linkend="SQL-UPDATE"><command>UPDATE</></link>/<link
       linkend="SQL-DELETE"><command>DELETE</></link>
       <literal>RETURNING</> (Jonah Harris, Tom)
      </para>

      <para>
       This allows these commands to return values, such as the
       computed serial key for a new row.  In the <command>UPDATE</>
       case, values from the updated version of the row are returned.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for multiple-row <link
       linkend="queries-values"><literal>VALUES</></link> clauses,
       per SQL standard (Joe, Tom)
      </para>

      <para>
       This allows <command>INSERT</> to insert multiple rows of
       constants, or queries to generate result sets using constants.
       For example, <literal>INSERT ...  VALUES (...), (...),
       ....</>, and <literal>SELECT * FROM (VALUES (...), (...),
       ....) AS alias(f1, ...)</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <link linkend="SQL-UPDATE"><command>UPDATE</></link>
       and <link linkend="SQL-DELETE"><command>DELETE</></link>
       to use an alias for the target table (Atsushi Ogawa)
      </para>

      <para>
       The SQL standard does not permit an alias in these commands, but
       many database systems allow one anyway for notational convenience.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <link linkend="SQL-UPDATE"><command>UPDATE</></link>
       to set multiple columns with a list of values (Susanne
       Ebrecht)
      </para>

      <para>
       This is basically a short-hand for assigning the columns
       and values in pairs.  The syntax is <literal>UPDATE tab
       SET (<replaceable>column</>, ...) = (<replaceable>val</>, ...)</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Make row comparisons work per standard (Tom)
      </para>

      <para>
       The forms &lt;, &lt;=, &gt;, &gt;= now compare rows lexicographically,
       that is, compare the first elements, if equal compare the second
       elements, and so on.  Formerly they expanded to an AND condition
       across all the elements, which was neither standard nor very useful.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link linkend="SQL-TRUNCATE"><literal>CASCADE</></link>
       option to <command>TRUNCATE</> (Joachim Wieland)
      </para>

      <para>
       This causes <command>TRUNCATE</> to automatically include all tables
       that reference the specified table(s) via foreign keys.  While
       convenient, this is a dangerous tool &mdash; use with caution!
      </para>
     </listitem>

     <listitem>
      <para>
       Support <literal>FOR UPDATE</> and <literal>FOR SHARE</>
       in the same <link linkend="SQL-INSERT"><literal>SELECT</></link>
       command (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link linkend="functions-comparisons"><literal>IS NOT
       DISTINCT FROM</></link> (Pavel Stehule)
      </para>

      <para>
       This operator is similar to equality (<literal>=</>), but
       evaluates to true when both left and right operands are
       <literal>NULL</>, and to false when just one is, rather than
       yielding <literal>NULL</> in these cases.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve the length output used by <link
       linkend="queries-union"><literal>UNION</></link>/<literal>INTERSECT</>/<literal>EXCEPT</>
       (Tom)
      </para>

      <para>
       When all corresponding columns are of the same defined length, that
       length is used for the result, rather than a generic length.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <link linkend="functions-like"><literal>ILIKE</></link>
       to work for multi-byte encodings (Tom)
      </para>

      <para>
       Internally, <literal>ILIKE</> now calls <function>lower()</>
       and then uses <literal>LIKE</>.  Locale-specific regular
       expression patterns still do not work in these encodings.
      </para>
     </listitem>

     <listitem>
      <para>
       Enable <link
       linkend="guc-standard-conforming-strings"><varname>standard_conforming_strings</></link>
       to be turned <literal>on</> (Kevin Grittner)
      </para>

      <para>
       This allows backslash escaping in strings to be disabled,
       making <productname>PostgreSQL</> more
       standards-compliant.  The default is <literal>off</> for backwards
       compatibility, but future releases will default this to <literal>on</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Do not flatten subqueries that contain <literal>volatile</>
       functions in their target lists (Jaime Casanova)
      </para>

      <para>
       This prevents surprising behavior due to multiple evaluation
       of a <literal>volatile</> function (such as <function>random()</>
       or <function>nextval()</>).  It might cause performance
       degradation in the presence of functions that are unnecessarily
       marked as <literal>volatile</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add system views <link
       linkend="view-pg-prepared-statements"><literal>pg_prepared_statements</></link>
       and <link
       linkend="view-pg-cursors"><literal>pg_cursors</></link>
       to show prepared statements and open cursors (Joachim Wieland, Neil)
      </para>

      <para>
       These are very useful in pooled connection setups.
      </para>
     </listitem>

     <listitem>
      <para>
       Support portal parameters in <link
       linkend="SQL-EXPLAIN"><command>EXPLAIN</></link> and <link
       linkend="SQL-EXECUTE"><command>EXECUTE</></link> (Tom)
      </para>

      <para>
       This allows, for example, <acronym>JDBC</> <literal>?</> parameters to
       work in these commands.
      </para>
     </listitem>

     <listitem>
      <para>
       If <acronym>SQL</>-level <link
       linkend="SQL-PREPARE"><command>PREPARE</></link> parameters
       are unspecified, infer their types from the content of the
       query (Neil)
      </para>

      <para>
       Protocol-level <command>PREPARE</> already did this.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <literal>LIMIT</> and <literal>OFFSET</> to exceed
       two billion (Dhanaraj M)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Object Manipulation Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add <literal>TABLESPACE</> clause to <link
       linkend="SQL-CREATETABLEAS"><command>CREATE TABLE AS</></link>
       (Neil)
      </para>

      <para>
       This allows a tablespace to be specified for the new table.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>ON COMMIT</> clause to <link
       linkend="SQL-CREATETABLEAS"><command>CREATE TABLE AS</></link>
       (Neil)
      </para>

      <para>
       This allows temporary tables to be truncated or dropped on
       transaction commit.  The default behavior is for the table
       to remain until the session ends.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>INCLUDING CONSTRAINTS</> to <link
       linkend="SQL-CREATETABLE"><command>CREATE TABLE LIKE</></link>
       (Greg Stark)
      </para>

      <para>
       This allows easy copying of <literal>CHECK</> constraints to a new
       table.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow the creation of placeholder (shell) <link
       linkend="SQL-CREATETYPE">types</link> (Martijn van Oosterhout)
      </para>

      <para>
       A shell type declaration creates a type name, without specifying
       any of the details of the type.  Making a shell type is useful
       because it allows cleaner declaration of the type's input/output
       functions, which must exist before the type can be defined <quote>for
       real</>.  The syntax is <command>CREATE TYPE <replaceable
       class="parameter">typename</replaceable></>.
      </para>
     </listitem>

     <listitem>
      <para>
       <link linkend="SQL-CREATEAGGREGATE">Aggregate functions</link>
       now support multiple input parameters (Sergey Koposov, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add new aggregate creation <link
       linkend="SQL-CREATEAGGREGATE">syntax</link> (Tom)
      </para>

      <para>
       The new syntax is <command>CREATE AGGREGATE
       <replaceable>aggname</> (<replaceable>input_type</>)
       (<replaceable>parameter_list</>)</command>.  This more
       naturally supports the new multi-parameter aggregate
       functionality.  The previous syntax is still supported.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link
       linkend="SQL-ALTERROLE"><command>ALTER ROLE PASSWORD NULL</></link>
       to remove a previously set role password (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <command>DROP</> object <literal>IF EXISTS</> for many
       object types (Andrew)
      </para>

      <para>
       This allows <command>DROP</> operations on non-existent
       objects without generating an error.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link linkend="SQL-DROP-OWNED"><literal>DROP OWNED</></link>
       to drop all objects owned by a role (Alvaro)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link linkend="SQL-REASSIGN-OWNED"><literal>REASSIGN
       OWNED</></link> to reassign ownership of all objects owned
       by a role (Alvaro)
      </para>

      <para>
       This, and <literal>DROP OWNED</> above, facilitate dropping
       roles.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link linkend="SQL-GRANT"><command>GRANT ON SEQUENCE</></link>
       syntax (Bruce)
      </para>

      <para>
       This was added for setting sequence-specific permissions.
       <literal>GRANT ON TABLE</> for sequences is still supported
       for backward compatibility.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link linkend="SQL-GRANT"><literal>USAGE</></link>
       permission for sequences that allows only <function>currval()</>
       and <function>nextval()</>, not <function>setval()</>
       (Bruce)
      </para>

      <para>
       <literal>USAGE</> permission allows more fine-grained
       control over sequence access.  Granting <literal>USAGE</>
       allows users to increment
       a sequence, but prevents them from setting the sequence to
       an arbitrary value using <function>setval()</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link linkend="SQL-ALTERTABLE"><literal>ALTER TABLE
       [ NO ] INHERIT</></link> (Greg Stark)
      </para>

      <para>
       This allows inheritance to be adjusted dynamically, rather than
       just at table creation and destruction.  This is very valuable
       when using inheritance to implement table partitioning.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <link linkend="SQL-COMMENT">comments</link> on global
       objects to be stored globally (Kris Jurka)
      </para>

      <para>
       Previously, comments attached to databases were stored in individual
       databases, making them ineffective, and there was no provision
       at all for comments on roles or tablespaces.  This change adds a new
       shared catalog <link
       linkend="catalog-pg-shdescription"><structname>pg_shdescription</structname></link>
       and stores comments on databases, roles, and tablespaces therein.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Utility Command Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add option to allow indexes to be created without blocking
       concurrent writes to the table (Greg Stark, Tom)
      </para>

      <para>
       The new syntax is <link linkend="SQL-CREATEINDEX"><command>CREATE
       INDEX CONCURRENTLY</></link>.  The default behavior is
       still to block table modification while a index is being
       created.
      </para>
     </listitem>

     <listitem>
      <para>
       Provide <link linkend="functions-advisory-locks">advisory
       locking</link> functionality (Abhijit Menon-Sen, Tom)
      </para>

      <para>
       This is a new locking API designed to replace what used to be
       in /contrib/userlock.  The userlock code is now on pgfoundry.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <link linkend="SQL-COPY"><command>COPY</></link> to
       dump a <command>SELECT</> query (Zoltan Boszormenyi, Karel
       Zak)
      </para>

      <para>
       This allows <command>COPY</> to dump arbitrary <acronym>SQL</>
       queries. The syntax is <literal>COPY (SELECT ...) TO</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Make the <link linkend="SQL-COPY"><command>COPY</></link>
       command return a command tag that includes the number of
       rows copied (Volkan YAZICI)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <link linkend="SQL-VACUUM"><command>VACUUM</></link>
       to expire rows without being affected by other concurrent
       <command>VACUUM</> operations (Hannu Krossing, Alvaro, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <link linkend="APP-INITDB"><application>initdb</></link>
       detect the operating system locale and set the default
       <varname>DateStyle</> accordingly (Peter)
      </para>

      <para>
       This makes it more likely that the installed
       <filename>postgresql.conf</> <varname>DateStyle</> value will
       be as desired.
      </para>
     </listitem>

     <listitem>
      <para>
       Reduce number of progress messages displayed by <application>initdb</> (Tom)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Date/Time Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Allow full timezone names in <link
       linkend="datatype-datetime"><type>timestamp</></link> input values
       (Joachim Wieland)
      </para>

      <para>
       For example, <literal>'2006-05-24 21:11
       America/New_York'::timestamptz</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Support configurable timezone abbreviations (Joachim Wieland)
      </para>

      <para>
       A desired set of timezone abbreviations can be chosen via the
       configuration parameter <link
       linkend="guc-timezone-abbreviations"><varname>timezone_abbreviations</></link>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link
       linkend="view-pg-timezone-abbrevs"><varname>pg_timezone_abbrevs</></link>
       and <link
       linkend="view-pg-timezone-names"><varname>pg_timezone_names</></link>
       views to show supported timezones (Magnus Hagander)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link
       linkend="functions-datetime-table"><function>clock_timestamp()</></link>,
       <link
       linkend="functions-datetime-table"><function>statement_timestamp()</></link>,
       and <link
       linkend="functions-datetime-table"><function>transaction_timestamp()</></link>
       (Bruce)
      </para>

      <para>
       <function>clock_timestamp()</> is the current wall-clock time,
       <function>statement_timestamp()</> is the time the current
       statement arrived at the server, and
       <function>transaction_timestamp()</> is an alias for
       <function>now()</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <link
       linkend="functions-formatting"><function>to_char()</></link>
       to print localized month and day names (Euler Taveira de
       Oliveira)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <link
       linkend="functions-formatting"><function>to_char(time)</></link>
       and <link
       linkend="functions-formatting"><function>to_char(interval)</></link>
       to output <acronym>AM</>/<acronym>PM</> specifications
       (Bruce)
      </para>

      <para>
       Intervals and times are treated as 24-hour periods, e.g.
       <literal>25 hours</> is considered <acronym>AM</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add new function <link
       linkend="functions-datetime-table"><function>justify_interval()</></link>
       to adjust interval units (Mark Dilger)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow timezone offsets up to 14:59 away from GMT
      </para>

      <para>
       Kiribati uses GMT+14, so we'd better accept that.
      </para>
     </listitem>

     <listitem>
      <para>
       Interval computation improvements (Michael Glaesemann, Bruce)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Other Data Type and Function Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Allow arrays to contain <literal>NULL</> elements (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow assignment to array elements not contiguous with the existing
       entries (Tom)
      </para>

      <para>
       The intervening array positions will be filled with nulls.
       This is per SQL standard.
      </para>
     </listitem>

     <listitem>
      <para>
       New built-in <link linkend="functions-array">operators</link>
       for array-subset comparisons (<literal>@&gt;</>,
       <literal>&lt;@</>, <literal>&amp;&amp;</>) (Teodor, Tom)
      </para>

      <para>
       These operators can be indexed for many data types using
       <acronym>GiST</> or <acronym>GIN</> indexes.
      </para>
     </listitem>

     <listitem>
      <para>
       Add convenient arithmetic <link
       linkend="cidr-inet-operators-table">operations</link> on
       <type>INET</>/<type>CIDR</> values (Stephen R. van den
       Berg)
      </para>

      <para>
       The new operators are <literal>&amp;</> (and), <literal>|</>
       (or), <literal>~</> (not), <type>inet</> <literal>+</> <type>int8</>,
       <type>inet</> <literal>-</> <type>int8</>, and
       <type>inet</> <literal>-</> <type>inet</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add new <link
       linkend="functions-aggregate-statistics-table">aggregate functions</link>
       from SQL:2003 (Neil)
      </para>

      <para>
       The new functions are <function>var_pop()</>,
       <function>var_samp()</>, <function>stddev_pop()</>, and
       <function>stddev_samp()</>.  <function>var_samp()</> and
       <function>stddev_samp()</> are merely renamings of the
       existing aggregates <function>variance()</> and
       <function>stddev()</>.  The latter names remain available
       for backward compatibility.
      </para>
     </listitem>

     <listitem>
      <para>
       Add SQL:2003 statistical <link
       linkend="functions-aggregate-statistics-table">aggregates</link>
       (Sergey Koposov)
      </para>

      <para>
       New functions:  <function>regr_intercept()</>,
       <function>regr_slope()</>, <function>regr_r2()</>,
       <function>corr()</>, <function>covar_samp()</>,
       <function>covar_pop()</>, <function>regr_avgx()</>,
       <function>regr_avgy()</>, <function>regr_sxy()</>,
       <function>regr_sxx()</>, <function>regr_syy()</>,
       <function>regr_count()</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <link linkend="SQL-CREATEDOMAIN">domains</link> to be
       based on other domains (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Properly enforce domain <link
       linkend="ddl-constraints"><literal>CHECK</></link> constraints
       everywhere (Neil, Tom)
      </para>

      <para>
       For example, the result of a user-defined function that is
       declared to return a domain type is now checked against the
       domain's constraints. This closes a significant hole in the domain
       implementation.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix problems with dumping renamed <link
       linkend="datatype-serial"><type>SERIAL</></link> columns
       (Tom)
      </para>

      <para>
       The fix is to dump a <type>SERIAL</> column by explicitly
       specifying its <literal>DEFAULT</> and sequence elements,
       and reconstructing the <type>SERIAL</> column on reload
       using a new <link linkend="SQL-ALTERSEQUENCE"><command>ALTER
       SEQUENCE OWNED BY</></link> command.  This also allows
       dropping a <type>SERIAL</> column specification.
      </para>
     </listitem>

     <listitem>
      <para>
       Add a server-side sleep function <link
       linkend="functions-datetime-delay"><function>pg_sleep()</></link>
       (Joachim Wieland)
      </para>
     </listitem>

     <listitem>
      <para>
       Add all comparison operators for the <link
       linkend="datatype-oid"><type>tid</></link> (tuple id) data
       type (Mark Kirkwood, Greg Stark, Tom)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>PL/PgSQL Server-Side Language Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add <literal>TG_table_name</> and <literal>TG_table_schema</> to
       trigger parameters (Andrew)
      </para>

      <para>
       <literal>TG_relname</> is now deprecated.  Comparable
       changes have been made in the trigger parameters for the other
       PLs as well.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <literal>FOR</> statements to return values to scalars
       as well as records and row types (Pavel Stehule)
      </para>
     </listitem>

     <listitem>
      <para>
       Add a <literal>BY</> clause to the <literal>FOR</> loop,
       to control the iteration increment (Jaime Casanova)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>STRICT</> to <link
       linkend="plpgsql-statements-sql-onerow"><command>SELECT
       INTO</></link> (Matt Miller)
      </para>

      <para>
       <literal>STRICT</> mode throws an exception if more or less
       than one row is returned by the <command>SELECT</>, for
       <productname>Oracle PL/SQL</> compatibility.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>PL/Perl Server-Side Language Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add <literal>table_name</> and <literal>table_schema</> to
       trigger parameters (Adam Sj&oslash;gren)
      </para>
     </listitem>

     <listitem>
      <para>
       Add prepared queries (Dmitry Karasik)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <literal>$_TD</> trigger data a global variable (Andrew)
      </para>

      <para>
       Previously, it was lexical, which caused unexpected sharing
       violations.
      </para>
     </listitem>

     <listitem>
      <para>
       Run PL/Perl and PL/PerlU in separate interpreters, for security
       reasons (Andrew)
      </para>
      <para>
       In consequence, they can no longer share data nor loaded modules.
       Also, if Perl has not been compiled with the requisite flags to
       allow multiple interpreters, only one of these languages can be used
       in any given backend process.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>PL/Python Server-Side Language Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Named parameters are passed as ordinary variables, as well as in the
       <literal>args[]</> array (Sven Suursoho)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>table_name</> and <literal>table_schema</> to
       trigger parameters (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow returning of composite types and result sets (Sven Suursoho)
      </para>
     </listitem>

     <listitem>
      <para>
       Return result-set as <literal>list</>, <literal>iterator</>,
       or <literal>generator </>(Sven Suursoho)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow functions to return <literal>void</> (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Python 2.5 is now supported (Tom)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title><link linkend="APP-PSQL"><application>psql</></link> Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add new command <literal>\password</> for changing role
       password with client-side password encryption (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <literal>\c</> to connect to a new host and port
       number (David, Volkan YAZICI)
      </para>
     </listitem>

     <listitem>
      <para>
       Add tablespace display to <literal>\l+</> (Philip Yarra)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve <literal>\df</> slash command to include the argument
       names and modes (<literal>OUT</> or <literal>INOUT</>) of
       the function (David Fetter)
      </para>
     </listitem>

     <listitem>
      <para>
       Support binary <command>COPY</> (Andreas Pflug)
      </para>
     </listitem>

     <listitem>
      <para>
       Add option to run the entire session in a single transaction
       (Simon)
      </para>

      <para>
       Use option <literal>-1</> or <literal>--single-transaction</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Support for automatically retrieving <command>SELECT</>
       results in batches using a cursor (Chris Mair)
      </para>

      <para>
       This is enabled using <command>\set FETCH_COUNT
       <replaceable>n</></command>. This
       feature allows large result sets to be retrieved in
       <application>psql</> without attempting to buffer the entire
       result set in memory.
      </para>
     </listitem>

     <listitem>
      <para>
       Make multi-line values align in the proper column
       (Martijn van Oosterhout)
      </para>

      <para>
       Field values containing newlines are now displayed in a more
       readable fashion.
      </para>
     </listitem>

     <listitem>
      <para>
       Save multi-line statements as a single entry, rather than
       one line at a time (Sergey E. Koposov)
      </para>

      <para>
       This makes up-arrow recall of queries easier.  (This is
       not available on Windows, because that platform uses the native
       command-line editing present in the operating system.)
      </para>
     </listitem>

     <listitem>
      <para>
       Make the line counter 64-bit so it can handle files with more
       than two billion lines (David Fetter)
      </para>
     </listitem>

     <listitem>
      <para>
       Report both the returned data and the command status tag
       for <command>INSERT</>/<command>UPDATE</>/<command>DELETE
       RETURNING</> (Tom)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title><link linkend="APP-PGDUMP"><application>pg_dump</></link> Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Allow complex selection of objects to be included or excluded
       by <application>pg_dump</> (Greg Sabino Mullane)
      </para>

      <para>
       <application>pg_dump</> now supports multiple <literal>-n</>
       (schema) and <literal>-t</> (table) options, and adds
       <literal>-N</> and <literal>-T</> options to exclude objects.
       Also, the arguments of these switches can now be wild-card expressions
       rather than single object names, for example
       <literal>-t 'foo*'</>, and a schema can be part of
       a <literal>-t</> or <literal>-T</> switch, for example
       <literal>-t schema1.table1</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link linkend="APP-PGRESTORE"><application>pg_restore</></link>
       <literal>--no-data-for-failed-tables</> option to suppress
       loading data if table creation failed (i.e., the table already
       exists) (Martin Pitt)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link linkend="APP-PGRESTORE"><application>pg_restore</></link>
       option to run the entire session in a single transaction
       (Simon)
      </para>

      <para>
       Use option <literal>-1</> or <literal>--single-transaction</>.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title><link linkend="libpq"><application>libpq</></link> Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add <link
       linkend="libpq-misc"><function>PQencryptPassword()</></link>
       to encrypt passwords (Tom)
      </para>

      <para>
       This allows passwords to be sent pre-encrypted for commands
       like <link linkend="SQL-ALTERROLE"><command>ALTER ROLE ...
       PASSWORD</></link>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add function <link
       linkend="libpq-threading"><function>PQisthreadsafe()</></link>
       (Bruce)
      </para>

      <para>
       This allows applications to query the thread-safety status
       of the library.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link
       linkend="libpq-exec-main"><function>PQdescribePrepared()</></link>,
       <link
       linkend="libpq-exec-main"><function>PQdescribePortal()</></link>,
       and related functions to return information about previously
       prepared statements and open cursors (Volkan YAZICI)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <link linkend="libpq-ldap"><acronym>LDAP</></link> lookups
       from <link
       linkend="libpq-pgservice"><filename>pg_service.conf</></link>
       (Laurenz Albe)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow a hostname in <link
       linkend="libpq-pgpass"><filename>~/.pgpass</></link>
       to match the default socket directory (Bruce)
      </para>

      <para>
       A blank hostname continues to match any Unix-socket connection,
       but this addition allows entries that are specific to one of
       several postmasters on the machine.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title><link linkend="ecpg"><application>ecpg</></link> Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Allow <link linkend="SQL-SHOW"><command>SHOW</></link> to
       put its result into a variable (Joachim Wieland)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link linkend="SQL-COPY"><command>COPY TO STDOUT</></link>
       (Joachim Wieland)
      </para>
     </listitem>

     <listitem>
      <para>
       Add regression tests (Joachim Wieland, Michael)
      </para>
     </listitem>

     <listitem>
      <para>
       Major source code cleanups (Joachim Wieland, Michael)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title><application>Windows</> Port</title>
    <itemizedlist>

     <listitem>
      <para>
       Allow <acronym>MSVC</> to compile the <productname>PostgreSQL</>
       server (Magnus, Hiroshi Saito)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <acronym>MSVC</> support for utility commands and <link
       linkend="APP-PGDUMP"><application>pg_dump</></link> (Hiroshi
       Saito)
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for Windows code pages <literal>1253</>,
       <literal>1254</>, <literal>1255</>, and <literal>1257</>
       (Kris Jurka)
      </para>
     </listitem>

     <listitem>
      <para>
       Drop privileges on startup, so that the server can be started from
       an administrative account (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Stability fixes (Qingqing Zhou, Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Add native semaphore implementation (Qingqing Zhou)
      </para>

      <para>
       The previous code mimicked SysV semaphores.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Source Code Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add <link linkend="GIN"><acronym>GIN</></link> (Generalized
       Inverted iNdex) index access method (Teodor, Oleg)
      </para>
     </listitem>

     <listitem>
      <para>
       Remove R-tree indexing (Tom)
      </para>

      <para>
       Rtree has been re-implemented using <link
       linkend="GiST"><acronym>GiST</></link>. Among other
       differences, this means that rtree indexes now have support
       for crash recovery via write-ahead logging (WAL).
      </para>
     </listitem>

     <listitem>
      <para>
       Reduce libraries needlessly linked into the backend (Martijn
       van Oosterhout, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add a configure flag to allow libedit to be preferred over
       <acronym>GNU</> readline (Bruce)
      </para>

      <para>
       Use configure <link
       linkend="configure"><literal>--with-libedit-preferred</></link>.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow installation into directories containing spaces
       (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve ability to relocate installation directories (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for <productname>Solaris x86_64</> using the
       <productname>Solaris</> compiler (Pierre Girard, Theo
       Schlossnagle, Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <application>DTrace</> support (Robert Lor)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>PG_VERSION_NUM</> for use by third-party
       applications wanting to test the backend version in C using &gt;
       and &lt; comparisons (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>XLOG_BLCKSZ</> as independent from <literal>BLCKSZ</>
       (Mark Wong)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <literal>LWLOCK_STATS</> define to report locking
       activity (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Emit warnings for unknown <application>configure</> options
       (Martijn van Oosterhout)
      </para>
     </listitem>

     <listitem>
      <para>
       Add server support for <quote>plugin</> libraries
       that can be used for add-on tasks such as debugging and performance
       measurement (Korry Douglas)
      </para>

      <para>
       This consists of two features: a table of <quote>rendezvous
       variables</> that allows separately-loaded shared libraries to
       communicate, and a new configuration parameter <link
       linkend="guc-local-preload-libraries"><varname>local_preload_libraries</></link>
       that allows libraries to be loaded into specific sessions without
       explicit cooperation from the client application.  This allows
       external add-ons to implement features such as a PL/PgSQL debugger.
      </para>
     </listitem>

     <listitem>
      <para>
       Rename existing configuration parameter
       <varname>preload_libraries</> to <link
       linkend="guc-shared-preload-libraries"><varname>shared_preload_libraries</></link>
       (Tom)
      </para>

      <para>
       This was done for clarity in comparison to
       <varname>local_preload_libraries</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add new configuration parameter <link
       linkend="guc-server-version-num"><varname>server_version_num</></link>
       (Greg Sabino Mullane)
      </para>

      <para>
       This is like <varname>server_version</varname>, but is an
       integer, e.g.  <literal>80200</>. This allows applications to
       make version checks more easily.
      </para>
     </listitem>

     <listitem>
      <para>
       Add a configuration parameter <link
       linkend="guc-seq-page-cost"><varname>seq_page_cost</></link>
       (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Re-implement the <link linkend="regress">regression test</link> script as a C program
       (Magnus, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow loadable modules to allocate shared memory and
       lightweight locks (Marc Munro)
      </para>
     </listitem>

     <listitem>
      <para>
       Add automatic initialization and finalization of dynamically
       loaded libraries (Ralf Engelschall, Tom)
      </para>

      <para>
       New <link linkend="xfunc-c-dynload">functions</link>
       <function>_PG_init()</> and <function>_PG_fini()</> are
       called if the library defines such symbols.  Hence we no
       longer need to specify an initialization function in
       <varname>shared_preload_libraries</>; we can assume that
       the library used the <function>_PG_init()</> convention
       instead.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <link
       linkend="xfunc-c-dynload"><literal>PG_MODULE_MAGIC</></link>
       header block to all shared object files (Martijn van
       Oosterhout)
      </para>

      <para>
       The magic block prevents version mismatches between loadable object
       files and servers.
      </para>
     </listitem>

     <listitem>
      <para>
        Add shared library support for AIX (Laurenz Albe)
      </para>
     </listitem>

     <listitem>
      <para>
       New <link linkend="datatype-xml"><acronym>XML</></link>
       documentation section (Bruce)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Contrib Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Major tsearch2 improvements (Oleg, Teodor)
      </para>

      <itemizedlist>

       <listitem>
        <para>
         multibyte encoding support, including <acronym>UTF8</>
        </para>
       </listitem>
       <listitem>
        <para>
         query rewriting support
        </para>
       </listitem>
       <listitem>
        <para>
         improved ranking functions
        </para>
       </listitem>
       <listitem>
        <para>
         thesaurus dictionary support
        </para>
       </listitem>
       <listitem>
        <para>
         Ispell dictionaries now recognize <application>MySpell</>
         format, used by <application>OpenOffice</>
        </para>
       </listitem>
       <listitem>
        <para>
         <acronym>GIN</> support
        </para>
       </listitem>

      </itemizedlist>

     </listitem>

     <listitem>
      <para>
       Add adminpack module containing <application>Pgadmin</> administration
       functions (Dave)
      </para>

      <para>
       These functions provide additional file system access
       routines not present in the default <productname>PostgreSQL</>
       server.
      </para>
     </listitem>

     <listitem>
      <para>
       Add sslinfo module (Victor Wagner)
      </para>

      <para>
       Reports information about the current connection's <acronym>SSL</>
       certificate.
      </para>
     </listitem>

     <listitem>
      <para>
       Add pgrowlocks module (Tatsuo)
      </para>

      <para>
       This shows row locking information for a specified table.
      </para>
     </listitem>

     <listitem>
      <para>
       Add hstore module (Oleg, Teodor)
      </para>
     </listitem>

     <listitem>
      <para>
       Add isn module, replacing isbn_issn (Jeremy Kronuz)
      </para>

      <para>
       This new implementation supports <acronym>EAN13</>, <acronym>UPC</>,
       <acronym>ISBN</> (books), <acronym>ISMN</> (music), and
       <acronym>ISSN</> (serials).
      </para>
     </listitem>

     <listitem>
      <para>
       Add index information functions to pgstattuple (ITAGAKI Takahiro,
       Satoshi Nagayasu)
      </para>
     </listitem>

     <listitem>
      <para>
       Add pg_freespacemap module to display free space map information
       (Mark Kirkwood)
      </para>
     </listitem>

     <listitem>
      <para>
       pgcrypto now has all planned functionality (Marko Kreen)
      </para>
      <itemizedlist>
       <listitem>
        <para>
         Include iMath library in pgcrypto to have the public-key encryption
         functions always available.
        </para>
       </listitem>
       <listitem>
        <para>
         Add SHA224 algorithm that was missing in OpenBSD code.
        </para>
       </listitem>
       <listitem>
        <para>
         Activate builtin code for SHA224/256/384/512 hashes on older
         OpenSSL to have those algorithms always available.
        </para>
       </listitem>
       <listitem>
        <para>
         New function gen_random_bytes() that returns cryptographically strong
         randomness.  Useful for generating encryption keys.
        </para>
       </listitem>
       <listitem>
        <para>
         Remove digest_exists(), hmac_exists() and cipher_exists() functions.
        </para>
       </listitem>
      </itemizedlist>
     </listitem>

     <listitem>
      <para>
       Improvements to cube module (Joshua Reich)
      </para>

      <para>
       New functions are <function>cube(float[])</>,
       <function>cube(float[], float[])</>, and
       <function>cube_subset(cube, int4[])</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add async query capability to dblink (Kai Londenberg,
       Joe Conway)
      </para>
     </listitem>

     <listitem>
      <para>
       New operators for array-subset comparisons (<literal>@&gt;</>,
       <literal>&lt;@</>, <literal>&amp;&amp;</>) (Tom)
      </para>

      <para>
       Various contrib packages already had these operators for their
       datatypes, but the naming wasn't consistent.  We have now added
       consistently named array-subset comparison operators to the core code
       and all the contrib packages that have such functionality.
       (The old names remain available, but are deprecated.)
      </para>
     </listitem>

     <listitem>
      <para>
       Add uninstall scripts for all contrib packages that have install
       scripts (David, Josh Drake)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

  </sect2>
 </sect1>

 <sect1 id="release-8-1-10">
  <title>Release 8.1.10</title>

  <note>
  <title>Release date</title>
  <simpara>2007-09-17</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.1.9.
  </para>

  <sect2>
   <title>Migration to Version 8.1.10</title>

   <para>
    A dump/restore is not required for those running 8.1.X.
    However, if you are upgrading from a version earlier than 8.1.2,
    see the release notes for 8.1.2.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Prevent index corruption when a transaction inserts rows and
      then aborts close to the end of a concurrent <command>VACUUM</>
      on the same table (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Make <command>CREATE DOMAIN ... DEFAULT NULL</> work properly (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Allow the <type>interval</> data type to accept input consisting only of
      milliseconds or microseconds (Neil)
     </para>
    </listitem>

    <listitem>
     <para>
      Speed up rtree index insertion (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix excessive logging of <acronym>SSL</> error messages (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix logging so that log messages are never interleaved when using
      the syslogger process (Andrew)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix crash when <varname>log_min_error_statement</> logging runs out
      of memory (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix incorrect handling of some foreign-key corner cases (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Prevent <command>REINDEX</> and <command>CLUSTER</> from failing
      due to attempting to process temporary tables of other sessions (Alvaro)
     </para>
    </listitem>

    <listitem>
     <para>
      Update the time zone database rules, particularly New Zealand's upcoming changes (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Windows socket improvements (Magnus)
     </para>
    </listitem>

    <listitem>
     <para>
      Suppress timezone name (<literal>%Z</>) in log timestamps on Windows
      because of possible encoding mismatches (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Require non-superusers who use <filename>/contrib/dblink</> to use only
      password authentication, as a security measure (Joe)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-1-9">
  <title>Release 8.1.9</title>

  <note>
  <title>Release date</title>
  <simpara>2007-04-23</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.1.8,
   including a security fix.
  </para>

  <sect2>
   <title>Migration to Version 8.1.9</title>

   <para>
    A dump/restore is not required for those running 8.1.X.
    However, if you are upgrading from a version earlier than 8.1.2,
    see the release notes for 8.1.2.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
    <para>
     Support explicit placement of the temporary-table schema within
     <varname>search_path</>, and disable searching it for functions
     and operators (Tom)
    </para>
    <para>
     This is needed to allow a security-definer function to set a
     truly secure value of <varname>search_path</>.  Without it,
     an unprivileged SQL user can use temporary objects to execute code
     with the privileges of the security-definer function (CVE-2007-2138).
     See <command>CREATE FUNCTION</> for more information.
    </para>
    </listitem>

    <listitem>
    <para>
     <filename>/contrib/tsearch2</> crash fixes (Teodor)
    </para>
    </listitem>

    <listitem>
    <para>
     Require <command>COMMIT PREPARED</> to be executed in the same
     database as the transaction was prepared in (Heikki)
    </para>
    </listitem>

    <listitem>
    <para>
     Fix potential-data-corruption bug in how <command>VACUUM FULL</> handles
     <command>UPDATE</> chains (Tom, Pavan Deolasee)
    </para>
    </listitem>

    <listitem>
    <para>
     Planner fixes, including improving outer join and bitmap scan
     selection logic (Tom)
    </para>
    </listitem>

    <listitem>
    <para>
     Fix PANIC during enlargement of a hash index (bug introduced in 8.1.6)
     (Tom)
    </para>
    </listitem>

    <listitem>
    <para>
     Fix POSIX-style timezone specs to follow new USA DST rules (Tom)
    </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-1-8">
  <title>Release 8.1.8</title>

  <note>
  <title>Release date</title>
  <simpara>2007-02-07</simpara>
  </note>

  <para>
   This release contains one fix from 8.1.7.
  </para>

  <sect2>
   <title>Migration to Version 8.1.8</title>

   <para>
    A dump/restore is not required for those running 8.1.X.
    However, if you are upgrading from a version earlier than 8.1.2,
    see the release notes for 8.1.2.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
    <para>
     Remove overly-restrictive check for type length in constraints and
     functional indexes(Tom)
    </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-1-7">
  <title>Release 8.1.7</title>

  <note>
  <title>Release date</title>
  <simpara>2007-02-05</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.1.6, including
   a security fix.
  </para>

  <sect2>
   <title>Migration to Version 8.1.7</title>

   <para>
    A dump/restore is not required for those running 8.1.X.
    However, if you are upgrading from a version earlier than 8.1.2,
    see the release notes for 8.1.2.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
    <para>
     Remove security vulnerabilities that allowed connected users
     to read backend memory (Tom)
    </para>
    <para>
     The vulnerabilities involve suppressing the normal check that a SQL
     function returns the data type it's declared to, and changing the
     data type of a table column (CVE-2007-0555, CVE-2007-0556).  These
     errors can easily be exploited to cause a backend crash, and in
     principle might be used to read database content that the user
     should not be able to access.
    </para>
    </listitem>

    <listitem>
    <para>
     Fix rare bug wherein btree index page splits could fail
     due to choosing an infeasible split point (Heikki Linnakangas)
    </para>
    </listitem>

    <listitem>
    <para>
     Improve <command>VACUUM</> performance for databases with many tables (Tom)
    </para>
    </listitem>

    <listitem>
    <para>
     Fix autovacuum to avoid leaving non-permanent transaction IDs in
     non-connectable databases (Alvaro)
    </para>

    <para>
     This bug affects the 8.1 branch only.
    </para>
    </listitem>

    <listitem>
    <para>
     Fix for rare Assert() crash triggered by <literal>UNION</> (Tom)
    </para>
    </listitem>

    <listitem>
    <para>
     Tighten security of multi-byte character processing for UTF8 sequences
     over three bytes long (Tom)
    </para>
    </listitem>

    <listitem>
    <para>
     Fix bogus <quote>permission denied</> failures occurring on Windows
     due to attempts to fsync already-deleted files (Magnus, Tom)
    </para>
    </listitem>

    <listitem>
    <para>
     Fix possible crashes when an already-in-use PL/pgSQL function is
     updated (Tom)
    </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-1-6">
  <title>Release 8.1.6</title>

  <note>
  <title>Release date</title>
  <simpara>2007-01-08</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.1.5.
  </para>

  <sect2>
   <title>Migration to Version 8.1.6</title>

   <para>
    A dump/restore is not required for those running 8.1.X.
    However, if you are upgrading from a version earlier than 8.1.2,
    see the release notes for 8.1.2.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Improve handling of <function>getaddrinfo()</> on AIX (Tom)
     </para>

     <para>
      This fixes a problem with starting the statistics collector,
      among other things.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <application>pg_restore</> to handle a tar-format backup
      that contains large objects (blobs) with comments (Tom)
     </para>
    </listitem>

     <listitem>
      <para>
       Fix <quote>failed to re-find parent key</> errors in
       <command>VACUUM</> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Clean out <filename>pg_internal.init</> cache files during server
       restart (Simon)
      </para>

      <para>
       This avoids a hazard that the cache files might contain stale
       data after PITR recovery.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix race condition for truncation of a large relation across a
       gigabyte boundary by <command>VACUUM</> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix bug causing needless deadlock errors on row-level locks (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix bugs affecting multi-gigabyte hash indexes (Tom)
      </para>
     </listitem>

    <listitem>
     <para>
      Fix possible deadlock in Windows signal handling (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix error when constructing an <literal>ARRAY[]</> made up of multiple
      empty elements (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix ecpg memory leak during connection (Michael)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix for Darwin (OS X) compilation (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      <function>to_number()</> and <function>to_char(numeric)</>
      are now <literal>STABLE</>, not <literal>IMMUTABLE</>, for
      new <application>initdb</> installs (Tom)
     </para>

     <para>
      This is because <varname>lc_numeric</> can potentially
      change the output of these functions.
     </para>
    </listitem>

    <listitem>
     <para>
      Improve index usage of regular expressions that use parentheses (Tom)
     </para>

     <para>
      This improves <application>psql</> <literal>\d</> performance also.
     </para>
    </listitem>

    <listitem>
     <para>
      Update timezone database
     </para>

     <para>
      This affects Australian and Canadian daylight-savings rules in
      particular.
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-1-5">
  <title>Release 8.1.5</title>

  <note>
  <title>Release date</title>
  <simpara>2006-10-16</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.1.4.
  </para>

  <sect2>
   <title>Migration to Version 8.1.5</title>

   <para>
    A dump/restore is not required for those running 8.1.X.
    However, if you are upgrading from a version earlier than 8.1.2,
    see the release notes for 8.1.2.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Disallow aggregate functions in <command>UPDATE</>
commands, except within sub-SELECTs (Tom)</para>
<para>The behavior of such an aggregate was unpredictable, and in 8.1.X
could cause a crash, so it has been disabled.  The SQL standard does not allow
this either.</para></listitem>
<listitem><para>Fix core dump when an untyped literal is taken as
ANYARRAY</para></listitem>
<listitem><para>Fix core dump in duration logging for extended query protocol
when a <command>COMMIT</> or <command>ROLLBACK</> is
executed</para></listitem>
<listitem><para>Fix mishandling of AFTER triggers when query contains a SQL
function returning multiple rows (Tom)</para></listitem>
<listitem><para>Fix <command>ALTER TABLE ... TYPE</> to recheck
<literal>NOT NULL</> for <literal>USING</> clause (Tom)</para></listitem>
<listitem><para>Fix <function>string_to_array()</> to handle overlapping
 matches for the separator string</para>
<para>For example, <literal>string_to_array('123xx456xxx789', 'xx')</>.
</para></listitem>
<listitem><para>Fix <function>to_timestamp()</> for
<literal>AM</>/<literal>PM</> formats (Bruce)</para></listitem>
<listitem><para>Fix autovacuum's calculation that decides whether
 <command>ANALYZE</> is needed (Alvaro)</para></listitem>
<listitem><para>Fix corner cases in pattern matching for
 <application>psql</>'s <literal>\d</> commands</para></listitem>
<listitem><para>Fix index-corrupting bugs in /contrib/ltree
 (Teodor)</para></listitem>
<listitem><para>Numerous robustness fixes in <application>ecpg</> (Joachim
Wieland)</para></listitem>
<listitem><para>Fix backslash escaping in /contrib/dbmirror</para></listitem>
<listitem><para>Minor fixes in /contrib/dblink and /contrib/tsearch2</para>
</listitem>
<listitem><para>Efficiency improvements in hash tables and bitmap index scans
(Tom)</para></listitem>
<listitem><para>Fix instability of statistics collection on Windows (Tom, Andrew)</para></listitem>
<listitem><para>Fix <varname>statement_timeout</> to use the proper
units on Win32 (Bruce)</para>
<para>In previous Win32 8.1.X versions, the delay was off by a factor of
100.</para></listitem>
<listitem><para>Fixes for <acronym>MSVC</> and <productname>Borland C++</>
compilers (Hiroshi Saito)</para></listitem>
<listitem><para>Fixes for <systemitem class="osname">AIX</> and
<productname>Intel</> compilers (Tom)</para></listitem>
<listitem><para>Fix rare bug in continuous archiving (Tom)</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-1-4">
  <title>Release 8.1.4</title>

  <note>
  <title>Release date</title>
  <simpara>2006-05-23</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.1.3,
   including patches for extremely serious security issues.
  </para>

  <sect2>
   <title>Migration to Version 8.1.4</title>

   <para>
    A dump/restore is not required for those running 8.1.X.
    However, if you are upgrading from a version earlier than 8.1.2,
    see the release notes for 8.1.2.
   </para>

   <para>
    Full security against the SQL-injection attacks described in
    CVE-2006-2313 and CVE-2006-2314 might require changes in application
    code.  If you have applications that embed untrustworthy strings
    into SQL commands, you should examine them as soon as possible to
    ensure that they are using recommended escaping techniques.  In
    most cases, applications should be using subroutines provided by
    libraries or drivers (such as <application>libpq</>'s
    <function>PQescapeStringConn()</>) to perform string escaping,
    rather than relying on <foreignphrase>ad hoc</> code to do it.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Change the server to reject invalidly-encoded multibyte
characters in all cases (Tatsuo, Tom)</para>
<para>While <productname>PostgreSQL</> has been moving in this direction for
some time, the checks are now applied uniformly to all encodings and all
textual input, and are now always errors not merely warnings.  This change
defends against SQL-injection attacks of the type described in CVE-2006-2313.
</para></listitem>

<listitem><para>Reject unsafe uses of <literal>\'</> in string literals</para>
<para>As a server-side defense against SQL-injection attacks of the type
described in CVE-2006-2314, the server now only accepts <literal>''</> and not
<literal>\'</> as a representation of ASCII single quote in SQL string
literals.  By default, <literal>\'</> is rejected only when
<varname>client_encoding</> is set to a client-only encoding (SJIS, BIG5, GBK,
GB18030, or UHC), which is the scenario in which SQL injection is possible.
A new configuration parameter <varname>backslash_quote</> is available to
adjust this behavior when needed.  Note that full security against
CVE-2006-2314 might require client-side changes; the purpose of
<varname>backslash_quote</> is in part to make it obvious that insecure
clients are insecure.
</para></listitem>

<listitem><para>Modify <application>libpq</>'s string-escaping routines to be
aware of encoding considerations and
<varname>standard_conforming_strings</></para>
<para>This fixes <application>libpq</>-using applications for the security
issues described in CVE-2006-2313 and CVE-2006-2314, and also future-proofs
them against the planned changeover to SQL-standard string literal syntax.
Applications that use multiple <productname>PostgreSQL</> connections
concurrently should migrate to <function>PQescapeStringConn()</> and
<function>PQescapeByteaConn()</> to ensure that escaping is done correctly
for the settings in use in each database connection.  Applications that
do string escaping <quote>by hand</> should be modified to rely on library
routines instead.
</para></listitem>

<listitem><para>Fix weak key selection in pgcrypto (Marko Kreen)</para>
<para>Errors in fortuna PRNG reseeding logic could cause a predictable
session key to be selected by <function>pgp_sym_encrypt()</> in some cases.
This only affects non-OpenSSL-using builds.
</para></listitem>

<listitem><para>Fix some incorrect encoding conversion functions</para>
<para><function>win1251_to_iso</>, <function>win866_to_iso</>,
<function>euc_tw_to_big5</>, <function>euc_tw_to_mic</>,
<function>mic_to_euc_tw</> were all broken to varying
extents.
</para></listitem>

<listitem><para>Clean up stray remaining uses of <literal>\'</> in strings
(Bruce, Jan)</para></listitem>

<listitem><para>Make autovacuum visible in <structname>pg_stat_activity</>
(Alvaro)</para></listitem>

<listitem><para>Disable <literal>full_page_writes</> (Tom)</para>
<para>In certain cases, having <literal>full_page_writes</> off would cause
crash recovery to fail.  A proper fix will appear in 8.2; for now it's just
disabled.
</para></listitem>

<listitem><para>Various planner fixes, particularly for bitmap index scans and
MIN/MAX optimization (Tom)</para></listitem>

<listitem><para>Fix incorrect optimization in merge join (Tom)</para>
<para>Outer joins could sometimes emit multiple copies of unmatched rows.
</para></listitem>

<listitem><para>Fix crash from using and modifying a plpgsql function in the
same transaction</para></listitem>

<listitem><para>Fix WAL replay for case where a B-Tree index has been
truncated</para></listitem>

<listitem><para>Fix <literal>SIMILAR TO</> for patterns involving
<literal>|</> (Tom)</para></listitem>

<listitem><para>Fix <command>SELECT INTO</> and <command>CREATE TABLE AS</> to
create tables in the default tablespace, not the base directory (Kris
Jurka)</para></listitem>

<listitem><para>Fix server to use custom DH SSL parameters correctly (Michael
Fuhr)</para></listitem>

<listitem><para>Improve qsort performance (Dann Corbit)</para>
<para>Currently this code is only used on Solaris.
</para></listitem>

<listitem><para>Fix for OS/X Bonjour on x86 systems (Ashley Clark)</para></listitem>

<listitem><para>Fix various minor memory leaks</para></listitem>

<listitem><para>Fix problem with password prompting on some Win32 systems
(Robert Kinberg)</para></listitem>

<listitem><para>Improve <application>pg_dump</>'s handling of default values
for domains</para></listitem>

<listitem><para>Fix <application>pg_dumpall</> to handle identically-named
users and groups reasonably (only possible when dumping from a pre-8.1 server)
(Tom)</para>
<para>The user and group will be merged into a single role with
<literal>LOGIN</> permission.  Formerly the merged role wouldn't have
<literal>LOGIN</> permission, making it unusable as a user.
</para></listitem>

<listitem><para>Fix <application>pg_restore</> <literal>-n</> to work as
documented (Tom)</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-1-3">
  <title>Release 8.1.3</title>

  <note>
  <title>Release date</title>
  <simpara>2006-02-14</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.1.2,
   including one very serious security issue.
  </para>

  <sect2>
   <title>Migration to Version 8.1.3</title>

   <para>
    A dump/restore is not required for those running 8.1.X.
    However, if you are upgrading from a version earlier than 8.1.2,
    see the release notes for 8.1.2.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>

<listitem><para>Fix bug that allowed any logged-in user to <command>SET
ROLE</> to any other database user id (CVE-2006-0553)</para>
<para>Due to inadequate validity checking, a user could exploit the special
case that <command>SET ROLE</> normally uses to restore the previous role
setting after an error.  This allowed ordinary users to acquire superuser
status, for example.
The escalation-of-privilege risk exists only in 8.1.0-8.1.2.
However, in all releases back to 7.3 there is a related bug in <command>SET
SESSION AUTHORIZATION</> that allows unprivileged users to crash the server,
if it has been compiled with Asserts enabled (which is not the default).
Thanks to Akio Ishida for reporting this problem.
</para></listitem>

<listitem><para>Fix bug with row visibility logic in self-inserted
rows (Tom)</para>
<para>Under rare circumstances a row inserted by the current command
could be seen as already valid, when it should not be.  Repairs bug
created in 8.0.4, 7.4.9, and 7.3.11 releases.
</para></listitem>

<listitem><para>Fix race condition that could lead to <quote>file already
exists</> errors during pg_clog and pg_subtrans file creation
(Tom)</para></listitem>

<listitem><para>Fix cases that could lead to crashes if a cache-invalidation
message arrives at just the wrong time (Tom)</para></listitem>

<listitem><para>Properly check <literal>DOMAIN</> constraints for
<literal>UNKNOWN</> parameters in prepared statements
(Neil)</para></listitem>

<listitem><para>Ensure <command>ALTER COLUMN TYPE</> will process
<literal>FOREIGN KEY</>, <literal>UNIQUE</>, and <literal>PRIMARY KEY</>
constraints in the proper order (Nakano Yoshihisa)</para></listitem>

<listitem><para>Fixes to allow restoring dumps that have cross-schema
references to custom operators or operator classes (Tom)</para></listitem>

<listitem><para>Allow <application>pg_restore</> to continue properly after a
<command>COPY</> failure; formerly it tried to treat the remaining
<command>COPY</> data as SQL commands (Stephen Frost)</para></listitem>

<listitem><para>Fix <application>pg_ctl</> <literal>unregister</> crash
when the  data directory is not specified (Magnus)</para></listitem>

<listitem><para>Fix <application>libpq</> <function>PQprint</> HTML tags
(Christoph Zwerschke)</para></listitem>

<listitem><para>Fix <application>ecpg</> crash on AMD64 and PPC
(Neil)</para></listitem>

<listitem><para>Allow <literal>SETOF</> and <literal>%TYPE</> to be used
together in function result type declarations</para></listitem>

<listitem><para>Recover properly if error occurs during argument passing
in <application>PL/python</> (Neil)</para></listitem>

<listitem><para>Fix memory leak in <function>plperl_return_next</>
(Neil)</para></listitem>

<listitem><para>Fix <application>PL/perl</>'s handling of locales on
Win32 to match the backend (Andrew)</para></listitem>

<listitem><para>Various optimizer fixes (Tom)</para></listitem>

<listitem><para>Fix crash when <literal>log_min_messages</> is set to
<literal>DEBUG3</> or above in <filename>postgresql.conf</> on Win32
(Bruce)</para></listitem>

<listitem><para>Fix <application>pgxs</> <literal>-L</> library path
specification for Win32, Cygwin, OS X, AIX (Bruce)</para></listitem>

<listitem><para>Check that SID is enabled while checking for Win32 admin
privileges (Magnus)</para></listitem>

<listitem><para>Properly reject out-of-range date inputs (Kris
Jurka)</para></listitem>

<listitem><para>Portability fix for testing presence of <function>finite</>
and <function>isinf</> during configure (Tom)</para></listitem>

<listitem><para>Improve speed of <command>COPY IN</> via libpq, by
avoiding a kernel call per data line (Alon Goldshuv)</para></listitem>

<listitem><para>Improve speed of <filename>/contrib/tsearch2</> index
creation (Tom)</para></listitem>

</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-1-2">
  <title>Release 8.1.2</title>

  <note>
  <title>Release date</title>
  <simpara>2006-01-09</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.1.1.
  </para>

  <sect2>
   <title>Migration to Version 8.1.2</title>

   <para>
    A dump/restore is not required for those running 8.1.X.
    However, you might need to <command>REINDEX</> indexes on textual
    columns after updating, if you are affected by the locale or
    <application>plperl</> issues described below.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>

<listitem><para>Fix Windows code so that postmaster will continue rather
than exit if there is no more room in ShmemBackendArray (Magnus)</para>
<para>The previous behavior could lead to a denial-of-service situation if too
many connection requests arrive close together.  This applies
<emphasis>only</> to the Windows port.</para></listitem>

<listitem><para>Fix bug introduced in 8.0 that could allow ReadBuffer
to return an already-used page as new, potentially causing loss of
recently-committed data (Tom)</para></listitem>

<listitem><para>Fix for protocol-level Describe messages issued
outside a transaction or in a failed transaction (Tom)</para></listitem>

<listitem><para>Fix character string comparison for locales that consider
different character combinations as equal, such as Hungarian (Tom)</para>
<para>This might require <command>REINDEX</> to fix existing indexes on
textual columns.</para></listitem>

<listitem><para>Set locale environment variables during postmaster startup
to ensure that <application>plperl</> won't change the locale later</para>
<para>This fixes a problem that occurred if the <application>postmaster</> was
started with environment variables specifying a different locale than what
<application>initdb</> had been told.  Under these conditions, any use of
<application>plperl</> was likely to lead to corrupt indexes.  You might need
<command>REINDEX</> to fix existing indexes on
textual columns if this has happened to you.</para></listitem>

<listitem><para>Allow more flexible relocation of installation
directories (Tom)</para>
<para>Previous releases supported relocation only if all installation
directory paths were the same except for the last component.</para></listitem>

<listitem><para>Prevent crashes caused by the use of
<literal>ISO-8859-5</> and <literal>ISO-8859-9</> encodings
(Tatsuo)</para></listitem>

<listitem><para>Fix longstanding bug in strpos() and regular expression
handling in certain rarely used Asian multi-byte character sets (Tatsuo)
</para></listitem>

<listitem><para>Fix bug where COPY CSV mode considered any
<literal>\.</> to terminate the copy data</para> <para>The new code
requires <literal>\.</> to appear alone on a line, as per
documentation.</para></listitem>

<listitem><para>Make COPY CSV mode quote a literal data value of
<literal>\.</> to ensure it cannot be interpreted as the
end-of-data marker (Bruce)</para></listitem>

<listitem><para>Various fixes for functions returning <literal>RECORD</>s
(Tom) </para></listitem>

<listitem><para>Fix processing of <filename>postgresql.conf</> so a
final line with no newline is processed properly (Tom)
</para></listitem>

<listitem><para>Fix bug in <filename>/contrib/pgcrypto</> gen_salt,
which caused it not to use all available salt space for MD5 and
XDES algorithms (Marko Kreen, Solar Designer)</para>
<para>Salts for Blowfish and standard DES are unaffected.</para></listitem>

<listitem><para>Fix autovacuum crash when processing expression indexes
</para></listitem>

<listitem><para>Fix <filename>/contrib/dblink</> to throw an error,
rather than crashing, when the number of columns specified is different from
what's actually returned by the query (Joe)</para></listitem>

</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-1-1">
  <title>Release 8.1.1</title>

  <note>
  <title>Release date</title>
  <simpara>2005-12-12</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.1.0.
  </para>

  <sect2>
   <title>Migration to Version 8.1.1</title>

   <para>
    A dump/restore is not required for those running 8.1.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Fix incorrect optimizations of outer-join conditions
(Tom)</para></listitem>

<listitem><para>Fix problems with wrong reported column names in cases
involving sub-selects flattened by the optimizer (Tom)</para></listitem>

<listitem><para>Fix update failures in scenarios involving CHECK constraints,
toasted columns, <emphasis>and</> indexes (Tom)</para></listitem>

<listitem><para>Fix bgwriter problems after recovering from errors
(Tom)</para>
<para>
The background writer was found to leak buffer pins after write errors.
While not fatal in itself, this might lead to mysterious blockages of
later VACUUM commands.
</para>
</listitem>

<listitem><para>Prevent failure if client sends Bind protocol message
when current transaction is already aborted</para></listitem>

<listitem><para><filename>/contrib/tsearch2</> and <filename>/contrib/ltree</>
fixes (Teodor)</para></listitem>

<listitem><para>Fix problems with translated error messages in
languages that require word reordering, such as Turkish; also problems with
unexpected truncation of output strings and wrong display of the smallest
possible bigint value (Andrew, Tom)</para>
<para>
These problems only appeared on platforms that were using our
<filename>port/snprintf.c</> code, which includes BSD variants if
<literal>--enable-nls</> was given, and perhaps others.  In addition,
a different form of the translated-error-message problem could appear
on Windows depending on which version of <filename>libintl</> was used.
</para></listitem>

<listitem><para>Re-allow <literal>AM</>/<literal>PM</>, <literal>HH</>,
<literal>HH12</>, and <literal>D</> format specifiers for
<function>to_char(time)</> and <function>to_char(interval)</>.
(<function>to_char(interval)</> should probably use
<literal>HH24</>.) (Bruce)</para></listitem>

<listitem><para>AIX, HPUX, and MSVC compile fixes (Tom, Hiroshi
Saito)</para></listitem>

<listitem><para>Optimizer improvements (Tom)</para></listitem>

<listitem><para>Retry file reads and writes after Windows
NO_SYSTEM_RESOURCES error (Qingqing Zhou)</para></listitem>

<listitem><para>Prevent <application>autovacuum</> from crashing during
ANALYZE of expression index (Alvaro)</para></listitem>

<listitem><para>Fix problems with ON COMMIT DELETE ROWS temp
tables</para></listitem>

<listitem><para>Fix problems when a trigger alters the output of a SELECT
DISTINCT query</para></listitem>

<listitem><para>Add 8.1.0 release note item on how to migrate invalid
<literal>UTF-8</> byte sequences (Paul Lindner)</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-1">
  <title>Release 8.1</title>

  <note>
   <title>Release date</title>
   <simpara>2005-11-08</simpara>
  </note>

  <sect2>
   <title>Overview</title>

   <para>
    Major changes in this release:
   </para>

   <variablelist>

    <varlistentry>
     <term>
      Improve concurrent access to the shared buffer cache (Tom)
     </term>

     <listitem>
      <para>
       Access to the shared buffer cache was identified as a
       significant scalability problem, particularly on multi-CPU
       systems. In this release, the way that locking is done in the
       buffer manager has been overhauled to reduce lock contention
       and improve scalability. The buffer manager has also been
       changed to use a <quote>clock sweep</quote> replacement
       policy.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Allow index scans to use an intermediate in-memory bitmap (Tom)
     </term>

     <listitem>
      <para>
       In previous releases, only a single index could be used to do
       lookups on a table. With this feature, if a query has
       <command>WHERE tab.col1 = 4 and tab.col2 = 9</>, and there is
       no multicolumn index on <literal>col1</> and <literal>col2</>,
       but there is an index on <literal>col1</> and another on
       <literal>col2</>, it is possible to search both indexes and
       combine the results in memory, then do heap fetches for only
       the rows matching both the <literal>col1</> and
       <literal>col2</> restrictions. This is very useful in
       environments that have a lot of unstructured queries where it
       is impossible to create indexes that match all possible access
       conditions.  Bitmap scans are useful even with a single index,
       as they reduce the amount of random access needed; a bitmap
       index scan is efficient for retrieving fairly large fractions
       of the complete table, whereas plain index scans are not.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Add two-phase commit (Heikki Linnakangas, Alvaro, Tom)
     </term>

     <listitem>
      <para>
       Two-phase commit allows transactions to be "prepared" on several
       computers, and once all computers have successfully prepared
       their transactions (none failed), all transactions can be
       committed. Even if a machine crashes after a prepare, the
       prepared transaction can be committed after the machine is
       restarted. New syntax includes <command>PREPARE TRANSACTION</> and
       <command>COMMIT/ROLLBACK PREPARED</>. A new system view
       <literal>pg_prepared_xacts</> has also been added.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Create a new role system that replaces users and groups
      (Stephen Frost)
     </term>

     <listitem>
      <para>
       Roles are a combination of users and groups. Like users, they
       can have login capability, and like groups, a role can have
       other roles as members. Roles basically remove the distinction
       between users and groups. For example, a role can:
      </para>

      <itemizedlist>

       <listitem>
        <para>
          Have login capability (optionally)
        </para>
       </listitem>

       <listitem>
        <para>
         Own objects
        </para>
       </listitem>

       <listitem>
        <para>
         Hold access permissions for database objects
        </para>
       </listitem>

       <listitem>
        <para>
         Inherit permissions from other roles it is a member of
        </para>
       </listitem>

      </itemizedlist>
      <para>
       Once a user logs into a role, she obtains capabilities of
       the login role plus any inherited roles, and can use
       <command>SET ROLE</> to switch to other roles she is a member of.
       This feature is a generalization of the SQL standard's concept of
       roles.
       This change also replaces <structname>pg_shadow</> and
       <structname>pg_group</> by new role-capable catalogs
       <structname>pg_authid</> and <structname>pg_auth_members</>. The old
       tables are redefined as read-only views on the new role tables.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Automatically use indexes for <function>MIN()</> and
      <function>MAX()</> (Tom)
     </term>

     <listitem>
      <para>
       In previous releases, the only way to use an index for
       <function>MIN()</> or <function>MAX()</> was to rewrite the
       query as <command>SELECT col FROM tab ORDER BY col LIMIT 1</>.
       Index usage now happens automatically.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Move <filename>/contrib/pg_autovacuum</> into the main server
      (Alvaro)
     </term>

     <listitem>
      <para>
       Integrating autovacuum into the server allows it to be
       automatically started and stopped in sync with the database
       server, and allows autovacuum to be configured from
       <filename>postgresql.conf</>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Add shared row level locks using <command>SELECT ... FOR SHARE</>
      (Alvaro)
     </term>

     <listitem>
      <para>
       While <productname>PostgreSQL</productname>'s MVCC locking
       allows <command>SELECT</> to never be blocked by writers and
       therefore does not need shared row locks for typical operations,
       shared locks are useful for applications that require shared row
       locking.  In particular this reduces the locking requirements
       imposed by referential integrity checks.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Add dependencies on shared objects, specifically roles
      (Alvaro)
     </term>

     <listitem>
      <para>
       This extension of the dependency mechanism prevents roles from
       being dropped while there are still database objects they own.
       Formerly it was possible to accidentally <quote>orphan</> objects by
       deleting their owner.  While this could be recovered from, it
       was messy and unpleasant.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Improve performance for partitioned tables (Simon)
     </term>

     <listitem>
      <para>
       The new <varname>constraint_exclusion</varname> configuration
       parameter avoids lookups on child tables where constraints indicate
       that no matching rows exist in the child table.
      </para>
      <para>
       This allows for a basic type of table partitioning. If child tables
       store separate key ranges and this is enforced using appropriate
       <command>CHECK</> constraints, the optimizer will skip child
       table accesses when the constraint guarantees no matching rows
       exist in the child table.
      </para>
     </listitem>
    </varlistentry>

   </variablelist>
  </sect2>

  <sect2>
   <title>Migration to Version 8.1</title>

   <para>
    A dump/restore using <application>pg_dump</application> is required
    for those wishing to migrate data from any previous release.
   </para>

   <para>
    The 8.0 release announced that the <function>to_char()</> function
    for intervals would be removed in 8.1. However, since no better API
    has been suggested, <function>to_char(interval)</> has been enhanced in
    8.1 and will remain in the server.
   </para>

   <para>
    Observe the following incompatibilities:
   </para>

   <itemizedlist>

    <listitem>
     <para>
      <varname>add_missing_from</> is now false by default (Neil)
     </para>
     <para>
      By default, we now generate an error if a table is used in a query
      without a <literal>FROM</> reference.  The old behavior is still
      available, but the parameter must be set to 'true' to obtain it.
     </para>

     <para>
      It might be necessary to set <varname>add_missing_from</> to true
      in order to load an existing dump file, if the dump contains any
      views or rules created using the implicit-<literal>FROM</> syntax.
      This should be a one-time annoyance, because
      <productname>PostgreSQL</productname> 8.1 will convert
      such views and rules to standard explicit-<literal>FROM</> syntax.
      Subsequent dumps will therefore not have the problem.
     </para>
    </listitem>

    <listitem>
     <para>
      Cause input of a zero-length string (<literal>''</literal>) for
      <type>float4</type>/<type>float8</type>/<type>oid</type>
      to throw an error, rather than treating it as a zero (Neil)
     </para>
     <para>
      This change is consistent with the current handling of
      zero-length strings for integers. The schedule for this change
      was announced in 8.0.
     </para>
    </listitem>

    <listitem>
     <para>
      <varname>default_with_oids</> is now false by default (Neil)
     </para>
     <para>
      With this option set to false, user-created tables no longer
      have an OID column unless <command>WITH OIDS</> is specified in
      <command>CREATE TABLE</>. Though OIDs have existed in all
      releases of <productname>PostgreSQL</>, their use is limited
      because they are only four bytes long and the counter is shared
      across all installed databases. The preferred way of uniquely
      identifying rows is via sequences and the <type>SERIAL</> type,
      which have been supported since <productname>PostgreSQL</> 6.4.
     </para>
    </listitem>

    <listitem>
     <para>
      Add <literal>E''</> syntax so eventually ordinary strings can
      treat backslashes literally (Bruce)
     </para>
     <para>
      Currently <productname>PostgreSQL</productname> processes a
      backslash in a string literal as introducing a special escape sequence,
      e.g. <literal>\n</> or <literal>\010</>.
      While this allows easy entry of special values, it is
      nonstandard and makes porting of applications from other
      databases more difficult. For this reason, the
      <productname>PostgreSQL</productname> project is planning to
      remove the special meaning of backslashes in strings. For
      backward compatibility and for users who want special backslash
      processing, a new string syntax has been created. This new string
      syntax is formed by writing an <literal>E</> immediately preceding the
      single quote that starts the string, e.g. <literal>E'hi\n'</>. While
      this release does not change the handling of backslashes in strings, it
      does add new configuration parameters to help users migrate applications
      for future releases:
     </para>
     <itemizedlist>

      <listitem>
       <para>
        <varname>standard_conforming_strings</> &mdash; does this release
        treat backslashes literally in ordinary strings?
       </para>
      </listitem>

      <listitem>
      <para>
       <varname>escape_string_warning</> &mdash; warn about backslashes in
       ordinary (non-E) strings
      </para>
     </listitem>

     </itemizedlist>

     <para>
      The <varname>standard_conforming_strings</> value is read-only.
      Applications can retrieve the value to know how backslashes are
      processed.  (Presence of the parameter can also be taken as an
      indication that <literal>E''</> string syntax is supported.)
      In a future release, <varname>standard_conforming_strings</>
      will be true, meaning backslashes will be treated literally in
      non-E strings. To prepare for this change, use <literal>E''</>
      strings in places that need special backslash processing, and
      turn on <varname>escape_string_warning</> to find additional
      strings that need to be converted to use <literal>E''</>.
      Also, use two single-quotes (<literal>''</>) to embed a literal
      single-quote in a string, rather than the
      <productname>PostgreSQL</productname>-supported syntax of
      backslash single-quote (<literal>\'</>).  The former is
      standards-conforming and does not require the use of the
      <literal>E''</> string syntax.  You can also use the
      <literal>$$</> string syntax, which does not treat backslashes
      specially.
     </para>
    </listitem>

    <listitem>
     <para>
      Make <command>REINDEX DATABASE</> reindex all indexes in the
      database (Tom)
     </para>
     <para>
      Formerly, <command>REINDEX DATABASE</> reindexed only
      system tables. This new behavior seems more intuitive. A new
      command <command>REINDEX SYSTEM</> provides the old functionality
      of reindexing just the system tables.
     </para>
    </listitem>

    <listitem>
     <para>
      Read-only large object descriptors now obey MVCC snapshot semantics
     </para>
     <para>
      When a large object is opened with <literal>INV_READ</> (and not
      <literal>INV_WRITE</>), the data read from the descriptor will now
      reflect a <quote>snapshot</> of the large object's state at the
      time of the transaction snapshot in use by the query that called
      <function>lo_open()</>.  To obtain the old behavior of always
      returning the latest committed data, include <literal>INV_WRITE</>
      in the mode flags for <function>lo_open()</>.
     </para>
    </listitem>

    <listitem>
     <para>
      Add proper dependencies for arguments of sequence functions (Tom)
     </para>
     <para>
      In previous releases, sequence names passed to <function>nextval()</>,
      <function>currval()</>, and <function>setval()</> were stored as
      simple text strings, meaning that renaming or dropping a
      sequence used in a <literal>DEFAULT</> clause made the clause
      invalid. This release stores all newly-created sequence function
      arguments as internal OIDs, allowing them to track sequence
      renaming, and adding dependency information that prevents
      improper sequence removal. It also makes such <literal>DEFAULT</>
      clauses immune to schema renaming and search path changes.
     </para>
     <para>
      Some applications might rely on the old behavior of
      run-time lookup for sequence names. This can still be done by
      explicitly casting the argument to <type>text</>, for example
      <literal>nextval('myseq'::text)</>.
     </para>
     <para>
      Pre-8.1 database dumps loaded into 8.1 will use the old text-based
      representation and therefore will not have the features of
      OID-stored arguments. However, it is possible to update a
      database containing text-based <literal>DEFAULT</> clauses.
      First, save this query into a file, such as <filename>fixseq.sql</>:
<programlisting>
SELECT  'ALTER TABLE ' ||
   pg_catalog.quote_ident(n.nspname) || '.' ||
   pg_catalog.quote_ident(c.relname) ||
   ' ALTER COLUMN ' || pg_catalog.quote_ident(a.attname) ||
   ' SET DEFAULT ' ||
   regexp_replace(d.adsrc,
                  $$val\(\(('[^']*')::text\)::regclass$$,
                  $$val(\1$$,
                  'g') ||
   ';'
FROM    pg_namespace n, pg_class c, pg_attribute a, pg_attrdef d
WHERE   n.oid = c.relnamespace AND
   c.oid = a.attrelid AND
   a.attrelid = d.adrelid AND
   a.attnum = d.adnum AND
   d.adsrc ~ $$val\(\('[^']*'::text\)::regclass$$;
</programlisting>
      Next, run the query against a database to find what
      adjustments are required, like this for database <literal>db1</>:
<programlisting>
psql -t -f fixseq.sql db1
</programlisting>
      This will show the <command>ALTER TABLE</> commands needed to
      convert the database to the newer OID-based representation.
      If the commands look reasonable, run this to update the database:
<programlisting>
psql -t -f fixseq.sql db1 | psql -e db1
</programlisting>
      This process must be repeated in each database to be updated.
     </para>
    </listitem>

    <listitem>
     <para>
      In <application>psql</application>, treat unquoted
      <literal>\{digit}+</> sequences as octal (Bruce)
     </para>
     <para>
      In previous releases, <literal>\{digit}+</> sequences were
      treated as decimal, and only <literal>\0{digit}+</> were treated
      as octal. This change was made for consistency.
     </para>
    </listitem>

    <listitem>
     <para>
      Remove grammar productions for prefix and postfix <literal>%</>
      and <literal>^</> operators
      (Tom)
     </para>
     <para>
      These have never been documented and complicated the use of the
      modulus operator (<literal>%</>) with negative numbers.
     </para>
    </listitem>

    <listitem>
     <para>
      Make <literal>&amp;&lt;</> and <literal>&amp;&gt;</> for polygons
      consistent with the box "over" operators (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      <command>CREATE LANGUAGE</> can ignore the provided arguments
      in favor of information from <structname>pg_pltemplate</>
      (Tom)
     </para>
     <para>
      A new system catalog <structname>pg_pltemplate</> has been defined
      to carry information about the preferred definitions of procedural
      languages (such as whether they have validator functions).  When
      an entry exists in this catalog for the language being created,
      <command>CREATE LANGUAGE</> will ignore all its parameters except the
      language name and instead use the catalog information.  This measure
      was taken because of increasing problems with obsolete language
      definitions being loaded by old dump files.  As of 8.1,
      <application>pg_dump</> will dump procedural language definitions as
      just <command>CREATE LANGUAGE <replaceable>name</></command>, relying
      on a template entry to exist at load time.  We expect this will be a
      more future-proof representation.
     </para>
    </listitem>

    <listitem>
     <para>
      Make <function>pg_cancel_backend(int)</function> return a
      <type>boolean</type> rather than an <type>integer</type> (Neil)
     </para>
    </listitem>

    <listitem>
     <para>
      Some users are having problems loading UTF-8 data into 8.1.X.
      This is because previous versions allowed invalid UTF-8 byte
      sequences to be entered into the database, and this release
      properly accepts only valid UTF-8 sequences. One way to correct a
      dumpfile is to run the command <command>iconv -c -f UTF-8 -t
      UTF-8 -o cleanfile.sql dumpfile.sql</>. The <literal>-c</> option
      removes invalid character sequences. A diff of the two files will
      show the sequences that are invalid. <command>iconv</> reads the
      entire input file into memory so it might be necessary to use
      <application>split</> to break up the dump into multiple smaller
      files for processing.
     </para>
    </listitem>

   </itemizedlist>
  </sect2>

  <sect2>
   <title>Additional Changes</title>

   <para>
    Below you will find a detailed account of the additional changes
    between <productname>PostgreSQL</productname> 8.1 and the
    previous major release.
   </para>

   <sect3>
    <title>Performance Improvements</title>
    <itemizedlist>

     <listitem>
      <para>
       Improve GiST and R-tree index performance (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve the optimizer, including auto-resizing of hash joins
       (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Overhaul internal API in several areas
      </para>
     </listitem>

     <listitem>
      <para>
       Change WAL record CRCs from 64-bit to 32-bit (Tom)
      </para>
      <para>
       We determined that the extra cost of computing 64-bit CRCs was
       significant, and the gain in reliability too marginal to justify it.
      </para>
     </listitem>

     <listitem>
      <para>
       Prevent writing large empty gaps in WAL pages (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve spinlock behavior on SMP machines, particularly Opterons (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow nonconsecutive index columns to be used in a multicolumn
       index (Tom)
      </para>
      <para>
       For example, this allows an index on columns a,b,c to be used in
       a query with <command>WHERE a = 4 and c = 10</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Skip WAL logging for <command>CREATE TABLE AS</> /
       <command>SELECT INTO</> (Simon)
      </para>
      <para>
       Since a crash during <command>CREATE TABLE AS</> would cause the
       table to be dropped during recovery, there is no reason to WAL
       log as the table is loaded.  (Logging still happens if WAL
       archiving is enabled, however.)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow concurrent GiST index access (Teodor, Oleg)
      </para>
     </listitem>

     <listitem>
      <para>
       Add configuration parameter <varname>full_page_writes</> to
       control writing full pages to WAL (Bruce)
      </para>
      <para>
       To prevent partial disk writes from corrupting the database,
       <productname>PostgreSQL</productname> writes a complete copy of
       each database disk page to WAL the first time it is modified
       after a checkpoint. This option turns off that functionality for more
       speed.  This is safe to use with battery-backed disk caches where
       partial page writes cannot happen.
      </para>
     </listitem>

     <listitem>
      <para>
       Use <literal>O_DIRECT</> if available when using
       <literal>O_SYNC</> for <varname>wal_sync_method</varname>
       (Itagaki Takahiro)
      </para>
      <para>
       <literal>O_DIRECT</> causes disk writes to bypass the kernel
       cache, and for WAL writes, this improves performance.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve <command>COPY FROM</> performance (Alon Goldshuv)
      </para>
      <para>
       This was accomplished by reading <command>COPY</> input in
       larger chunks, rather than character by character.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve the performance of <function>COUNT()</function>,
       <function>SUM</function>, <function>AVG()</function>,
       <function>STDDEV()</function>, and
       <function>VARIANCE()</function> (Neil, Tom)
      </para>
     </listitem>
    </itemizedlist>
   </sect3>

   <sect3>
    <title>Server Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Prevent problems due to transaction ID (XID) wraparound (Tom)
      </para>
      <para>
       The server will now warn when the transaction counter approaches
       the wraparound point.  If the counter becomes too close to wraparound,
       the server will stop accepting queries.  This ensures that data is
       not lost before needed vacuuming is performed.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix problems with object IDs (OIDs) conflicting with existing system
       objects after the OID counter has wrapped around (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add warning about the need to increase
       <varname>max_fsm_relations</> and <varname>max_fsm_pages</>
       during <command>VACUUM</> (Ron Mayer)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <varname>temp_buffers</> configuration parameter to allow
       users to determine the size of the local buffer area for
       temporary table access (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add session start time and client IP address to
       <literal>pg_stat_activity</> (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Adjust <literal>pg_stat</> views for bitmap scans (Tom)
      </para>
      <para>
       The meanings of some of the fields have changed slightly.
      </para>
     </listitem>

     <listitem>
      <para>
       Enhance <literal>pg_locks</> view (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Log queries for client-side <command>PREPARE</> and
       <command>EXECUTE</> (Simon)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow Kerberos name and user name case sensitivity to be
       specified in <filename>postgresql.conf</> (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Add configuration parameter <varname>krb_server_hostname</> so
       that the server host name can be specified as part of service
       principal (Todd Kover)
      </para>
      <para>
       If not set, any service principal matching an entry in the
       keytab can be used. This is new Kerberos matching behavior in
       this release.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <varname>log_line_prefix</> options for millisecond
       timestamps (<literal>%m</>) and remote host (<literal>%h</>) (Ed
       L.)
      </para>
     </listitem>

     <listitem>
      <para>
       Add WAL logging for GiST indexes (Teodor, Oleg)
      </para>
      <para>
       GiST indexes are now safe for crash and point-in-time recovery.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove old <filename>*.backup</> files when we do
       <function>pg_stop_backup()</> (Bruce)
      </para>
      <para>
       This prevents a large number of <filename>*.backup</> files from
       existing in <filename>pg_xlog/</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add configuration parameters to control TCP/IP keep-alive
       times for idle, interval, and count (Oliver Jowett)
      </para>

      <para>
       These values can be changed to allow more rapid detection of
       lost client connections.
      </para>
     </listitem>

     <listitem>
      <para>
       Add per-user and per-database connection limits (Petr Jelinek)
      </para>
      <para>
       Using <command>ALTER USER</> and <command>ALTER DATABASE</>,
       limits can now be enforced on the maximum number of sessions that
       can concurrently connect as a specific user or to a specific database.
       Setting the limit to zero disables user or database connections.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow more than two gigabytes of shared memory and per-backend
       work memory on 64-bit machines (Koichi Suzuki)
      </para>
     </listitem>

     <listitem>
      <para>
       New system catalog <structname>pg_pltemplate</> allows overriding
       obsolete procedural-language definitions in dump files (Tom)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>Query Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add temporary views (Koju Iijima, Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <command>HAVING</> without any aggregate functions or
       <command>GROUP BY</> so that the query returns a single group (Tom)
      </para>
      <para>
       Previously, such a case would treat the <command>HAVING</>
       clause the same as a <command>WHERE</> clause.  This was not per spec.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <command>USING</> clause to allow additional tables to be
       specified to <command>DELETE</> (Euler Taveira de Oliveira, Neil)
      </para>
      <para>
       In prior releases, there was no clear method for specifying
       additional tables to be used for joins in a <command>DELETE</>
       statement. <command>UPDATE</> already has a <literal>FROM</>
       clause for this purpose.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for <literal>\x</> hex escapes in backend and ecpg
       strings (Bruce)
      </para>
      <para>
       This is just like the standard C <literal>\x</> escape syntax.
       Octal escapes were already supported.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <command>BETWEEN SYMMETRIC</> query syntax (Pavel Stehule)
      </para>
      <para>
       This feature allows <command>BETWEEN</> comparisons without
       requiring the first value to be less than the second. For
       example, <command>2 BETWEEN [ASYMMETRIC] 3 AND 1</> returns
       false, while <command>2 BETWEEN SYMMETRIC 3 AND 1</> returns
       true. <command>BETWEEN ASYMMETRIC</> was already supported.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <command>NOWAIT</> option to <command>SELECT ... FOR
       UPDATE/SHARE</> (Hans-Juergen Schoenig)
      </para>
      <para>
       While the <varname>statement_timeout</> configuration
       parameter allows a query taking more than a certain amount of
       time to be cancelled, the <command>NOWAIT</> option allows a
       query to be canceled as soon as a <command>SELECT ... FOR
       UPDATE/SHARE</> command cannot immediately acquire a row lock.
      </para>
     </listitem>
    </itemizedlist>
   </sect3>


   <sect3>
    <title>Object Manipulation Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Track dependencies of shared objects (Alvaro)
      </para>
      <para>
       <productname>PostgreSQL</productname> allows global tables
       (users, databases, tablespaces) to reference information in
       multiple databases. This addition adds dependency information
       for global tables, so, for example, user ownership can be
       tracked across databases, so a user who owns something in any
       database can no longer be removed. Dependency tracking already
       existed for database-local objects.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow limited <command>ALTER OWNER</> commands to be performed
       by the object owner (Stephen Frost)
      </para>
      <para>
       Prior releases allowed only superusers to change object owners.
       Now, ownership can be transferred if the user executing the command
       owns the object and would be able to create it as the new owner
       (that is, the user is a member of the new owning role and that role
       has the CREATE permission that would be needed to create the object
       afresh).
      </para>
     </listitem>

     <listitem>
      <para>
       Add <command>ALTER</> object <command>SET SCHEMA</> capability
       for some object types (tables, functions, types) (Bernd Helmle)
      </para>
      <para>
       This allows objects to be moved to different schemas.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <command>ALTER TABLE ENABLE/DISABLE TRIGGER</command> to
       disable triggers (Satoshi Nagayasu)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>Utility Command Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Allow <command>TRUNCATE</> to truncate multiple tables in a
       single command (Alvaro)
      </para>
      <para>
       Because of referential integrity checks, it is not allowed to
       truncate a table that is part of a referential integrity
       constraint. Using this new functionality, <command>TRUNCATE</>
       can be used to truncate such tables, if both tables involved in
       a referential integrity constraint are truncated in a single
       <command>TRUNCATE</> command.
      </para>
     </listitem>

     <listitem>
      <para>
       Properly process carriage returns and line feeds in
       <command>COPY CSV</> mode (Andrew)
      </para>
      <para>
       In release 8.0, carriage returns and line feeds in <command>CSV
       COPY TO</> were processed in an inconsistent manner. (This was
       documented on the TODO list.)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <command>COPY WITH CSV HEADER</> to allow a header line as
       the first line in <command>COPY</> (Andrew)
      </para>
      <para>
       This allows handling of the common <command>CSV</> usage of
       placing the column names on the first line of the data file. For
       <command>COPY TO</>, the first line contains the column names,
       and for <command>COPY FROM</>, the first line is ignored.
      </para>
     </listitem>

     <listitem>
      <para>
       On Windows, display better sub-second precision in
       <command>EXPLAIN ANALYZE</> (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Add trigger duration display to <command>EXPLAIN ANALYZE</>
       (Tom)
      </para>
      <para>
       Prior releases included trigger execution time as part of the
       total execution time, but did not show it separately.  It is now
       possible to see how much time is spent in each trigger.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for <literal>\x</> hex escapes in <command>COPY</>
       (Sergey Ten)
      </para>
      <para>
       Previous releases only supported octal escapes.
      </para>
     </listitem>

     <listitem>
      <para>
       Make <command>SHOW ALL</> include variable descriptions
       (Matthias Schmidt)
      </para>
      <para>
       <command>SHOW</> varname still only displays the variable's
       value and does not include the description.
      </para>
     </listitem>

     <listitem>
      <para>
       Make <application>initdb</application> create a new standard
       database called <literal>postgres</>, and convert utilities to
       use <literal>postgres</> rather than <literal>template1</> for
       standard lookups (Dave)
      </para>
      <para>
       In prior releases, <literal>template1</> was used both as a
       default connection for utilities like
       <application>createuser</application>, and as a template for
       new databases. This caused <command>CREATE DATABASE</> to
       sometimes fail, because a new database cannot be created if
       anyone else is in the template database. With this change, the
       default connection database is now <literal>postgres</>,
       meaning it is much less likely someone will be using
       <literal>template1</> during <command>CREATE DATABASE</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Create new <application>reindexdb</application> command-line
       utility by moving <filename>/contrib/reindexdb</> into the
       server (Euler Taveira de Oliveira)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>Data Type and Function Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add <function>MAX()</> and <function>MIN()</> aggregates for
       array types (Koju Iijima)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <function>to_date()</> and <function>to_timestamp()</> to
       behave reasonably when <literal>CC</> and <literal>YY</> fields
       are both used (Karel Zak)
      </para>
      <para>
       If the format specification contains <literal>CC</> and a year
       specification is <literal>YYY</> or longer, ignore the
       <literal>CC</>. If the year specification is <literal>YY</> or
       shorter, interpret <literal>CC</> as the previous century.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>md5(bytea)</> (Abhijit Menon-Sen)
      </para>
      <para>
       <function>md5(text)</> already existed.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for <command>numeric ^ numeric</> based on
       <function>power(numeric, numeric)</>
      </para>
      <para>
       The function already existed, but there was no operator assigned
       to it.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <type>NUMERIC</> modulus by properly truncating the quotient
       during computation (Bruce)
      </para>
      <para>
       In previous releases, modulus for large values sometimes
       returned negative results due to rounding of the quotient.
      </para>
     </listitem>

     <listitem>
      <para>
       Add a function <function>lastval()</> (Dennis Bj&ouml;rklund)
      </para>
      <para>
       <function>lastval()</> is a simplified version of
       <function>currval()</>. It automatically determines the proper
       sequence name based on the most recent <function>nextval()</> or
       <function>setval()</> call performed by the current session.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>to_timestamp(DOUBLE PRECISION) (Michael Glaesemann)</>
      </para>
      <para>
       Converts Unix seconds since 1970 to a <type>TIMESTAMP WITH
       TIMEZONE</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>pg_postmaster_start_time()</> function (Euler
       Taveira de Oliveira, Matthias Schmidt)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow the full use of time zone names in <command>AT TIME
       ZONE</>, not just the short list previously available (Magnus)
      </para>
      <para>
       Previously, only a predefined list of time zone names were
       supported by <command>AT TIME ZONE</>. Now any supported time
       zone name can be used, e.g.:
       <programlisting>
        SELECT CURRENT_TIMESTAMP AT TIME ZONE 'Europe/London';
       </programlisting>
       In the above query, the time zone used is adjusted based on the
       daylight saving time rules that were in effect on the supplied
       date.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>GREATEST()</> and <function>LEAST()</> variadic
       functions (Pavel Stehule)
      </para>
      <para>
       These functions take a variable number of arguments and return
       the greatest or least value among the arguments.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>pg_column_size()</> (Mark Kirkwood)
      </para>
      <para>
       This returns storage size of a column, which might be compressed.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>regexp_replace()</> (Atsushi Ogawa)
      </para>
      <para>
       This allows regular expression replacement, like sed. An optional
       flag argument allows selection of global (replace all) and
       case-insensitive modes.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix interval division and multiplication (Bruce)
      </para>
      <para>
       Previous versions sometimes returned unjustified results, like
       <command>'4 months'::interval / 5</> returning <command>'1 mon
       -6 days'</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix roundoff behavior in timestamp, time, and interval output (Tom)
      </para>
      <para>
       This fixes some cases in which the seconds field would be shown as
       <literal>60</> instead of incrementing the higher-order fields.
      </para>
     </listitem>

     <listitem>
      <para>
       Add a separate day field to type <type>interval</> so a one day
       interval can be distinguished from a 24 hour interval (Michael
       Glaesemann)
      </para>
      <para>
       Days that contain a daylight saving time adjustment are not 24
       hours long, but typically 23 or 25 hours.  This change creates a
       conceptual distinction between intervals of <quote>so many days</>
       and intervals of <quote>so many hours</>.  Adding
       <literal>1 day</> to a timestamp now gives the same local time on
       the next day even if a daylight saving time adjustment occurs
       between, whereas adding <literal>24 hours</> will give a different
       local time when this happens.  For example, under US DST rules:
       <programlisting>
        '2005-04-03 00:00:00-05' + '1 day' = '2005-04-04 00:00:00-04'
        '2005-04-03 00:00:00-05' + '24 hours' = '2005-04-04 01:00:00-04'
       </programlisting>
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>justify_days()</> and <function>justify_hours()</>
       (Michael Glaesemann)
      </para>
      <para>
       These functions, respectively, adjust days to an appropriate
       number of full months and days, and adjust hours to an
       appropriate number of full days and hours.
      </para>
     </listitem>

     <listitem>
      <para>
       Move <filename>/contrib/dbsize</> into the backend, and rename
       some of the functions (Dave Page, Andreas Pflug)
      </para>
      <para>
       <itemizedlist>

        <listitem>
         <para>
           <function>pg_tablespace_size()</>
         </para>
        </listitem>

        <listitem>
         <para>
          <function>pg_database_size()</>
         </para>
        </listitem>

        <listitem>
         <para>
          <function>pg_relation_size()</>
         </para>
        </listitem>

        <listitem>
         <para>
          <function>pg_total_relation_size()</>
         </para>
        </listitem>

        <listitem>
         <para>
          <function>pg_size_pretty()</>
         </para>
        </listitem>

       </itemizedlist>
      </para>
      <para>
       <function>pg_total_relation_size()</> includes indexes and TOAST
       tables.
      </para>
     </listitem>

     <listitem>
      <para>
       Add functions for read-only file access to the cluster directory
       (Dave Page, Andreas Pflug)
      </para>
      <para>
       <itemizedlist>

        <listitem>
         <para>
          <function>pg_stat_file()</>
         </para>
        </listitem>

        <listitem>
         <para>
          <function>pg_read_file()</>
         </para>
        </listitem>

        <listitem>
         <para>
          <function>pg_ls_dir()</>
         </para>
        </listitem>

       </itemizedlist>
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>pg_reload_conf()</> to force reloading of the
       configuration files (Dave Page, Andreas Pflug)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>pg_rotate_logfile()</> to force rotation of the
       server log file (Dave Page, Andreas Pflug)
      </para>
     </listitem>

     <listitem>
      <para>
       Change <literal>pg_stat_*</> views to include TOAST tables (Tom)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>Encoding and Locale Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Rename some encodings to be more consistent and to follow
       international standards (Bruce)
      </para>
      <para>
       <itemizedlist>

        <listitem>
         <para>
          <literal>UNICODE</> is now <literal>UTF8</>
         </para>
        </listitem>

        <listitem>
         <para>
          <literal>ALT</> is now <literal>WIN866</>
         </para>
        </listitem>

        <listitem>
         <para>
          <literal>WIN</> is now <literal>WIN1251</>
         </para>
        </listitem>

        <listitem>
         <para>
         <literal>TCVN</> is now <literal>WIN1258</>
         </para>
        </listitem>

       </itemizedlist>
      </para>

      <para>
       The original names still work.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for <literal>WIN1252</> encoding (Roland Volkmann)
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for four-byte <literal>UTF8</> characters (John
       Hansen)
      </para>
      <para>
       Previously only one, two, and three-byte <literal>UTF8</> characters
       were supported. This is particularly important for support for
       some Chinese character sets.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow direct conversion between <literal>EUC_JP</> and
       <literal>SJIS</> to improve performance (Atsushi Ogawa)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow the UTF8 encoding to work on Windows (Magnus)
      </para>
      <para>
       This is done by mapping UTF8 to the Windows-native UTF16
       implementation.
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>General Server-Side Language Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Fix <command>ALTER LANGUAGE RENAME</> (Sergey Yatskevich)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow function characteristics, like strictness and volatility,
       to be modified via <command>ALTER FUNCTION</> (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Increase the maximum number of function arguments to 100 (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow SQL and PL/PgSQL functions to use <command>OUT</> and
       <command>INOUT</> parameters (Tom)
      </para>
      <para>
       <command>OUT</> is an alternate way for a function to return
       values. Instead of using <command>RETURN</>, values can be
       returned by assigning to parameters declared as <command>OUT</> or
       <command>INOUT</>.  This is notationally simpler in some cases,
       particularly so when multiple values need to be returned.
       While returning multiple values from a function
       was possible in previous releases, this greatly simplifies the
       process.  (The feature will be extended to other server-side
       languages in future releases.)
      </para>
     </listitem>

     <listitem>
      <para>
       Move language handler functions into the <literal>pg_catalog</> schema
      </para>
      <para>
       This makes it easier to drop the public schema if desired.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>SPI_getnspname()</function> to SPI (Neil)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>

   <sect3>
    <title>PL/PgSQL Server-Side Language Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Overhaul the memory management of PL/PgSQL functions (Neil)
      </para>
      <para>
       The parsetree of each function is now stored in a separate
       memory context. This allows this memory to be easily reclaimed
       when it is no longer needed.
      </para>
     </listitem>

     <listitem>
      <para>
       Check function syntax at <command>CREATE FUNCTION</> time,
       rather than at runtime (Neil)
      </para>
      <para>
       Previously, most syntax errors were reported only when the
       function was executed.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <command>OPEN</> to open non-<command>SELECT</> queries
       like <command>EXPLAIN</> and <command>SHOW</> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       No longer require functions to issue a <command>RETURN</>
       statement (Tom)
      </para>
      <para>
       This is a byproduct of the newly added <command>OUT</> and
       <command>INOUT</> functionality.  <command>RETURN</> can
       be omitted when it is not needed to provide the function's
       return value.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for an optional <command>INTO</> clause to
       PL/PgSQL's <command>EXECUTE</> statement (Pavel Stehule, Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <command>CREATE TABLE AS</> set <command>ROW_COUNT</> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Define <literal>SQLSTATE</> and <literal>SQLERRM</> to return
       the <literal>SQLSTATE</> and error message of the current
       exception (Pavel Stehule, Neil)
      </para>
      <para>
       These variables are only defined inside exception blocks.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow the parameters to the <command>RAISE</> statement to be
       expressions (Pavel Stehule, Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Add a loop <command>CONTINUE</> statement (Pavel Stehule, Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow block and loop labels (Pavel Stehule)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>PL/Perl Server-Side Language Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Allow large result sets to be returned efficiently (Abhijit
       Menon-Sen)
      </para>
      <para>
       This allows functions to use <function>return_next()</> to avoid
       building the entire result set in memory.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow one-row-at-a-time retrieval of query results (Abhijit Menon-Sen)
      </para>
      <para>
       This allows functions to use <function>spi_query()</> and
       <function>spi_fetchrow()</> to avoid accumulating the entire
       result set in memory.
      </para>
     </listitem>

     <listitem>
      <para>
       Force PL/Perl to handle strings as <literal>UTF8</> if the
       server encoding is <literal>UTF8</> (David Kamholz)
      </para>
     </listitem>

     <listitem>
      <para>
       Add a validator function for PL/Perl (Andrew)
      </para>
      <para>
       This allows syntax errors to be reported at definition time,
       rather than execution time.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow PL/Perl to return a Perl array when the function returns
       an array type (Andrew)
      </para>
      <para>
       This basically maps <productname>PostgreSQL</productname> arrays
       to Perl arrays.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow Perl nonfatal warnings to generate <command>NOTICE</>
       messages (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow Perl's <literal>strict</> mode to be enabled (Andrew)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title><application>psql</> Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add <command>\set ON_ERROR_ROLLBACK</> to allow statements in
       a transaction to error without affecting the rest of the
       transaction (Greg Sabino Mullane)
      </para>
      <para>
       This is basically implemented by wrapping every statement in a
       sub-transaction.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for <literal>\x</> hex strings in
       <application>psql</> variables (Bruce)
      </para>
      <para>
       Octal escapes were already supported.
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for <command>troff -ms</> output format (Roger
       Leigh)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow the history file location to be controlled by
       <envar>HISTFILE</> (Andreas Seltenreich)
      </para>
      <para>
       This allows configuration of per-database history storage.
      </para>
     </listitem>

     <listitem>
      <para>
       Prevent <command>\x</> (expanded mode) from affecting
       the output of <command>\d tablename</> (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <option>-L</> option to <application>psql</application> to
       log sessions (Lorne Sunley)
      </para>
      <para>
       This option was added because some operating systems do not have
       simple command-line activity logging functionality.
      </para>
     </listitem>

     <listitem>
      <para>
       Make <command>\d</> show the tablespaces of indexes (Qingqing
       Zhou)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <application>psql</application> help (<command>\h</>) to
       make a best guess on the proper help information (Greg Sabino
       Mullane)
      </para>
      <para>
       This allows the user to just add <command>\h</> to the front of
       the syntax error query and get help on the supported syntax.
       Previously any additional query text beyond the command name
       had to be removed to use <command>\h</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <command>\pset numericlocale</> to allow numbers to be
       output in a locale-aware format (Eugen Nedelcu)
      </para>
      <para>
       For example, using <literal>C</> locale <literal>100000</> would
       be output as <literal>100,000.0</> while a European locale might
       output this value as <literal>100.000,0</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Make startup banner show both server version number and
       <application>psql</>'s version number, when they are different (Bruce)
      </para>
      <para>
       Also, a warning will be shown if the server and <application>psql</>
       are from different major releases.
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title><application>pg_dump</> Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add <option>-n</> / <option>--schema</> switch to
       <application>pg_restore</> (Richard van den Berg)
      </para>
      <para>
       This allows just the objects in a specified schema to be restored.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <application>pg_dump</> to dump large objects even in
       text mode (Tom)
      </para>
      <para>
       With this change, large objects are now always dumped; the former
       <option>-b</> switch is a no-op.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <application>pg_dump</> to dump a consistent snapshot of
       large objects (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Dump comments for large objects (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <option>--encoding</> to <application>pg_dump</>
       (Magnus Hagander)
      </para>
      <para>
       This allows a database to be dumped in an encoding that is
       different from the server's encoding. This is valuable when
       transferring the dump to a machine with a different encoding.
      </para>
     </listitem>

     <listitem>
      <para>
       Rely on <structname>pg_pltemplate</> for procedural languages (Tom)
      </para>
      <para>
       If the call handler for a procedural language is in the
       <literal>pg_catalog</> schema, <application>pg_dump</> does not
       dump the handler.  Instead, it dumps the language using just
       <command>CREATE LANGUAGE <replaceable>name</></command>,
       relying on the <structname>pg_pltemplate</> catalog to provide
       the language's creation parameters at load time.
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title><application>libpq</application> Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add a <envar>PGPASSFILE</> environment variable to specify the
       password file's filename (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>lo_create()</>, that is similar to
       <function>lo_creat()</> but allows the OID of the large object
       to be specified (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <application>libpq</application> consistently return an error
       to the client application on <function>malloc()</function>
       failure (Neil)
      </para>
     </listitem>
    </itemizedlist>
   </sect3>


   <sect3>
    <title>Source Code Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Fix <application>pgxs</> to support building against a relocated
       installation
      </para>
     </listitem>

     <listitem>
      <para>
       Add spinlock support for the Itanium processor using Intel
       compiler (Vikram Kalsi)
      </para>
     </listitem>

     <listitem>
      <para>
       Add Kerberos 5 support for Windows (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Add Chinese FAQ (laser@pgsqldb.com)
      </para>
     </listitem>

     <listitem>
      <para>
       Rename Rendezvous to Bonjour to match OS/X feature renaming
       (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Add support for <literal>fsync_writethrough</literal> on
       Darwin (Chris Campbell)
      </para>
     </listitem>

     <listitem>
      <para>
       Streamline the passing of information within the server, the
       optimizer, and the lock system (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <application>pg_config</> to be compiled using MSVC (Andrew)
      </para>
      <para>
       This is required to build DBD::Pg using <application>MSVC</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove support for Kerberos V4 (Magnus)
      </para>
      <para>
       Kerberos 4 had security vulnerabilities and is no longer
       maintained.
      </para>
     </listitem>

     <listitem>
      <para>
       Code cleanups (Coverity static analysis performed by
       EnterpriseDB)
      </para>
     </listitem>

     <listitem>
      <para>
       Modify <filename>postgresql.conf</> to use documentation defaults
       <literal>on</>/<literal>off</> rather than
       <literal>true</>/<literal>false</> (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Enhance <application>pg_config</> to be able to report more
       build-time values (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <application>libpq</application> to be built thread-safe
       on Windows (Dave Page)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow IPv6 connections to be used on Windows (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Add Server Administration documentation about I/O subsystem
       reliability (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Move private declarations from <filename>gist.h</filename> to
       <filename>gist_private.h</filename> (Neil)
      </para>

      <para>
       In previous releases, <filename>gist.h</> contained both the
       public GiST API (intended for use by authors of GiST index
       implementations) as well as some private declarations used by
       the implementation of GiST itself. The latter have been moved
       to a separate file, <filename>gist_private.h</>. Most GiST
       index implementations should be unaffected.
      </para>
     </listitem>

     <listitem>
      <para>
       Overhaul GiST memory management (Neil)
      </para>

      <para>
       GiST methods are now always invoked in a short-lived memory
       context. Therefore, memory allocated via <function>palloc()</>
       will be reclaimed automatically, so GiST index implementations
       do not need to manually release allocated memory via
       <function>pfree()</>.
      </para>
     </listitem>
    </itemizedlist>
   </sect3>


   <sect3>
    <title>Contrib Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add <filename>/contrib/pg_buffercache</> contrib module (Mark
       Kirkwood)
      </para>
      <para>
       This displays the contents of the buffer cache, for debugging and
       performance tuning purposes.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <filename>/contrib/array</> because it is obsolete (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Clean up the <filename>/contrib/lo</> module (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Move <filename>/contrib/findoidjoins</> to
       <filename>/src/tools</> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Remove the <literal>&lt;&lt;</>, <literal>&gt;&gt;</>,
       <literal>&amp;&lt;</>, and <literal>&amp;&gt;</> operators from
       <filename>/contrib/cube</>
      </para>
      <para>
       These operators were not useful.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve <filename>/contrib/btree_gist</> (Janko Richter)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve <filename>/contrib/pgbench</> (Tomoaki Sato, Tatsuo)
      </para>
      <para>
       There is now a facility for testing with SQL command scripts given
       by the user, instead of only a hard-wired command sequence.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve <filename>/contrib/pgcrypto</> (Marko Kreen)
      </para>

      <itemizedlist>

       <listitem>
        <para>
         Implementation of OpenPGP symmetric-key and public-key encryption
        </para>
        <para>
         Both RSA and Elgamal public-key algorithms are supported.
        </para>
       </listitem>

       <listitem>
        <para>
         Stand alone build: include SHA256/384/512 hashes, Fortuna PRNG
        </para>
       </listitem>

       <listitem>
        <para>
         OpenSSL build: support 3DES, use internal AES with OpenSSL &lt; 0.9.7
        </para>
       </listitem>

       <listitem>
        <para>
         Take build parameters (OpenSSL, zlib) from <filename>configure</> result
        </para>
        <para>
         There is no need to edit the <filename>Makefile</> anymore.
        </para>
       </listitem>

       <listitem>
        <para>
         Remove support for <filename>libmhash</> and <filename>libmcrypt</>
        </para>
       </listitem>

      </itemizedlist>
     </listitem>

    </itemizedlist>
   </sect3>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-14">
  <title>Release 8.0.14</title>

  <note>
  <title>Release date</title>
  <simpara>2007-09-17</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.0.13.
  </para>

  <sect2>
   <title>Migration to Version 8.0.14</title>

   <para>
    A dump/restore is not required for those running 8.0.X.  However,
    if you are upgrading from a version earlier than 8.0.6, see the release
    notes for 8.0.6.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Prevent index corruption when a transaction inserts rows and
      then aborts close to the end of a concurrent <command>VACUUM</>
      on the same table (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Make <command>CREATE DOMAIN ... DEFAULT NULL</> work properly (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix excessive logging of <acronym>SSL</> error messages (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix logging so that log messages are never interleaved when using
      the syslogger process (Andrew)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix crash when <varname>log_min_error_statement</> logging runs out
      of memory (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix incorrect handling of some foreign-key corner cases (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Prevent <command>CLUSTER</> from failing
      due to attempting to process temporary tables of other sessions (Alvaro)
     </para>
    </listitem>

    <listitem>
     <para>
      Update the time zone database rules, particularly New Zealand's upcoming changes (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Windows socket improvements (Magnus)
     </para>
    </listitem>

    <listitem>
     <para>
      Suppress timezone name (<literal>%Z</>) in log timestamps on Windows
      because of possible encoding mismatches (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Require non-superusers who use <filename>/contrib/dblink</> to use only
      password authentication, as a security measure (Joe)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-13">
  <title>Release 8.0.13</title>

  <note>
  <title>Release date</title>
  <simpara>2007-04-23</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.0.12,
   including a security fix.
  </para>

  <sect2>
   <title>Migration to Version 8.0.13</title>

   <para>
    A dump/restore is not required for those running 8.0.X.  However,
    if you are upgrading from a version earlier than 8.0.6, see the release
    notes for 8.0.6.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
    <para>
     Support explicit placement of the temporary-table schema within
     <varname>search_path</>, and disable searching it for functions
     and operators (Tom)
    </para>
    <para>
     This is needed to allow a security-definer function to set a
     truly secure value of <varname>search_path</>.  Without it,
     an unprivileged SQL user can use temporary objects to execute code
     with the privileges of the security-definer function (CVE-2007-2138).
     See <command>CREATE FUNCTION</> for more information.
    </para>
    </listitem>

    <listitem>
    <para>
     <filename>/contrib/tsearch2</> crash fixes (Teodor)
    </para>
    </listitem>

    <listitem>
    <para>
     Fix potential-data-corruption bug in how <command>VACUUM FULL</> handles
     <command>UPDATE</> chains (Tom, Pavan Deolasee)
    </para>
    </listitem>

    <listitem>
    <para>
     Fix PANIC during enlargement of a hash index (bug introduced in 8.0.10)
     (Tom)
    </para>
    </listitem>

    <listitem>
    <para>
     Fix POSIX-style timezone specs to follow new USA DST rules (Tom)
    </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-12">
  <title>Release 8.0.12</title>

  <note>
  <title>Release date</title>
  <simpara>2007-02-07</simpara>
  </note>

  <para>
   This release contains one fix from 8.0.11.
  </para>

  <sect2>
   <title>Migration to Version 8.0.12</title>

   <para>
    A dump/restore is not required for those running 8.0.X.  However,
    if you are upgrading from a version earlier than 8.0.6, see the release
    notes for 8.0.6.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
    <para>
     Remove overly-restrictive check for type length in constraints and
     functional indexes(Tom)
    </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-11">
  <title>Release 8.0.11</title>

  <note>
  <title>Release date</title>
  <simpara>2007-02-05</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.0.10, including
   a security fix.
  </para>

  <sect2>
   <title>Migration to Version 8.0.11</title>

   <para>
    A dump/restore is not required for those running 8.0.X.  However,
    if you are upgrading from a version earlier than 8.0.6, see the release
    notes for 8.0.6.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
    <para>
     Remove security vulnerabilities that allowed connected users
     to read backend memory (Tom)
    </para>
    <para>
     The vulnerabilities involve suppressing the normal check that a SQL
     function returns the data type it's declared to, and changing the
     data type of a table column (CVE-2007-0555, CVE-2007-0556).  These
     errors can easily be exploited to cause a backend crash, and in
     principle might be used to read database content that the user
     should not be able to access.
    </para>
    </listitem>

    <listitem>
    <para>
     Fix rare bug wherein btree index page splits could fail
     due to choosing an infeasible split point (Heikki Linnakangas)
    </para>
    </listitem>

    <listitem>
    <para>
     Fix for rare Assert() crash triggered by <literal>UNION</> (Tom)
    </para>
    </listitem>

    <listitem>
    <para>
     Tighten security of multi-byte character processing for UTF8 sequences
     over three bytes long (Tom)
    </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-10">
  <title>Release 8.0.10</title>

  <note>
  <title>Release date</title>
  <simpara>2007-01-08</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.0.9.
  </para>

  <sect2>
   <title>Migration to Version 8.0.10</title>

   <para>
    A dump/restore is not required for those running 8.0.X.  However,
    if you are upgrading from a version earlier than 8.0.6, see the release
    notes for 8.0.6.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Improve handling of <function>getaddrinfo()</> on AIX (Tom)
     </para>

     <para>
      This fixes a problem with starting the statistics collector,
      among other things.
     </para>
    </listitem>

     <listitem>
      <para>
       Fix <quote>failed to re-find parent key</> errors in
       <command>VACUUM</> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix race condition for truncation of a large relation across a
       gigabyte boundary by <command>VACUUM</> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix bugs affecting multi-gigabyte hash indexes (Tom)
      </para>
     </listitem>

    <listitem>
     <para>
      Fix possible deadlock in Windows signal handling (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix error when constructing an <literal>ARRAY[]</> made up of multiple
      empty elements (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix ecpg memory leak during connection (Michael)
     </para>
    </listitem>

    <listitem>
     <para>
      <function>to_number()</> and <function>to_char(numeric)</>
      are now <literal>STABLE</>, not <literal>IMMUTABLE</>, for
      new <application>initdb</> installs (Tom)
     </para>

     <para>
      This is because <varname>lc_numeric</> can potentially
      change the output of these functions.
     </para>
    </listitem>

    <listitem>
     <para>
      Improve index usage of regular expressions that use parentheses (Tom)
     </para>

     <para>
      This improves <application>psql</> <literal>\d</> performance also.
     </para>
    </listitem>

    <listitem>
     <para>
      Update timezone database
     </para>

     <para>
      This affects Australian and Canadian daylight-savings rules in
      particular.
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-9">
  <title>Release 8.0.9</title>

  <note>
  <title>Release date</title>
  <simpara>2006-10-16</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.0.8.
  </para>

  <sect2>
   <title>Migration to Version 8.0.9</title>

   <para>
    A dump/restore is not required for those running 8.0.X.  However,
    if you are upgrading from a version earlier than 8.0.6, see the release
    notes for 8.0.6.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Fix crash when referencing <literal>NEW</> row
values in rule WHERE expressions (Tom)</para></listitem>
<listitem><para>Fix core dump when an untyped literal is taken as
ANYARRAY</para></listitem>
<listitem><para>Fix mishandling of AFTER triggers when query contains a SQL
function returning multiple rows (Tom)</para></listitem>
<listitem><para>Fix <command>ALTER TABLE ... TYPE</> to recheck
<literal>NOT NULL</> for <literal>USING</> clause (Tom)</para></listitem>
<listitem><para>Fix <function>string_to_array()</> to handle overlapping
 matches for the separator string</para>
<para>For example, <literal>string_to_array('123xx456xxx789', 'xx')</>.
</para></listitem>
<listitem><para>Fix corner cases in pattern matching for
 <application>psql</>'s <literal>\d</> commands</para></listitem>
<listitem><para>Fix index-corrupting bugs in /contrib/ltree
 (Teodor)</para></listitem>
<listitem><para>Numerous robustness fixes in <application>ecpg</> (Joachim
Wieland)</para></listitem>
<listitem><para>Fix backslash escaping in /contrib/dbmirror</para></listitem>
<listitem><para>Fix instability of statistics collection on Win32 (Tom, Andrew)</para></listitem>
<listitem><para>Fixes for <systemitem class="osname">AIX</> and
<productname>Intel</> compilers (Tom)</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-8">
  <title>Release 8.0.8</title>

  <note>
  <title>Release date</title>
  <simpara>2006-05-23</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.0.7,
   including patches for extremely serious security issues.
  </para>

  <sect2>
   <title>Migration to Version 8.0.8</title>

   <para>
    A dump/restore is not required for those running 8.0.X.  However,
    if you are upgrading from a version earlier than 8.0.6, see the release
    notes for 8.0.6.
   </para>

   <para>
    Full security against the SQL-injection attacks described in
    CVE-2006-2313 and CVE-2006-2314 might require changes in application
    code.  If you have applications that embed untrustworthy strings
    into SQL commands, you should examine them as soon as possible to
    ensure that they are using recommended escaping techniques.  In
    most cases, applications should be using subroutines provided by
    libraries or drivers (such as <application>libpq</>'s
    <function>PQescapeStringConn()</>) to perform string escaping,
    rather than relying on <foreignphrase>ad hoc</> code to do it.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Change the server to reject invalidly-encoded multibyte
characters in all cases (Tatsuo, Tom)</para>
<para>While <productname>PostgreSQL</> has been moving in this direction for
some time, the checks are now applied uniformly to all encodings and all
textual input, and are now always errors not merely warnings.  This change
defends against SQL-injection attacks of the type described in CVE-2006-2313.
</para></listitem>

<listitem><para>Reject unsafe uses of <literal>\'</> in string literals</para>
<para>As a server-side defense against SQL-injection attacks of the type
described in CVE-2006-2314, the server now only accepts <literal>''</> and not
<literal>\'</> as a representation of ASCII single quote in SQL string
literals.  By default, <literal>\'</> is rejected only when
<varname>client_encoding</> is set to a client-only encoding (SJIS, BIG5, GBK,
GB18030, or UHC), which is the scenario in which SQL injection is possible.
A new configuration parameter <varname>backslash_quote</> is available to
adjust this behavior when needed.  Note that full security against
CVE-2006-2314 might require client-side changes; the purpose of
<varname>backslash_quote</> is in part to make it obvious that insecure
clients are insecure.
</para></listitem>

<listitem><para>Modify <application>libpq</>'s string-escaping routines to be
aware of encoding considerations and
<varname>standard_conforming_strings</></para>
<para>This fixes <application>libpq</>-using applications for the security
issues described in CVE-2006-2313 and CVE-2006-2314, and also future-proofs
them against the planned changeover to SQL-standard string literal syntax.
Applications that use multiple <productname>PostgreSQL</> connections
concurrently should migrate to <function>PQescapeStringConn()</> and
<function>PQescapeByteaConn()</> to ensure that escaping is done correctly
for the settings in use in each database connection.  Applications that
do string escaping <quote>by hand</> should be modified to rely on library
routines instead.
</para></listitem>

<listitem><para>Fix some incorrect encoding conversion functions</para>
<para><function>win1251_to_iso</>, <function>alt_to_iso</>,
<function>euc_tw_to_big5</>, <function>euc_tw_to_mic</>,
<function>mic_to_euc_tw</> were all broken to varying
extents.
</para></listitem>

<listitem><para>Clean up stray remaining uses of <literal>\'</> in strings
(Bruce, Jan)</para></listitem>

<listitem><para>Fix bug that sometimes caused OR'd index scans to
miss rows they should have returned</para></listitem>

<listitem><para>Fix WAL replay for case where a btree index has been
truncated</para></listitem>

<listitem><para>Fix <literal>SIMILAR TO</> for patterns involving
<literal>|</> (Tom)</para></listitem>

<listitem><para>Fix <command>SELECT INTO</> and <command>CREATE TABLE AS</> to
create tables in the default tablespace, not the base directory (Kris
Jurka)</para></listitem>

<listitem><para>Fix server to use custom DH SSL parameters correctly (Michael
Fuhr)</para></listitem>

<listitem><para>Fix for Bonjour on Intel Macs (Ashley Clark)</para></listitem>

<listitem><para>Fix various minor memory leaks</para></listitem>

<listitem><para>Fix problem with password prompting on some Win32 systems
(Robert Kinberg)</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-7">
  <title>Release 8.0.7</title>

  <note>
  <title>Release date</title>
  <simpara>2006-02-14</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.0.6.
  </para>

  <sect2>
   <title>Migration to Version 8.0.7</title>

   <para>
    A dump/restore is not required for those running 8.0.X.  However,
    if you are upgrading from a version earlier than 8.0.6, see the release
    notes for 8.0.6.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>

<listitem><para>Fix potential crash in <command>SET
SESSION AUTHORIZATION</> (CVE-2006-0553)</para>
<para>An unprivileged user could crash the server process, resulting in
momentary denial of service to other users, if the server has been compiled
with Asserts enabled (which is not the default).
Thanks to Akio Ishida for reporting this problem.
</para></listitem>

<listitem><para>Fix bug with row visibility logic in self-inserted
rows (Tom)</para>
<para>Under rare circumstances a row inserted by the current command
could be seen as already valid, when it should not be.  Repairs bug
created in 8.0.4, 7.4.9, and 7.3.11 releases.
</para></listitem>

<listitem><para>Fix race condition that could lead to <quote>file already
exists</> errors during pg_clog and pg_subtrans file creation
(Tom)</para></listitem>

<listitem><para>Fix cases that could lead to crashes if a cache-invalidation
message arrives at just the wrong time (Tom)</para></listitem>

<listitem><para>Properly check <literal>DOMAIN</> constraints for
<literal>UNKNOWN</> parameters in prepared statements
(Neil)</para></listitem>

<listitem><para>Ensure <command>ALTER COLUMN TYPE</> will process
<literal>FOREIGN KEY</>, <literal>UNIQUE</>, and <literal>PRIMARY KEY</>
constraints in the proper order (Nakano Yoshihisa)</para></listitem>

<listitem><para>Fixes to allow restoring dumps that have cross-schema
references to custom operators or operator classes (Tom)</para></listitem>

<listitem><para>Allow <application>pg_restore</> to continue properly after a
<command>COPY</> failure; formerly it tried to treat the remaining
<command>COPY</> data as SQL commands (Stephen Frost)</para></listitem>

<listitem><para>Fix <application>pg_ctl</> <literal>unregister</> crash
when the  data directory is not specified (Magnus)</para></listitem>

<listitem><para>Fix <application>ecpg</> crash on AMD64 and PPC
(Neil)</para></listitem>

<listitem><para>Recover properly if error occurs during argument passing
in <application>PL/python</> (Neil)</para></listitem>

<listitem><para>Fix <application>PL/perl</>'s handling of locales on
Win32 to match the backend (Andrew)</para></listitem>

<listitem><para>Fix crash when <literal>log_min_messages</> is set to
<literal>DEBUG3</> or above in <filename>postgresql.conf</> on Win32
(Bruce)</para></listitem>

<listitem><para>Fix <application>pgxs</> <literal>-L</> library path
specification for Win32, Cygwin, OS X, AIX (Bruce)</para></listitem>

<listitem><para>Check that SID is enabled while checking for Win32 admin
privileges (Magnus)</para></listitem>

<listitem><para>Properly reject out-of-range date inputs (Kris
Jurka)</para></listitem>

<listitem><para>Portability fix for testing presence of <function>finite</>
and <function>isinf</> during configure (Tom)</para></listitem>

</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-6">
  <title>Release 8.0.6</title>

  <note>
  <title>Release date</title>
  <simpara>2006-01-09</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.0.5.
  </para>

  <sect2>
   <title>Migration to Version 8.0.6</title>

   <para>
    A dump/restore is not required for those running 8.0.X.  However,
    if you are upgrading from a version earlier than 8.0.3, see the release
    notes for 8.0.3.
    Also, you might need to <command>REINDEX</> indexes on textual
    columns after updating, if you are affected by the locale or
    <application>plperl</> issues described below.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>

<listitem><para>Fix Windows code so that postmaster will continue rather
than exit if there is no more room in ShmemBackendArray (Magnus)</para>
<para>The previous behavior could lead to a denial-of-service situation if too
many connection requests arrive close together.  This applies
<emphasis>only</> to the Windows port.</para></listitem>

<listitem><para>Fix bug introduced in 8.0 that could allow ReadBuffer
to return an already-used page as new, potentially causing loss of
recently-committed data (Tom)</para></listitem>

<listitem><para>Fix for protocol-level Describe messages issued
outside a transaction or in a failed transaction (Tom)</para></listitem>

<listitem><para>Fix character string comparison for locales that consider
different character combinations as equal, such as Hungarian (Tom)</para>
<para>This might require <command>REINDEX</> to fix existing indexes on
textual columns.</para></listitem>

<listitem><para>Set locale environment variables during postmaster startup
to ensure that <application>plperl</> won't change the locale later</para>
<para>This fixes a problem that occurred if the <application>postmaster</> was
started with environment variables specifying a different locale than what
<application>initdb</> had been told.  Under these conditions, any use of
<application>plperl</> was likely to lead to corrupt indexes.  You might need
<command>REINDEX</> to fix existing indexes on
textual columns if this has happened to you.</para></listitem>

<listitem><para>Allow more flexible relocation of installation
directories (Tom)</para>
<para>Previous releases supported relocation only if all installation
directory paths were the same except for the last component.</para></listitem>

<listitem><para>Fix longstanding bug in strpos() and regular expression
handling in certain rarely used Asian multi-byte character sets (Tatsuo)
</para></listitem>

<listitem><para>Various fixes for functions returning <literal>RECORD</>s
(Tom) </para></listitem>

<listitem><para>Fix bug in <filename>/contrib/pgcrypto</> gen_salt,
which caused it not to use all available salt space for MD5 and
XDES algorithms (Marko Kreen, Solar Designer)</para>
<para>Salts for Blowfish and standard DES are unaffected.</para></listitem>

<listitem><para>Fix <filename>/contrib/dblink</> to throw an error,
rather than crashing, when the number of columns specified is different from
what's actually returned by the query (Joe)</para></listitem>

</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-5">
  <title>Release 8.0.5</title>

  <note>
  <title>Release date</title>
  <simpara>2005-12-12</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.0.4.
  </para>

  <sect2>
   <title>Migration to Version 8.0.5</title>

   <para>
    A dump/restore is not required for those running 8.0.X.  However,
    if you are upgrading from a version earlier than 8.0.3, see the release
    notes for 8.0.3.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>

<listitem><para>Fix race condition in transaction log management</para>
<para>There was a narrow window in which an I/O operation could be initiated
for the wrong page, leading to an Assert failure or data
corruption.</para>
</listitem>

<listitem><para>Fix bgwriter problems after recovering from errors
(Tom)</para>
<para>
The background writer was found to leak buffer pins after write errors.
While not fatal in itself, this might lead to mysterious blockages of
later VACUUM commands.
</para>
</listitem>

<listitem><para>Prevent failure if client sends Bind protocol message
when current transaction is already aborted</para></listitem>

<listitem><para><filename>/contrib/ltree</> fixes (Teodor)</para></listitem>

<listitem><para>AIX and HPUX compile fixes (Tom)</para></listitem>

<listitem><para>Retry file reads and writes after Windows
NO_SYSTEM_RESOURCES error (Qingqing Zhou)</para></listitem>

<listitem><para>Fix intermittent failure when <varname>log_line_prefix</>
includes <literal>%i</></para></listitem>

<listitem><para>Fix <application>psql</> performance issue with long scripts
on Windows (Merlin Moncure)</para></listitem>

<listitem><para>Fix missing updates of <filename>pg_group</> flat
file</para></listitem>

<listitem><para>Fix longstanding planning error for outer joins</para>
<para>This bug sometimes caused a bogus error <quote>RIGHT JOIN is
only supported with merge-joinable join conditions</>.</para></listitem>

<listitem><para>Postpone timezone initialization until after
<filename>postmaster.pid</> is created</para>
<para>This avoids confusing startup scripts that expect the pid file to appear
quickly.</para></listitem>

<listitem><para>Prevent core dump in <application>pg_autovacuum</> when a
table has been dropped</para></listitem>

<listitem><para>Fix problems with whole-row references (<literal>foo.*</>)
to subquery results</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-4">
  <title>Release 8.0.4</title>

  <note>
  <title>Release date</title>
  <simpara>2005-10-04</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.0.3.
  </para>

  <sect2>
   <title>Migration to Version 8.0.4</title>

   <para>
    A dump/restore is not required for those running 8.0.X.  However,
    if you are upgrading from a version earlier than 8.0.3, see the release
    notes for 8.0.3.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Fix error that allowed <command>VACUUM</> to remove
<literal>ctid</> chains too soon, and add more checking in code that follows
<literal>ctid</> links</para>
<para>This fixes a long-standing problem that could cause crashes in very rare
circumstances.</para></listitem>
<listitem><para>Fix <type>CHAR()</> to properly pad spaces to the specified
length when using a multiple-byte character set (Yoshiyuki Asaba)</para>
<para>In prior releases, the padding of <type>CHAR()</> was incorrect
because it only padded to the specified number of bytes without
considering how many characters were stored.</para></listitem>
<listitem><para>Force a checkpoint before committing <command>CREATE
DATABASE</></para>
<para>This should fix recent reports of <quote>index is not a btree</>
failures when a crash occurs shortly after <command>CREATE
DATABASE</>.</para></listitem>
<listitem><para>Fix the sense of the test for read-only transaction
in <command>COPY</></para>
<para>The code formerly prohibited <command>COPY TO</>, where it should
prohibit <command>COPY FROM</>.
</para></listitem>
<listitem><para>Handle consecutive embedded newlines in <command>COPY</>
CSV-mode input</para></listitem>
<listitem><para>Fix <function>date_trunc(week)</> for dates near year
end</para></listitem>
<listitem><para>Fix planning problem with outer-join ON clauses that reference
only the inner-side relation</para></listitem>
<listitem><para>Further fixes for <literal>x FULL JOIN y ON true</> corner
cases</para></listitem>
<listitem><para>Fix overenthusiastic optimization of <literal>x IN (SELECT
DISTINCT ...)</> and related cases</para></listitem>
<listitem><para>Fix mis-planning of queries with small <literal>LIMIT</>
values due to poorly thought out <quote>fuzzy</> cost
comparison</para></listitem>
<listitem><para>Make <function>array_in</> and <function>array_recv</> more
paranoid about validating their OID parameter</para></listitem>
<listitem><para>Fix missing rows in queries like <literal>UPDATE a=... WHERE
a...</> with GiST index on column <literal>a</></para></listitem>
<listitem><para>Improve robustness of datetime parsing</para></listitem>
<listitem><para>Improve checking for partially-written WAL
pages</para></listitem>
<listitem><para>Improve robustness of signal handling when SSL is
enabled</para></listitem>
<listitem><para>Improve MIPS and M68K spinlock code</para></listitem>
<listitem><para>Don't try to open more than <literal>max_files_per_process</>
files during postmaster startup</para></listitem>
<listitem><para>Various memory leakage fixes</para></listitem>
<listitem><para>Various portability improvements</para></listitem>
<listitem><para>Update timezone data files</para></listitem>
<listitem><para>Improve handling of DLL load failures on Windows</para></listitem>
<listitem><para>Improve random-number generation on Windows</para></listitem>
<listitem><para>Make <literal>psql -f filename</> return a nonzero exit code
when opening the file fails</para></listitem>
<listitem><para>Change <application>pg_dump</> to handle inherited check
constraints more reliably</para></listitem>
<listitem><para>Fix password prompting in <application>pg_restore</> on
Windows</para></listitem>
<listitem><para>Fix PL/PgSQL to handle <literal>var := var</> correctly when
the variable is of pass-by-reference type</para></listitem>
<listitem><para>Fix PL/Perl <literal>%_SHARED</> so it's actually
shared</para></listitem>
<listitem><para>Fix <filename>contrib/pg_autovacuum</> to allow sleep
intervals over 2000 sec</para></listitem>
<listitem><para>Update <filename>contrib/tsearch2</> to use current Snowball
code</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-3">
  <title>Release 8.0.3</title>

  <note>
  <title>Release date</title>
  <simpara>2005-05-09</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.0.2, including several
   security-related issues.
  </para>

  <sect2>
   <title>Migration to Version 8.0.3</title>

   <para>
    A dump/restore is not required for those running 8.0.X.  However,
    it is one possible way of handling two significant security problems
    that have been found in the initial contents of 8.0.X system
    catalogs.  A dump/initdb/reload sequence using 8.0.3's initdb will
    automatically correct these problems.
   </para>

   <para>
    The larger security problem is that the built-in character set encoding
    conversion functions can be invoked from SQL commands by unprivileged
    users, but the functions were not designed for such use and are not
    secure against malicious choices of arguments.  The fix involves changing
    the declared parameter list of these functions so that they can no longer
    be invoked from SQL commands.  (This does not affect their normal use
    by the encoding conversion machinery.)
   </para>

   <para>
    The lesser problem is that the <filename>contrib/tsearch2</> module
    creates several functions that are improperly declared to return
    <type>internal</> when they do not accept <type>internal</> arguments.
    This breaks type safety for all functions using <type>internal</>
    arguments.
   </para>

   <para>
    It is strongly recommended that all installations repair these errors,
    either by initdb or by following the manual repair procedure given
    below.  The errors at least allow unprivileged database users to crash
    their server process, and might allow unprivileged users to gain the
    privileges of a database superuser.
   </para>

   <para>
    If you wish not to do an initdb, perform the same manual repair
    procedures shown in the <link linkend="release-7-4-8">7.4.8 release
    notes</link>.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Change encoding function signature to prevent
misuse</para></listitem>
<listitem><para>Change <filename>contrib/tsearch2</> to avoid unsafe use of
<type>INTERNAL</> function results</para></listitem>
<listitem><para>Guard against incorrect second parameter to
<function>record_out</></para></listitem>
<listitem><para>Repair ancient race condition that allowed a transaction to be
seen as committed for some purposes (eg SELECT FOR UPDATE) slightly sooner
than for other purposes</para>
<para>This is an extremely serious bug since it could lead to apparent
data inconsistencies being briefly visible to applications.</para></listitem>
<listitem><para>Repair race condition between relation extension and
VACUUM</para>
<para>This could theoretically have caused loss of a page's worth of
freshly-inserted data, although the scenario seems of very low probability.
There are no known cases of it having caused more than an Assert failure.
</para></listitem>
<listitem><para>Fix comparisons of <type>TIME WITH TIME ZONE</> values</para>
<para>
The comparison code was wrong in the case where the
<literal>--enable-integer-datetimes</> configuration switch had been used.
NOTE: if you have an index on a <type>TIME WITH TIME ZONE</> column,
it will need to be <command>REINDEX</>ed after installing this update, because
the fix corrects the sort order of column values.
</para></listitem>
<listitem><para>Fix <function>EXTRACT(EPOCH)</> for
<type>TIME WITH TIME ZONE</> values</para></listitem>
<listitem><para>Fix mis-display of negative fractional seconds in
<type>INTERVAL</> values</para>
<para>
This error only occurred when the
<literal>--enable-integer-datetimes</> configuration switch had been used.
</para></listitem>
<listitem><para>Fix pg_dump to dump trigger names containing <literal>%</>
correctly (Neil)</para></listitem>
<listitem><para>Still more 64-bit fixes for
<filename>contrib/intagg</></para></listitem>
<listitem><para>Prevent incorrect optimization of functions returning
<type>RECORD</></para></listitem>
<listitem><para>Prevent crash on <literal>COALESCE(NULL,NULL)</></para></listitem>
<listitem><para>Fix Borland makefile for libpq</para></listitem>
<listitem><para>Fix <filename>contrib/btree_gist</> for <type>timetz</> type
(Teodor)</para></listitem>
<listitem><para>Make <command>pg_ctl</> check the PID found in
<filename>postmaster.pid</> to see if it is still a live
process</para></listitem>
<listitem><para>Fix <command>pg_dump</>/<command>pg_restore</> problems caused
by addition of dump timestamps</para></listitem>
<listitem><para>Fix interaction between materializing holdable cursors and
firing deferred triggers during transaction commit</para></listitem>
<listitem><para>Fix memory leak in SQL functions returning pass-by-reference
data types</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-2">
  <title>Release 8.0.2</title>

  <note>
  <title>Release date</title>
  <simpara>2005-04-07</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.0.1.
  </para>

  <sect2>
   <title>Migration to Version 8.0.2</title>

   <para>
    A dump/restore is not required for those running 8.0.*.
    This release updates the major version number of the
    <productname>PostgreSQL</productname> libraries, so it might be
    necessary to re-link some user applications if they cannot
    find the properly-numbered shared library.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Increment the major version number of all interface
libraries (Bruce)</para>
<para>
This should have been done in 8.0.0.  It is required so 7.4.X versions
of PostgreSQL client applications, like <application>psql</>,
can be used on the same machine as 8.0.X applications.  This might require
re-linking user applications that use these libraries.
</para></listitem>
<listitem><para>Add Windows-only <varname>wal_sync_method</> setting of
<option>fsync_writethrough</> (Magnus, Bruce)</para>
<para>
This setting causes <productname>PostgreSQL</productname> to write through
any disk-drive write cache when writing to WAL.
This behavior was formerly called <option>fsync</>, but was
renamed because it acts quite differently from <option>fsync</> on other
platforms.
</para>
</listitem>
<listitem><para>Enable the <varname>wal_sync_method</> setting of
<option>open_datasync</> on Windows, and make it the default for that
 platform (Magnus, Bruce)</para>
<para>
Because the default is no longer <option>fsync_writethrough</>,
data loss is possible during a power failure if the disk drive has
write caching enabled. To turn off the write cache on Windows,
from the <application>Device Manager</>, choose the drive properties,
then <literal>Policies</>.
</para>
</listitem>
<listitem><para>New cache management algorithm <acronym>2Q</> replaces
<acronym>ARC</> (Tom)</para>
<para>
This was done to avoid a pending US patent on <acronym>ARC</>.  The
<acronym>2Q</> code might be a few percentage points slower than
<acronym>ARC</> for some work loads.  A better cache management algorithm
will appear in 8.1.
</para></listitem>
<listitem><para>Planner adjustments to improve behavior on freshly-created
tables (Tom)</para></listitem>
<listitem><para>Allow plpgsql to assign to an element of an array that is
initially <literal>NULL</> (Tom)</para>
<para>
Formerly the array would remain <literal>NULL</>, but now it becomes a
single-element array.  The main SQL engine was changed to handle
<command>UPDATE</> of a null array value this way in 8.0, but the similar
case in plpgsql was overlooked.
</para>
</listitem>
<listitem><para>Convert <literal>\r\n</> and <literal>\r</> to <literal>\n</>
in plpython function bodies (Michael Fuhr)</para>
<para>
 This prevents syntax errors when plpython code is written on a Windows or
 Mac client.
</para>
</listitem>
<listitem><para>Allow SPI cursors to handle utility commands that return rows,
such as <command>EXPLAIN</> (Tom)</para></listitem>
<listitem><para>Fix <command>CLUSTER</> failure after <command>ALTER TABLE
SET WITHOUT OIDS</> (Tom)</para></listitem>
<listitem><para>Reduce memory usage of <command>ALTER TABLE ADD COLUMN</>
(Neil)</para></listitem>
<listitem><para>Fix <command>ALTER LANGUAGE RENAME</> (Tom)</para></listitem>
<listitem><para>Document the Windows-only <literal>register</> and
<literal>unregister</> options of <application>pg_ctl</> (Magnus)</para></listitem>
<listitem><para>Ensure operations done during backend shutdown are counted by
statistics collector</para>
<para>
This is expected to resolve reports of <application>pg_autovacuum</>
not vacuuming the system catalogs often enough &mdash; it was not being
told about catalog deletions caused by temporary table removal during
backend exit.
</para></listitem>
<listitem><para>Change the Windows default for configuration parameter
<varname>log_destination</> to <option>eventlog</> (Magnus)</para>
<para>
By default, a server running on Windows will now send log output to the
Windows event logger rather than standard error.
</para></listitem>
<listitem><para>Make Kerberos authentication work on Windows (Magnus)</para></listitem>
<listitem><para>Allow <command>ALTER DATABASE RENAME</> by superusers
who aren't flagged as having CREATEDB privilege (Tom)</para></listitem>
<listitem><para>Modify WAL log entries for <command>CREATE</> and
<command>DROP DATABASE</> to not specify absolute paths (Tom)</para>
<para>This allows point-in-time recovery on a different machine with possibly
different database location.  Note that <command>CREATE TABLESPACE</> still
poses a hazard in such situations.
</para></listitem>
<listitem><para>Fix crash from a backend exiting with an open transaction
that created a table and opened a cursor on it (Tom)</para></listitem>
<listitem><para>Fix <function>array_map()</> so it can call PL functions
(Tom)</para></listitem>
<listitem><para>Several <filename>contrib/tsearch2</> and
<filename>contrib/btree_gist</> fixes (Teodor)
</para></listitem>
<listitem><para>Fix crash of some <filename>contrib/pgcrypto</>
functions on some platforms (Marko Kreen)</para></listitem>
<listitem><para>Fix <filename>contrib/intagg</> for 64-bit platforms
(Tom)</para></listitem>
<listitem><para>Fix ecpg bugs in parsing of <command>CREATE</> statement
(Michael)</para></listitem>
<listitem><para>Work around gcc bug on powerpc and amd64 causing problems in
ecpg (Christof Petig)</para></listitem>
<listitem><para>Do not use locale-aware versions of <function>upper()</>,
<function>lower()</>, and <function>initcap()</> when the locale is
<literal>C</> (Bruce)</para>
<para>
 This allows these functions to work on platforms that generate errors
 for non-7-bit data when the locale is <literal>C</>.
</para></listitem>
<listitem><para>Fix <function>quote_ident()</> to quote names that match keywords (Tom)</para></listitem>
<listitem><para>Fix <function>to_date()</> to behave reasonably when
<literal>CC</> and <literal>YY</> fields are both used (Karel)</para></listitem>
<listitem><para>Prevent <function>to_char(interval)</> from failing
when given a zero-month interval (Tom)</para></listitem>
<listitem><para>Fix wrong week returned by <function>date_trunc('week')</>
(Bruce)</para>
<para>
<function>date_trunc('week')</>
returned the wrong year for the first few days of January in some years.
</para></listitem>
<listitem><para>Use the correct default mask length for class <literal>D</>
addresses in <type>INET</> data types (Tom)</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0-1">
  <title>Release 8.0.1</title>

  <note>
  <title>Release date</title>
  <simpara>2005-01-31</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.0.0, including several
   security-related issues.
  </para>

  <sect2>
   <title>Migration to Version 8.0.1</title>

   <para>
    A dump/restore is not required for those running 8.0.0.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Disallow <command>LOAD</> to non-superusers</para>
<para>
On platforms that will automatically execute initialization functions of a
shared library (this includes at least Windows and ELF-based Unixen),
<command>LOAD</> can be used to make the server execute arbitrary code.
Thanks to NGS Software for reporting this.</para></listitem>
<listitem><para>Check that creator of an aggregate function has the right to
execute the specified transition functions</para>
<para>
This oversight made it possible to bypass denial of EXECUTE
permission on a function.</para></listitem>
<listitem><para>Fix security and 64-bit issues in
contrib/intagg</para></listitem>
<listitem><para>Add needed STRICT marking to some contrib functions (Kris
Jurka)</para></listitem>
<listitem><para>Avoid buffer overrun when plpgsql cursor declaration has too
many parameters (Neil)</para></listitem>
<listitem><para>Make <command>ALTER TABLE ADD COLUMN</> enforce domain
constraints in all cases</para></listitem>
<listitem><para>Fix planning error for FULL and RIGHT outer joins</para>
<para>
The result of the join was mistakenly supposed to be sorted the same as the
left input.  This could not only deliver mis-sorted output to the user, but
in case of nested merge joins could give outright wrong answers.
</para></listitem>
<listitem><para>Improve planning of grouped aggregate queries</para></listitem>
<listitem><para><command>ROLLBACK TO <replaceable>savepoint</></command>
closes cursors created since the savepoint</para></listitem>
<listitem><para>Fix inadequate backend stack size on Windows</para></listitem>
<listitem><para>Avoid SHGetSpecialFolderPath() on Windows
(Magnus)</para></listitem>
<listitem><para>Fix some problems in running pg_autovacuum as a Windows
service (Dave Page)</para></listitem>
<listitem><para>Multiple minor bug fixes in
pg_dump/pg_restore</para></listitem>
<listitem><para>Fix ecpg segfault with named structs used in
typedefs (Michael)</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-0">
  <title>Release 8.0</title>

  <note>
   <title>Release date</title>
   <simpara>2005-01-19</simpara>
  </note>

  <sect2>
   <title>Overview</title>

   <para>
    Major changes in this release:
   </para>

   <variablelist>
    <varlistentry>
     <term>
      Microsoft Windows Native Server
     </term>

     <listitem>
      <para>
       This is the first <productname>PostgreSQL</productname> release
       to run natively on <trademark class="registered">Microsoft Windows</> as
       a server. It can run as a <productname>Windows</> service. This
       release supports NT-based Windows releases like
       <productname>Windows 2000 SP4</>, <productname>Windows XP</>, and
       <productname>Windows 2003</>. Older releases like
       <productname>Windows 95</>, <productname>Windows 98</>, and
       <productname>Windows ME</> are not supported because these operating
       systems do not have the infrastructure to support
       <productname>PostgreSQL</productname>. A separate installer
       project has been created to ease installation on
       <productname>Windows</> &mdash; see <ulink
       url="http://www.postgresql.org/ftp/win32/"></ulink>.
      </para>

      <para>
       Although tested throughout our release cycle, the Windows port
       does not have the benefit of years of use in production
       environments that <productname>PostgreSQL</productname> has on
       Unix platforms.  Therefore it should be treated with the same
       level of caution as you would a new product.
      </para>

      <para>
       Previous releases required the Unix emulation toolkit
       <productname>Cygwin</> in order to run the server on Windows
       operating systems.  <productname>PostgreSQL</productname> has
       supported native clients on Windows for many years.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Savepoints
     </term>

     <listitem>
      <para>
       Savepoints allow specific parts of a transaction to be aborted
       without affecting the remainder of the transaction. Prior
       releases had no such capability; there was no way to recover
       from a statement failure within a transaction except by
       aborting the whole transaction. This feature is valuable for
       application writers who require error recovery within a
       complex transaction.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Point-In-Time Recovery
     </term>

     <listitem>
      <para>
       In previous releases there was no way to recover from disk
       drive failure except to restore from a previous backup or use
       a standby replication server.  Point-in-time recovery allows
       continuous backup of the server.  You can recover either to
       the point of failure or to some transaction in the past.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Tablespaces
     </term>

     <listitem>
      <para>
       Tablespaces allow administrators to select different file systems
       for storage of individual tables, indexes, and databases.
       This improves performance and control over disk space
       usage. Prior releases used <application>initlocation</> and
       manual symlink management for such tasks.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Improved Buffer Management, <command>CHECKPOINT</command>,
      <command>VACUUM</command>
     </term>

     <listitem>
      <para>
       This release has a more intelligent buffer replacement strategy,
       which will make better use of available shared buffers and
       improve performance. The performance impact of vacuum and
       checkpoints is also lessened.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Change Column Types
     </term>

     <listitem>
      <para>
       A column's data type can now be changed with <command>ALTER
       TABLE</command>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      New Perl Server-Side Language
     </term>

     <listitem>
      <para>
       A new version of the <application>plperl</> server-side language now
       supports a persistent shared storage area, triggers, returning records
       and arrays of records, and SPI calls to access the database.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
       Comma-separated-value (CSV) support in <command>COPY</command>
     </term>

     <listitem>
      <para>
       <command>COPY</command> can now read and write
       comma-separated-value files. It has the flexibility to
       interpret nonstandard quoting and separation characters too.
      </para>
     </listitem>
    </varlistentry>

   </variablelist>
  </sect2>

  <sect2>
   <title>Migration to Version 8.0</title>

   <para>
    A dump/restore using <application>pg_dump</application> is
    required for those wishing to migrate data from any previous
    release.
   </para>

   <para>
    Observe the following incompatibilities:
   </para>

   <itemizedlist>

    <listitem>
     <para>
      In <option>READ COMMITTED</> serialization mode, volatile functions
      now see the results of concurrent transactions committed up to the
      beginning of each statement within the function, rather than up to the
      beginning of the interactive command that called the function.
     </para>
    </listitem>

    <listitem>
     <para>
      Functions declared <option>STABLE</> or <option>IMMUTABLE</> always
      use the snapshot of the calling query, and therefore do not see the
      effects of actions taken after the calling query starts, whether in
      their own transaction or other transactions.  Such a function must be
      read-only, too, meaning that it cannot use any SQL commands other than
      <command>SELECT</>.
     </para>
    </listitem>

    <listitem>
     <para>
      Nondeferred <option>AFTER</> triggers are now fired immediately
      after completion of the triggering query, rather than upon
      finishing the current interactive command. This makes a
      difference when the triggering query occurred within a function:
      the trigger is invoked before the function proceeds to its next
      operation.
     </para>
    </listitem>

    <listitem>
     <para>
      Server configuration parameters <varname>virtual_host</> and
      <varname>tcpip_socket</> have been replaced with a more general
      parameter <varname>listen_addresses</>. Also, the server now listens on
      <literal>localhost</> by default, which eliminates the need for the
      <literal>-i</> postmaster switch in many scenarios.
     </para>
    </listitem>

    <listitem>
     <para>
      Server configuration parameters <varname>SortMem</> and
      <varname>VacuumMem</> have been renamed to <varname>work_mem</>
      and <varname>maintenance_work_mem</> to better reflect their
      use. The original names are still supported in
      <command>SET</command> and <command>SHOW</command>.
     </para>
    </listitem>

    <listitem>
     <para>
      Server configuration parameters <varname>log_pid</>,
      <varname>log_timestamp</>, and <varname>log_source_port</> have been
      replaced with a more general parameter <varname>log_line_prefix</>.
     </para>
    </listitem>

    <listitem>
     <para>
      Server configuration parameter <varname>syslog</> has been
      replaced with a more logical <varname>log_destination</> variable to
      control the log output destination.
     </para>
    </listitem>

    <listitem>
     <para>
      Server configuration parameter <varname>log_statement</> has been
      changed so it can selectively log just database modification or
      data definition statements.  Server configuration parameter
      <varname>log_duration</> now prints only when <varname>log_statement</>
      prints the query.
     </para>
    </listitem>

    <listitem>
     <para>
      Server configuration parameter <varname>max_expr_depth</> parameter has
      been replaced with <varname>max_stack_depth</> which measures the
      physical stack size rather than the expression nesting depth. This
      helps prevent session termination due to stack overflow caused by
      recursive functions.
     </para>
    </listitem>

    <listitem>
     <para>
      The <function>length()</> function no longer counts trailing spaces in
      <type>CHAR(n)</> values.
     </para>
    </listitem>

   <listitem>
    <para>
     Casting an integer to <type>BIT(N)</> selects the rightmost N bits of the
     integer, not the leftmost N bits as before.
    </para>
   </listitem>

   <listitem>
    <para>
     Updating an element or slice of a NULL array value now produces
     a nonnull array result, namely an array containing
     just the assigned-to positions.
    </para>
   </listitem>

    <listitem>
     <para>
      Syntax checking of array input values has been tightened up
      considerably. Junk that was previously allowed in odd places with
      odd results now causes an error. Empty-string element values
      must now be written as <literal>""</>, rather than writing nothing.
      Also changed behavior with respect to whitespace surrounding
      array elements: trailing whitespace is now ignored, for symmetry
      with leading whitespace (which has always been ignored).
     </para>
    </listitem>

    <listitem>
     <para>
      Overflow in integer arithmetic operations is now detected and
      reported as an error.
     </para>
    </listitem>

    <listitem>
     <para>
      The arithmetic operators associated with the single-byte
      <type>"char"</> data type have been removed.
     </para>
    </listitem>

    <listitem>
     <para>
      The <function>extract()</> function (also called
      <function>date_part</>) now returns the proper year for BC dates.
      It previously returned one less than the correct year. The
      function now also returns the proper values for millennium and
      century.
     </para>
    </listitem>

   <listitem>
    <para>
     <type>CIDR</> values now must have their nonmasked bits be zero.
     For example, we no longer allow
     <literal>204.248.199.1/31</literal> as a <type>CIDR</> value. Such
     values should never have been accepted by
     <productname>PostgreSQL</productname> and will now be rejected.
    </para>
   </listitem>

    <listitem>
     <para>
      <command>EXECUTE</command> now returns a completion tag that
      matches the executed statement.
     </para>
    </listitem>

    <listitem>
     <para>
      <application>psql</>'s <command>\copy</> command now reads or
      writes to the query's <literal>stdin/stdout</>, rather than
      <application>psql</>'s <literal>stdin/stdout</>. The previous
      behavior can be accessed via new
      <option>pstdin</>/<option>pstdout</> parameters.
     </para>
    </listitem>

    <listitem>
     <para>
     The JDBC client interface has been removed from the core
     distribution, and is now hosted at <ulink url=
     "http://jdbc.postgresql.org"></ulink>.
     </para>
    </listitem>

    <listitem>
     <para>
     The Tcl client interface has also been removed. There are several
     Tcl interfaces now hosted at <ulink url=
     "http://gborg.postgresql.org"></ulink>.
     </para>
    </listitem>

    <listitem>
     <para>
      The server now uses its own time zone database, rather than the
      one supplied by the operating system. This will provide consistent
      behavior across all platforms.  In most cases, there should be
      little noticeable difference in time zone behavior, except that
      the time zone names used by <command>SET</>/<command>SHOW</>
      <varname>TimeZone</> might be different from what your platform provides.
     </para>
    </listitem>

    <listitem>
     <para>
      <application>Configure</>'s threading option no longer requires
      users to run tests or edit configuration files; threading options
      are now detected automatically.
     </para>
    </listitem>

    <listitem>
     <para>
      Now that tablespaces have been implemented,
      <application>initlocation</> has been removed.
     </para>
    </listitem>

    <listitem>
     <para>
      The API for user-defined GiST indexes has been changed. The
      Union and PickSplit methods are now passed a pointer to a
      special <structname>GistEntryVector</structname> structure,
      rather than a <type>bytea</type>.
     </para>
    </listitem>

   </itemizedlist>
  </sect2>

 <sect2>
  <title>Deprecated Features</title>

  <para>
    Some aspects of <productname>PostgreSQL</productname>'s behavior
    have been determined to be suboptimal. For the sake of backward
    compatibility these have not been removed in 8.0, but they are
    considered deprecated and will be removed in the next major
    release.
    </para>

   <itemizedlist>
    <listitem>
     <para>
      The 8.1 release will remove the <function>to_char()</> function
      for intervals.
     </para>
    </listitem>

     <listitem>
      <para>
       The server now warns of empty strings passed to
       <type>oid</type>/<type>float4</type>/<type>float8</type> data
       types, but continues to interpret them as zeroes as before.
       In the next major release, empty strings will be considered
       invalid input for these data types.
      </para>
     </listitem>

    <listitem>
     <para>
      By default, tables in <productname>PostgreSQL</productname> 8.0
      and earlier are created with <type>OID</>s. In the next release,
      this will <emphasis>not</emphasis> be the case: to create a table
      that contains <type>OID</>s, the <option>WITH OIDS</> clause must
      be specified or the <varname>default_with_oids</varname>
      configuration parameter must be set. Users are encouraged to
      explicitly specify <option>WITH OIDS</> if their tables
      require OIDs for compatibility with future releases of
      <productname>PostgreSQL</productname>.
     </para>
    </listitem>

   </itemizedlist>
  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    Below you will find a detailed account of the changes between
    release 8.0 and the previous major release.
   </para>

   <sect3>
    <title>Performance Improvements</title>
    <itemizedlist>

     <listitem>
      <para>
       Support cross-data-type index usage (Tom)
      </para>
      <para>
       Before this change, many queries would not use an index if the data
       types did not match exactly. This improvement makes index usage more
       intuitive and consistent.
      </para>
     </listitem>

     <listitem>
      <para>
       New buffer replacement strategy that improves caching (Jan)
      </para>
      <para>
       Prior releases used a least-recently-used (LRU) cache to keep
       recently referenced pages in memory. The LRU algorithm
       did not consider the number of times a specific cache entry was
       accessed, so large table scans could force out useful cache pages.
       The new cache algorithm uses four separate lists to track most
       recently used and most frequently used cache pages and dynamically
       optimize their replacement based on the work load. This should
       lead to much more efficient use of the shared buffer cache.
       Administrators who have tested shared buffer sizes in the past
       should retest with this new cache replacement policy.
      </para>
     </listitem>

     <listitem>
      <para>
       Add subprocess to write dirty buffers periodically to reduce
       checkpoint writes (Jan)
      </para>
      <para>
       In previous releases, the checkpoint process, which runs every few
       minutes, would write all dirty buffers to the operating system's
       buffer cache then flush all dirty operating system buffers to
       disk. This resulted in a periodic spike in disk usage that often
       hurt performance. The new code uses a background writer to trickle
       disk writes at a steady pace so checkpoints have far fewer dirty
       pages to write to disk. Also, the new code does not issue a global
       <function>sync()</> call, but instead <function>fsync()</>s just
       the files written since the last checkpoint. This should improve
       performance and minimize degradation during checkpoints.
      </para>
     </listitem>

     <listitem>
      <para>
       Add ability to prolong vacuum to reduce performance impact (Jan)
      </para>
      <para>
       On busy systems, <command>VACUUM</command> performs many I/O
       requests which can hurt performance for other users. This
       release allows you to slow down <command>VACUUM</command> to
       reduce its impact on other users, though this increases the
       total duration of <command>VACUUM</command>.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve B-tree index performance for duplicate keys (Dmitry Tkach, Tom)
      </para>
      <para>
       This improves the way indexes are scanned when many duplicate
       values exist in the index.
      </para>
     </listitem>

     <listitem>
      <para>
       Use dynamically-generated table size estimates while planning (Tom)
      </para>
      <para>
       Formerly the planner estimated table sizes using the values seen
       by the last <command>VACUUM</command> or <command>ANALYZE</command>,
       both as to physical table size (number of pages) and number of rows.
       Now, the current physical table size is obtained from the kernel,
       and the number of rows is estimated by multiplying the table size
       by the row density (rows per page) seen by the last
       <command>VACUUM</command> or <command>ANALYZE</command>.  This should
       produce more reliable estimates in cases where the table size has
       changed significantly since the last housekeeping command.
      </para>
     </listitem>

     <listitem>
      <para>
       Improved index usage with <literal>OR</> clauses (Tom)
      </para>
      <para>
       This allows the optimizer to use indexes in statements with many OR
       clauses that would not have been indexed in the past.  It can also use
       multi-column indexes where the first column is specified and the second
       column is part of an <literal>OR</> clause.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve matching of partial index clauses (Tom)
      </para>
      <para>
       The server is now smarter about using partial indexes in queries
       involving complex <option>WHERE</> clauses.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve performance of the GEQO optimizer (Tom)
      </para>
      <para>
       The GEQO optimizer is used to plan queries involving many tables (by
       default, twelve or more). This release speeds up the way queries are
       analyzed to decrease time spent in optimization.
      </para>
     </listitem>

     <listitem>
      <para>
       Miscellaneous optimizer improvements
      </para>
      <para>
       There is not room here to list all the minor improvements made, but
       numerous special cases work better than in prior releases.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve lookup speed for C functions (Tom)
      </para>
      <para>
       This release uses a hash table to lookup information for dynamically
       loaded C functions. This improves their speed so they perform nearly as
       quickly as functions that are built into the server executable.
      </para>
     </listitem>

     <listitem>
      <para>
       Add type-specific <command>ANALYZE</command> statistics
       capability (Mark Cave-Ayland)
      </para>
      <para>
       This feature allows more flexibility in generating statistics
       for nonstandard data types.
      </para>
     </listitem>

     <listitem>
      <para>
       <command>ANALYZE</command> now collects statistics for
       expression indexes (Tom)
      </para>
      <para>
       Expression indexes (also called functional indexes) allow users to
       index not just columns but the results of expressions and function
       calls. With this release, the optimizer can gather and use statistics
       about the contents of expression indexes.  This will greatly improve
       the quality of planning for queries in which an expression index is
       relevant.
      </para>
     </listitem>

     <listitem>
      <para>
       New two-stage sampling method for <command>ANALYZE</command>
       (Manfred Koizar)
      </para>
      <para>
       This gives better statistics when the density of valid rows is very
       different in different regions of a table.
      </para>
     </listitem>

     <listitem>
      <para>
       Speed up <command>TRUNCATE</command> (Tom)
      </para>
      <para>
       This buys back some of the performance loss observed in 7.4, while still
       keeping <command>TRUNCATE</command> transaction-safe.
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>Server Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add WAL file archiving and point-in-time recovery (Simon Riggs)
      </para>
     </listitem>

     <listitem>
      <para>
       Add tablespaces so admins can control disk layout (Gavin)
      </para>
     </listitem>

     <listitem>
      <para>
       Add a built-in log rotation program (Andreas Pflug)
      </para>
      <para>
       It is now possible to log server messages conveniently without
       relying on either <application>syslog</> or an external log
       rotation program.
      </para>
     </listitem>

     <listitem>
      <para>
       Add new read-only server configuration parameters to show server
       compile-time settings: <varname>block_size</>,
       <varname>integer_datetimes</>, <varname>max_function_args</>,
       <varname>max_identifier_length</>, <varname>max_index_keys</>  (Joe)
      </para>
     </listitem>

     <listitem>
      <para>
       Make quoting of <literal>sameuser</>, <literal>samegroup</>, and
       <literal>all</> remove special meaning of these terms in
       <filename>pg_hba.conf</> (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Use clearer IPv6 name <literal>::1/128</> for
       <literal>localhost</> in default <filename>pg_hba.conf</> (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Use CIDR format in <filename>pg_hba.conf</> examples (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Rename server configuration parameters <varname>SortMem</> and
       <varname>VacuumMem</> to <varname>work_mem</> and
       <varname>maintenance_work_mem</> (Old names still supported) (Tom)
      </para>
      <para>
       This change was made to clarify that bulk operations such as index and
       foreign key creation use <varname>maintenance_work_mem</>, while
       <varname>work_mem</> is for workspaces used during query execution.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow logging of session disconnections using server configuration
       <varname>log_disconnections</> (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Add new server configuration parameter <varname>log_line_prefix</> to
       allow control of information emitted in each log line (Andrew)
      </para>
      <para>
       Available information includes user name, database name, remote IP
       address, and session start time.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove server configuration parameters <varname>log_pid</>,
       <varname>log_timestamp</>, <varname>log_source_port</>; functionality
       superseded by <varname>log_line_prefix</> (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Replace the <varname>virtual_host</> and <varname>tcpip_socket</>
       parameters with a unified <varname>listen_addresses</> parameter
       (Andrew, Tom)
      </para>
      <para>
       <varname>virtual_host</> could only specify a single IP address to
       listen on.  <varname>listen_addresses</> allows multiple addresses
       to be specified.
      </para>
     </listitem>

     <listitem>
      <para>
       Listen on localhost by default, which eliminates the need for the
       <option>-i</> postmaster switch in many scenarios (Andrew)
      </para>
      <para>
       Listening on localhost (<literal>127.0.0.1</>) opens no new
       security holes but allows configurations like Windows and JDBC,
       which do not support local sockets, to work without special
       adjustments.
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <varname>syslog</> server configuration parameter, and add more
       logical <varname>log_destination</> variable to control log output
       location (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Change server configuration parameter <varname>log_statement</> to take
       values <varname>all</>, <varname>mod</>, <varname>ddl</>, or
       <varname>none</> to select which queries are logged (Bruce)
      </para>
      <para>
       This allows administrators to log only data definition changes or
       only data modification statements.
      </para>
     </listitem>

     <listitem>
      <para>
       Some logging-related configuration parameters could formerly be adjusted
       by ordinary users, but only in the <quote>more verbose</> direction.
       They are now treated more strictly: only superusers can set them.
       However, a superuser can use <command>ALTER USER</> to provide per-user
       settings of these values for non-superusers.  Also, it is now possible
       for superusers to set values of superuser-only configuration parameters
       via <literal>PGOPTIONS</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow configuration files to be placed outside the data directory (mlw)
      </para>
      <para>
       By default, configuration files are kept in the cluster's top directory.
       With this addition, configuration files can be placed outside the
       data directory, easing administration.
      </para>
     </listitem>

     <listitem>
      <para>
       Plan prepared queries only when first executed so constants can be
       used for statistics (Oliver Jowett)
      </para>
      <para>
       Prepared statements plan queries once and execute them many
       times. While prepared queries avoid the overhead of re-planning
       on each use, the quality of the plan suffers from not knowing the exact
       parameters to be used in the query.  In this release, planning of
       unnamed prepared statements is delayed until the first execution,
       and the actual parameter values of that execution are used as
       optimization hints.  This allows use of out-of-line parameter passing
       without incurring a performance penalty.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <command>DECLARE CURSOR</command> to take parameters
       (Oliver Jowett)
      </para>
      <para>
       It is now useful to issue <command>DECLARE CURSOR</command> in a
       <function>Parse</> message with parameters. The parameter values
       sent at <function>Bind</> time will be substituted into the
       execution of the cursor's query.
      </para>
     </listitem>

     <listitem>
      <para>
       Fix hash joins and aggregates of <type>inet</type> and
       <type>cidr</type> data types (Tom)
      </para>
      <para>
       Release 7.4 handled hashing of mixed <type>inet</type> and
       <type>cidr</type> values incorrectly.  (This bug did not exist
       in prior releases because they wouldn't try to hash either
       data type.)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <varname>log_duration</> print only when <varname>log_statement</>
       prints the query (Ed L.)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>Query Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add savepoints (nested transactions) (Alvaro)
      </para>
     </listitem>

     <listitem>
      <para>
       Unsupported isolation levels are now accepted and promoted to the
       nearest supported level (Peter)
      </para>
      <para>
       The SQL specification states that if a database doesn't support a
       specific isolation level, it should use the next more restrictive level.
       This change complies with that recommendation.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <command>BEGIN WORK</command> to specify transaction
       isolation levels like <command>START TRANSACTION</command> does
       (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix table permission checking for cases in which rules generate
       a query type different from the originally submitted query (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Implement dollar quoting to simplify single-quote usage (Andrew, Tom,
       David Fetter)
      </para>
      <para>
       In previous releases, because single quotes had to be used to
       quote a function's body, the use of single quotes inside the
       function text required use of two single quotes or other error-prone
       notations. With this release we add the ability to use "dollar
       quoting" to quote a block of text.  The ability to use different
       quoting delimiters at different nesting levels greatly simplifies
       the task of quoting correctly, especially in complex functions.
       Dollar quoting can be used anywhere quoted text is needed.
      </para>
     </listitem>

     <listitem>
      <para>
       Make <literal>CASE val WHEN compval1 THEN ...</> evaluate <literal>val</> only once (Tom)
      </para>
      <para>
       <option>CASE</> no longer evaluates the tested expression multiple
       times. This has benefits when the expression is complex or is
       volatile.
      </para>
     </listitem>

     <listitem>
      <para>
       Test <option>HAVING</> before computing target list of an
       aggregate query (Tom)
      </para>
      <para>
       Fixes improper failure of cases such as <literal>SELECT SUM(win)/SUM(lose)
       ... GROUP BY ... HAVING SUM(lose) &gt; 0</>.  This should work but formerly
       could fail with divide-by-zero.
      </para>
     </listitem>

     <listitem>
      <para>
       Replace <varname>max_expr_depth</> parameter with
       <varname>max_stack_depth</> parameter, measured in kilobytes of stack
       size (Tom)
      </para>
      <para>
      This gives us a fairly bulletproof defense against crashing due to
      runaway recursive functions. Instead of measuring the depth of expression
      nesting, we now directly measure the size of the execution stack.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow arbitrary row expressions (Tom)
      </para>
      <para>
       This release allows SQL expressions to contain arbitrary composite
       types, that is, row values. It also allows functions to more easily
       take rows as arguments and return row values.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <option>LIKE</>/<option>ILIKE</> to be used as the operator
       in row and subselect comparisons (Fabien Coelho)
      </para>
     </listitem>

     <listitem>
      <para>
       Avoid locale-specific case conversion of basic ASCII letters in
       identifiers and keywords (Tom)
      </para>
      <para>
       This solves the <quote>Turkish problem</> with mangling of words
       containing <literal>I</> and  <literal>i</>.  Folding of characters
       outside the 7-bit-ASCII set is still locale-aware.
      </para>
     </listitem>

     <listitem>
      <para>
       Improve syntax error reporting (Fabien, Tom)
      </para>
      <para>
       Syntax error reports are more useful than before.
      </para>
     </listitem>

     <listitem>
      <para>
       Change <command>EXECUTE</command> to return a completion tag
       matching the executed statement (Kris Jurka)
      </para>
      <para>
       Previous releases return an <command>EXECUTE</command> tag for
       any <command>EXECUTE</command> call. In this release, the tag
       returned will reflect the command executed.
      </para>
     </listitem>

     <listitem>
      <para>
       Avoid emitting <option>NATURAL CROSS JOIN</> in rule listings (Tom)
      </para>
      <para>
       Such a clause makes no logical sense, but in some cases the rule
       decompiler formerly produced this syntax.
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>Object Manipulation Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Add <command>COMMENT ON</> for casts, conversions, languages,
       operator classes, and large objects (Christopher)
      </para>
     </listitem>

     <listitem>
      <para>
       Add new server configuration parameter <varname>default_with_oids</> to
       control whether tables are created with <type>OID</>s by default (Neil)
      </para>
      <para>
       This allows administrators to control whether <command>CREATE
       TABLE</command> commands create tables with or without <type>OID</>
       columns by default.  (Note: the current factory default setting for
       <varname>default_with_oids</> is <literal>TRUE</>, but the default
       will become <literal>FALSE</> in future releases.)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <option>WITH</> / <option>WITHOUT OIDS</> clause to
       <command>CREATE TABLE AS</command> (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <command>ALTER TABLE DROP COLUMN</> to drop an <type>OID</>
       column (<command>ALTER TABLE SET WITHOUT OIDS</> still works)
       (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow composite types as table columns (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <command>ALTER ... ADD COLUMN</> with defaults and
       <option>NOT NULL</> constraints; works per SQL spec (Rod)
      </para>
      <para>
       It is now possible for <option>ADD COLUMN</> to create a column
       that is not initially filled with NULLs, but with a specified
       default value.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <command>ALTER COLUMN TYPE</> to change column's type (Rod)
      </para>
      <para>
       It is now possible to alter a column's data type without dropping
       and re-adding the column.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow multiple <command>ALTER</> actions in a single <command>ALTER
       TABLE</command> command (Rod)
      </para>
      <para>
       This is particularly useful for <command>ALTER</> commands that
       rewrite the table (which include <option>ALTER COLUMN TYPE</> and
       <option>ADD COLUMN</> with a default). By grouping
       <command>ALTER</> commands together, the table need be rewritten
       only once.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <command>ALTER TABLE</command> to add <type>SERIAL</type>
       columns (Tom)
      </para>
      <para>
       This falls out from the new capability of specifying defaults for new
       columns.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow changing the owners of aggregates, conversions, databases,
       functions, operators, operator classes, schemas, types, and tablespaces
       (Christopher, Euler Taveira de Oliveira)
      </para>
      <para>
       Previously this required modifying the system tables directly.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow temporary object creation to be limited to <option>SECURITY
       DEFINER</> functions (Sean Chittenden)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <option>ALTER TABLE ... SET WITHOUT CLUSTER</> (Christopher)
      </para>
      <para>
       Prior to this release, there was no way to clear an auto-cluster
       specification except to modify the system tables.
      </para>
     </listitem>

     <listitem>
      <para>
       Constraint/Index/<type>SERIAL</> names are now
       <replaceable>table_column_type</>
       with numbers appended to guarantee uniqueness within the schema
       (Tom)
      </para>
      <para>
       The SQL specification states that such names should be unique
       within a schema.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>pg_get_serial_sequence()</> to return a
       <type>SERIAL</> column's sequence name (Christopher)
      </para>
      <para>
       This allows automated scripts to reliably find the <type>SERIAL</>
       sequence name.
      </para>
     </listitem>

     <listitem>
      <para>
       Warn when primary/foreign key data type mismatch requires costly lookup
      </para>
     </listitem>

     <listitem>
      <para>
       New <command>ALTER INDEX</> command to allow moving of indexes
       between tablespaces (Gavin)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <command>ALTER TABLE OWNER</> change dependent sequence
       ownership too (Alvaro)
      </para>
     </listitem>


    </itemizedlist>
   </sect3>


   <sect3>
    <title>Utility Command Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Allow <command>CREATE SCHEMA</command> to create triggers,
       indexes, and sequences (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <option>ALSO</> keyword to <command>CREATE RULE</command> (Fabien
       Coelho)
      </para>
      <para>
       This allows <option>ALSO</> to be added to rule creation to contrast it with
       <option>INSTEAD</> rules.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <option>NOWAIT</> option to <command>LOCK</command> (Tatsuo)
      </para>
      <para>
       This allows the <command>LOCK</command> command to fail if it
       would have to wait for the requested lock.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <command>COPY</command> to read and write
       comma-separated-value (CSV) files (Andrew, Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Generate error if the <command>COPY</command> delimiter and NULL
       string conflict (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       <command>GRANT</command>/<command>REVOKE</command> behavior
       follows the SQL spec more closely
      </para>
     </listitem>

     <listitem>
      <para>
       Avoid locking conflict between <command>CREATE INDEX</command>
       and <command>CHECKPOINT</command> (Tom)
      </para>
      <para>
       In 7.3 and 7.4, a long-running B-tree index build could block concurrent
       <command>CHECKPOINT</>s from completing, thereby causing WAL bloat because the
       WAL log could not be recycled.
      </para>
     </listitem>

     <listitem>
      <para>
       Database-wide <command>ANALYZE</command> does not hold locks
       across tables (Tom)
      </para>
      <para>
       This reduces the potential for deadlocks against other backends
       that want exclusive locks on tables.  To get the benefit of this
       change, do not execute database-wide <command>ANALYZE</command>
       inside a transaction block (<command>BEGIN</command> block); it
       must be able to commit and start a new transaction for each
       table.
      </para>
     </listitem>

     <listitem>
      <para>
       <command>REINDEX</command> does not exclusively lock the index's
       parent table anymore
      </para>
      <para>
       The index itself is still exclusively locked, but readers of the
       table can continue if they are not using the particular index
       being rebuilt.
      </para>
     </listitem>

     <listitem>
      <para>
       Erase MD5 user passwords when a user is renamed (Bruce)
      </para>
      <para>
       <productname>PostgreSQL</productname> uses the user name as salt
       when encrypting passwords via MD5. When a user's name is changed,
       the salt will no longer match the stored MD5 password, so the
       stored password becomes useless.  In this release a notice is
       generated and the password is cleared.  A new password must then
       be assigned if the user is to be able to log in with a password.
      </para>
     </listitem>

     <listitem>
      <para>
       New <application>pg_ctl</> <option>kill</> option for Windows (Andrew)
      </para>
      <para>
       Windows does not have a <literal>kill</> command to send signals to
       backends so this capability was added to <application>pg_ctl</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Information schema improvements
      </para>
     </listitem>

     <listitem>
      <para>
       Add <option>--pwfile</> option to
       <application>initdb</application> so the initial password can be
       set by GUI tools (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Detect locale/encoding mismatch in
       <application>initdb</application> (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <option>register</> command to <application>pg_ctl</> to
       register Windows operating system service (Dave Page)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>Data Type and Function Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       More complete support for composite types (row types)  (Tom)
      </para>
      <para>
       Composite values can be used in many places where only scalar values
       worked before.
      </para>
     </listitem>

     <listitem>
      <para>
       Reject nonrectangular array values as erroneous (Joe)
      </para>
      <para>
       Formerly, <function>array_in</> would silently build a
       surprising result.
      </para>
     </listitem>

      <listitem>
       <para>
        Overflow in integer arithmetic operations is now detected (Tom)
       </para>
      </listitem>

      <listitem>
       <para>
        The arithmetic operators associated with the single-byte
        <type>"char"</> data type have been removed.
       </para>
       <para>
        Formerly, the parser would select these operators in many situations
        where an <quote>unable to select an operator</> error would be more
        appropriate, such as <literal>null * null</>.  If you actually want
        to do arithmetic on a <type>"char"</> column, you can cast it to
        integer explicitly.
       </para>
      </listitem>

     <listitem>
       <para>
        Syntax checking of array input values considerably tightened up (Joe)
       </para>
      <para>
        Junk that was previously allowed in odd places with odd results
        now causes an <literal>ERROR</>, for example, non-whitespace
        after the closing right brace.
       </para>
     </listitem>

     <listitem>
       <para>
        Empty-string array element values must now be written as
        <literal>""</>, rather than writing nothing (Joe)
       </para>
      <para>
        Formerly, both ways of writing an empty-string element value were
        allowed, but now a quoted empty string is required.  The case where
        nothing at all appears will probably be considered to be a NULL
        element value in some future release.
       </para>
     </listitem>

     <listitem>
       <para>
        Array element trailing whitespace is now ignored (Joe)
       </para>
      <para>
        Formerly leading whitespace was ignored, but trailing whitespace
        between an element value and the delimiter or right brace was
        significant.  Now trailing whitespace is also ignored.
       </para>
     </listitem>

     <listitem>
      <para>
       Emit array values with explicit array bounds when lower bound is not one
       (Joe)
      </para>
     </listitem>

     <listitem>
      <para>
       Accept <literal>YYYY-monthname-DD</> as a date string (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <function>netmask</> and <function>hostmask</> functions
       return maximum-length mask length (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Change factorial function to return <type>numeric</type> (Gavin)
      </para>
      <para>
       Returning <type>numeric</type> allows the factorial function to
       work for a wider range of input values.
      </para>
     </listitem>

     <listitem>
      <para>
       <function>to_char</>/<function>to_date()</> date conversion
       improvements (Kurt Roeckx, Fabien Coelho)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <function>length()</> disregard trailing spaces in
       <type>CHAR(n)</> (Gavin)
      </para>
      <para>
       This change was made to improve consistency: trailing spaces are
       semantically insignificant in <type>CHAR(n)</> data, so they
       should not be counted by <function>length()</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Warn about empty string being passed to
       <type>OID</>/<type>float4</>/<type>float8</> data types (Neil)
      </para>
      <para>
       8.1 will throw an error instead.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow leading or trailing whitespace in
       <type>int2</>/<type>int4</>/<type>int8</>/<type>float4</>/<type>float8</>
       input routines
       (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Better support for IEEE <literal>Infinity</> and <literal>NaN</>
       values in <type>float4</type>/<type>float8</type> (Neil)
      </para>
      <para>
       These should now work on all platforms that support IEEE-compliant
       floating point arithmetic.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <option>week</> option to <function>date_trunc()</> (Robert Creager)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <function>to_char</function> for <literal>1 BC</>
       (previously it returned <literal>1 AD</>) (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <function>date_part(year)</> for BC dates (previously it
       returned one less than the correct year) (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <function>date_part()</> to return the proper millennium and
       century (Fabien Coelho)
      </para>
      <para>
       In previous versions, the century and millennium results had a wrong
       number and started in the wrong year, as compared to standard
       reckoning of such things.
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>ceiling()</> as an alias for <function>ceil()</>,
       and <function>power()</> as an alias for <function>pow()</> for
       standards compliance (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Change <function>ln()</>, <function>log()</>,
       <function>power()</>, and <function>sqrt()</> to emit the correct
       <literal>SQLSTATE</> error codes for certain error conditions, as
       specified by SQL:2003 (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>width_bucket()</> function as defined by SQL:2003 (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>generate_series()</> functions to simplify working
       with numeric sets (Joe)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix <function>upper/lower/initcap()</> functions to work with
       multibyte encodings (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add boolean and bitwise integer <option>AND</>/<option>OR</>
       aggregates (Fabien Coelho)
      </para>
     </listitem>

     <listitem>
      <para>
       New session information functions to return network addresses for client
       and server (Sean Chittenden)
      </para>
     </listitem>

     <listitem>
      <para>
       Add function to determine the area of a closed path (Sean Chittenden)
      </para>
     </listitem>

     <listitem>
      <para>
       Add function to send cancel request to other backends (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <type>interval</> plus <type>datetime</> operators (Tom)
      </para>
      <para>
       The reverse ordering, <type>datetime</> plus <type>interval</>,
       was already supported, but both are required by the SQL standard.
      </para>
     </listitem>

     <listitem>
      <para>
       Casting an integer to <type>BIT(N)</> selects the rightmost N bits
       of the integer
       (Tom)
      </para>
      <para>
       In prior releases, the leftmost N bits were selected, but this was
       deemed unhelpful, not to mention inconsistent with casting from bit
       to int.
      </para>
     </listitem>

     <listitem>
      <para>
       Require <type>CIDR</> values to have all nonmasked bits be zero
       (Kevin Brintnall)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>Server-Side Language Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       In <literal>READ COMMITTED</> serialization mode, volatile functions
       now see the results of concurrent transactions committed up to the
       beginning of each statement within the function, rather than up to the
       beginning of the interactive command that called the function.
      </para>
     </listitem>

     <listitem>
      <para>
       Functions declared <literal>STABLE</> or <literal>IMMUTABLE</> always
       use the snapshot of the calling query, and therefore do not see the
       effects of actions taken after the calling query starts, whether in
       their own transaction or other transactions.  Such a function must be
       read-only, too, meaning that it cannot use any SQL commands other than
       <command>SELECT</>.  There is a considerable performance gain from
       declaring a function <literal>STABLE</> or <literal>IMMUTABLE</>
       rather than <literal>VOLATILE</>.
      </para>
     </listitem>

     <listitem>
      <para>
       Nondeferred <option>AFTER</> triggers are now fired immediately
       after completion of the triggering query, rather than upon
       finishing the current interactive command. This makes a difference
       when the triggering query occurred within a function: the trigger
       is invoked before the function proceeds to its next operation. For
       example, if a function inserts a new row into a table, any
       nondeferred foreign key checks occur before proceeding with the
       function.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow function parameters to be declared with names (Dennis Bj&ouml;rklund)
      </para>
      <para>
       This allows better documentation of functions.  Whether the names
       actually do anything depends on the specific function language
       being used.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow PL/pgSQL parameter names to be referenced in the function (Dennis Bj&ouml;rklund)
      </para>
      <para>
       This basically creates an automatic alias for each named parameter.
      </para>
     </listitem>

     <listitem>
      <para>
       Do minimal syntax checking of PL/pgSQL functions at creation time (Tom)
      </para>
      <para>
       This allows us to catch simple syntax errors sooner.
      </para>
     </listitem>

     <listitem>
      <para>
       More support for composite types (row and record variables) in PL/pgSQL
      </para>
      <para>
       For example, it now works to pass a rowtype variable to another function
       as a single variable.
      </para>
     </listitem>

     <listitem>
      <para>
       Default values for PL/pgSQL variables can now reference previously
       declared variables
      </para>
     </listitem>

     <listitem>
      <para>
       Improve parsing of PL/pgSQL FOR loops (Tom)
      </para>
      <para>
       Parsing is now driven by presence of <literal>".."</> rather than
       data type of <option>FOR</> variable. This makes no difference for
       correct functions, but should result in more understandable error
       messages when a mistake is made.
      </para>
     </listitem>

     <listitem>
      <para>
       Major overhaul of PL/Perl server-side language (Command Prompt, Andrew Dunstan)
      </para>
     </listitem>

     <listitem>
      <para>
       In PL/Tcl, SPI commands are now run in subtransactions.  If an error
       occurs, the subtransaction is cleaned up and the error is reported
       as an ordinary Tcl error, which can be trapped with <literal>catch</>.
       Formerly, it was not possible to catch such errors.
      </para>
     </listitem>

     <listitem>
      <para>
       Accept <command>ELSEIF</> in PL/pgSQL (Neil)
      </para>
      <para>
       Previously PL/pgSQL only allowed <command>ELSIF</>, but many people
       are accustomed to spelling this keyword <command>ELSEIF</>.
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title><application>psql</> Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Improve <application>psql</> information display about database
       objects (Christopher)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <application>psql</> to display group membership in
       <command>\du</> and <command>\dg</> (Markus Bertheau)
      </para>
     </listitem>

     <listitem>
      <para>
       Prevent <application>psql</> <command>\dn</command> from showing
       temporary schemas (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <application>psql</> to handle tilde user expansion for file
       names (Zach Irmen)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <application>psql</> to display fancy prompts, including
       color, via <application>readline</> (Reece Hart, Chet Ramey)
      </para>
     </listitem>

     <listitem>
      <para>
       Make <application>psql</> <command>\copy</> match <command>COPY</command> command syntax
       fully (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Show the location of syntax errors (Fabien Coelho, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <command>CLUSTER</command> information to <application>psql</>
       <command>\d</> display
       (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Change <application>psql</> <command>\copy stdin/stdout</> to read
       from command input/output (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <option>pstdin</>/<option>pstdout</> to read from
       <application>psql</>'s <literal>stdin</>/<literal>stdout</> (Mark
       Feit)
      </para>
     </listitem>

     <listitem>
      <para>
       Add global <application>psql</> configuration file, <filename>psqlrc.sample</filename>
       (Bruce)
      </para>
      <para>
       This allows a central file where global <application>psql</> startup commands can
       be stored.
      </para>
     </listitem>

     <listitem>
      <para>
       Have <application>psql</> <command>\d+</> indicate if the table
       has an <type>OID</> column (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       On Windows, use binary mode in <application>psql</> when reading files so control-Z
       is not seen as end-of-file
      </para>
     </listitem>

     <listitem>
      <para>
       Have <command>\dn+</> show permissions and description for schemas (Dennis
       Bj&ouml;rklund)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve tab completion support (Stefan Kaltenbrunn, Greg Sabino Mullane)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow boolean settings to be set using upper or lower case (Michael Paesold)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title><application>pg_dump</> Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Use dependency information to improve the reliability of
       <application>pg_dump</> (Tom)
      </para>
      <para>
       This should solve the longstanding problems with related objects
       sometimes being dumped in the wrong order.
      </para>
     </listitem>

     <listitem>
      <para>
       Have <application>pg_dump</> output objects in alphabetical order if possible (Tom)
      </para>
      <para>
       This should make it easier to identify changes between
       dump files.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <application>pg_restore</> to ignore some SQL errors (Fabien Coelho)
      </para>
      <para>
       This makes <application>pg_restore</>'s behavior similar to the
       results of feeding a <application>pg_dump</> output script to
       <application>psql</>. In most cases, ignoring errors and plowing
       ahead is the most useful thing to do. Also added was a pg_restore
       option to give the old behavior of exiting on an error.
      </para>
     </listitem>

     <listitem>
      <para>
       <application>pg_restore</> <option>-l</> display now includes
       objects' schema names
      </para>
     </listitem>

     <listitem>
      <para>
       New begin/end markers in <application>pg_dump</> text output (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Add start/stop times for
       <application>pg_dump</>/<application>pg_dumpall</> in verbose mode
       (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow most <application>pg_dump</> options in
       <application>pg_dumpall</> (Christopher)
      </para>
     </listitem>

     <listitem>
      <para>
       Have <application>pg_dump</> use <command>ALTER OWNER</> rather
       than <command>SET SESSION AUTHORIZATION</> by default
       (Christopher)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>libpq Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Make libpq's <option>SIGPIPE</> handling thread-safe (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>PQmbdsplen()</> which returns the display length
       of a character (Tatsuo)
      </para>
     </listitem>

     <listitem>
      <para>
       Add thread locking to <application>SSL</> and
       <application>Kerberos</> connections (Manfred Spraul)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <function>PQoidValue()</>, <function>PQcmdTuples()</>, and
       <function>PQoidStatus()</> to work on <command>EXECUTE</command>
       commands (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>PQserverVersion()</> to provide more convenient
       access to the server version number (Greg Sabino Mullane)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <function>PQprepare/PQsendPrepared()</> functions to support
       preparing statements without necessarily specifying the data types
       of their parameters (Abhijit Menon-Sen)
      </para>
     </listitem>

     <listitem>
      <para>
       Many ECPG improvements, including <command>SET DESCRIPTOR</> (Michael)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>Source Code Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Allow the database server to run natively on Windows (Claudio, Magnus, Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Shell script commands converted to C versions for Windows support (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Create an extension makefile framework (Fabien Coelho, Peter)
      </para>
      <para>
       This simplifies the task of building extensions outside the original
       source tree.
      </para>
     </listitem>

     <listitem>
      <para>
       Support relocatable installations (Bruce)
      </para>
      <para>
       Directory paths for installed files (such as the
       <filename>/share</> directory) are now computed relative to the
       actual location of the executables, so that an installation tree
       can be moved to another place without reconfiguring and
       rebuilding.
      </para>
     </listitem>

     <listitem>
      <para>
       Use <option>--with-docdir</> to choose installation location of documentation; also
       allow <option>--infodir</> (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Add <option>--without-docdir</> to prevent installation of documentation (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Upgrade to <application>DocBook</> V4.2 SGML (Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       New <literal>PostgreSQL</> <application>CVS</> tag (Marc)
      </para>
      <para>
       This was done to make it easier for organizations to manage their
       own copies of the <productname>PostgreSQL</productname>
       <application>CVS</> repository. File version stamps from the master
       repository will not get munged by checking into or out of a copied
       repository.
      </para>
     </listitem>

     <listitem>
      <para>
       Clarify locking code (Manfred Koizar)
      </para>
     </listitem>

     <listitem>
      <para>
       Buffer manager cleanup (Neil)
      </para>
     </listitem>

     <listitem>
      <para>
       Decouple platform tests from CPU spinlock code (Bruce, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Add inlined test-and-set code on PA-RISC for <application>gcc</>
       (ViSolve, Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Improve i386 spinlock code (Manfred Spraul)
      </para>
     </listitem>

     <listitem>
      <para>
       Clean up spinlock assembly code to avoid warnings from newer
       <application>gcc</> releases (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Remove JDBC from source tree; now a separate project
      </para>
     </listitem>

     <listitem>
      <para>
       Remove the libpgtcl client interface; now a separate project
      </para>
     </listitem>

     <listitem>
      <para>
       More accurately estimate memory and file descriptor usage (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Improvements to the Mac OS X startup scripts (Ray A.)
      </para>
     </listitem>

     <listitem>
      <para>
       New <function>fsync()</> test program (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Major documentation improvements (Neil, Peter)
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <application>pg_encoding</application>; not needed
       anymore
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <application>pg_id</application>; not needed anymore
      </para>
     </listitem>

     <listitem>
      <para>
       Remove <application>initlocation</application>; not needed
       anymore
      </para>
     </listitem>

     <listitem>
      <para>
       Auto-detect thread flags (no more manual testing) (Bruce)
      </para>
     </listitem>

     <listitem>
      <para>
       Use Olson's public domain <application>timezone</> library (Magnus)
      </para>
     </listitem>

     <listitem>
      <para>
       With threading enabled, use thread flags on Unixware for
       backend executables too (Bruce)
      </para>
      <para>
       Unixware cannot mix threaded and nonthreaded object files in the
       same executable, so everything must be compiled as threaded.
      </para>
     </listitem>

     <listitem>
      <para>
       <application>psql</> now uses a <application>flex</>-generated
       lexical analyzer to process command strings
      </para>
     </listitem>

     <listitem>
      <para>
       Reimplement the linked list data structure used throughout the
       backend (Neil)
      </para>
      <para>
       This improves performance by allowing list append and length
       operations to be more efficient.
      </para>
     </listitem>

     <listitem>
      <para>
       Allow dynamically loaded modules to create their own server configuration
       parameters (Thomas Hallgren)
      </para>
     </listitem>

     <listitem>
      <para>
       New Brazilian version of FAQ (Euler Taveira de Oliveira)
      </para>
     </listitem>

     <listitem>
      <para>
       Add French FAQ (Guillaume Lelarge)
      </para>
     </listitem>

     <listitem>
      <para>
       New <application>pgevent</> for Windows logging
      </para>
     </listitem>

     <listitem>
      <para>
       Make libpq and ECPG build as proper shared libraries on OS X (Tom)
      </para>
     </listitem>

    </itemizedlist>
   </sect3>


   <sect3>
    <title>Contrib Changes</title>
    <itemizedlist>

     <listitem>
      <para>
       Overhaul of <filename>contrib/dblink</> (Joe)
      </para>
     </listitem>

     <listitem>
      <para>
       <filename>contrib/dbmirror</> improvements (Steven Singer)
      </para>
     </listitem>

     <listitem>
      <para>
       New <filename>contrib/xml2</> (John Gray, Torchbox)
      </para>
     </listitem>

     <listitem>
      <para>
       Updated <filename>contrib/mysql</filename>
      </para>
     </listitem>

     <listitem>
      <para>
       New version of <filename>contrib/btree_gist</> (Teodor)
      </para>
     </listitem>

     <listitem>
      <para>
       New <filename>contrib/trgm</>, trigram matching for
       <productname>PostgreSQL</productname> (Teodor)
      </para>
     </listitem>

     <listitem>
      <para>
       Many <filename>contrib/tsearch2</> improvements (Teodor)
      </para>
     </listitem>

     <listitem>
      <para>
       Add double metaphone to <filename>contrib/fuzzystrmatch</> (Andrew)
      </para>
     </listitem>

     <listitem>
      <para>
       Allow <filename>contrib/pg_autovacuum</> to run as a Windows service (Dave Page)
      </para>
     </listitem>

     <listitem>
      <para>
       Add functions to <filename>contrib/dbsize</> (Andreas Pflug)
      </para>
     </listitem>

     <listitem>
      <para>
       Removed <filename>contrib/pg_logger</>: obsoleted by integrated logging
       subprocess
      </para>
     </listitem>

     <listitem>
      <para>
       Removed <filename>contrib/rserv</>: obsoleted by various separate projects
      </para>
     </listitem>

    </itemizedlist>
   </sect3>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-18">
  <title>Release 7.4.18</title>

  <note>
  <title>Release date</title>
  <simpara>2007-09-17</simpara>
  </note>

  <para>
   This release contains fixes from 7.4.17.
  </para>

  <sect2>
   <title>Migration to Version 7.4.18</title>

   <para>
    A dump/restore is not required for those running 7.4.X.  However,
    if you are upgrading from a version earlier than 7.4.11, see the release
    notes for 7.4.11.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Prevent index corruption when a transaction inserts rows and
      then aborts close to the end of a concurrent <command>VACUUM</>
      on the same table (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Make <command>CREATE DOMAIN ... DEFAULT NULL</> work properly (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix excessive logging of <acronym>SSL</> error messages (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix crash when <varname>log_min_error_statement</> logging runs out
      of memory (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Prevent <command>CLUSTER</> from failing
      due to attempting to process temporary tables of other sessions (Alvaro)
     </para>
    </listitem>

    <listitem>
     <para>
      Require non-superusers who use <filename>/contrib/dblink</> to use only
      password authentication, as a security measure (Joe)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-17">
  <title>Release 7.4.17</title>

  <note>
  <title>Release date</title>
  <simpara>2007-04-23</simpara>
  </note>

  <para>
   This release contains fixes from 7.4.16,
   including a security fix.
  </para>

  <sect2>
   <title>Migration to Version 7.4.17</title>

   <para>
    A dump/restore is not required for those running 7.4.X.  However,
    if you are upgrading from a version earlier than 7.4.11, see the release
    notes for 7.4.11.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
    <para>
     Support explicit placement of the temporary-table schema within
     <varname>search_path</>, and disable searching it for functions
     and operators (Tom)
    </para>
    <para>
     This is needed to allow a security-definer function to set a
     truly secure value of <varname>search_path</>.  Without it,
     an unprivileged SQL user can use temporary objects to execute code
     with the privileges of the security-definer function (CVE-2007-2138).
     See <command>CREATE FUNCTION</> for more information.
    </para>
    </listitem>

    <listitem>
    <para>
     <filename>/contrib/tsearch2</> crash fixes (Teodor)
    </para>
    </listitem>

    <listitem>
    <para>
     Fix potential-data-corruption bug in how <command>VACUUM FULL</> handles
     <command>UPDATE</> chains (Tom, Pavan Deolasee)
    </para>
    </listitem>

    <listitem>
    <para>
     Fix PANIC during enlargement of a hash index (bug introduced in 7.4.15)
     (Tom)
    </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-16">
  <title>Release 7.4.16</title>

  <note>
  <title>Release date</title>
  <simpara>2007-02-05</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.15, including
   a security fix.
  </para>

  <sect2>
   <title>Migration to Version 7.4.16</title>

   <para>
    A dump/restore is not required for those running 7.4.X.  However,
    if you are upgrading from a version earlier than 7.4.11, see the release
    notes for 7.4.11.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
    <para>
     Remove security vulnerability that allowed connected users
     to read backend memory (Tom)
    </para>
    <para>
     The vulnerability involves suppressing the normal check that a SQL
     function returns the data type it's declared to, or changing the
     data type of a table column used in a SQL function (CVE-2007-0555).
     This error can easily be exploited to cause a backend crash, and in
     principle might be used to read database content that the user
     should not be able to access.
    </para>
    </listitem>

    <listitem>
    <para>
     Fix rare bug wherein btree index page splits could fail
     due to choosing an infeasible split point (Heikki Linnakangas)
    </para>
    </listitem>

    <listitem>
    <para>
     Fix for rare Assert() crash triggered by <literal>UNION</> (Tom)
    </para>
    </listitem>

    <listitem>
    <para>
     Tighten security of multi-byte character processing for UTF8 sequences
     over three bytes long (Tom)
    </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-15">
  <title>Release 7.4.15</title>

  <note>
  <title>Release date</title>
  <simpara>2007-01-08</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.14.
  </para>

  <sect2>
   <title>Migration to Version 7.4.15</title>

   <para>
    A dump/restore is not required for those running 7.4.X.  However,
    if you are upgrading from a version earlier than 7.4.11, see the release
    notes for 7.4.11.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Improve handling of <function>getaddrinfo()</> on AIX (Tom)
     </para>

     <para>
      This fixes a problem with starting the statistics collector,
      among other things.
     </para>
    </listitem>

     <listitem>
      <para>
       Fix <quote>failed to re-find parent key</> errors in
       <command>VACUUM</> (Tom)
      </para>
     </listitem>

     <listitem>
      <para>
       Fix bugs affecting multi-gigabyte hash indexes (Tom)
      </para>
     </listitem>

    <listitem>
     <para>
      Fix error when constructing an <literal>ARRAY[]</> made up of multiple
      empty elements (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      <function>to_number()</> and <function>to_char(numeric)</>
      are now <literal>STABLE</>, not <literal>IMMUTABLE</>, for
      new <application>initdb</> installs (Tom)
     </para>

     <para>
      This is because <varname>lc_numeric</> can potentially
      change the output of these functions.
     </para>
    </listitem>

    <listitem>
     <para>
      Improve index usage of regular expressions that use parentheses (Tom)
     </para>

     <para>
      This improves <application>psql</> <literal>\d</> performance also.
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-14">
  <title>Release 7.4.14</title>

  <note>
  <title>Release date</title>
  <simpara>2006-10-16</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.13.
  </para>

  <sect2>
   <title>Migration to Version 7.4.14</title>

   <para>
    A dump/restore is not required for those running 7.4.X.  However,
    if you are upgrading from a version earlier than 7.4.11, see the release
    notes for 7.4.11.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Fix core dump when an untyped literal is taken as
ANYARRAY</para></listitem>
<listitem><para>Fix <function>string_to_array()</> to handle overlapping
 matches for the separator string</para>
<para>For example, <literal>string_to_array('123xx456xxx789', 'xx')</>.
</para></listitem>
<listitem><para>Fix corner cases in pattern matching for
 <application>psql</>'s <literal>\d</> commands</para></listitem>
<listitem><para>Fix index-corrupting bugs in /contrib/ltree
 (Teodor)</para></listitem>
<listitem><para>Fix backslash escaping in /contrib/dbmirror</para></listitem>
<listitem><para>Adjust regression tests for recent changes in US DST laws
</para> </listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-13">
  <title>Release 7.4.13</title>

  <note>
  <title>Release date</title>
  <simpara>2006-05-23</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.12,
   including patches for extremely serious security issues.
  </para>

  <sect2>
   <title>Migration to Version 7.4.13</title>

   <para>
    A dump/restore is not required for those running 7.4.X.  However,
    if you are upgrading from a version earlier than 7.4.11, see the release
    notes for 7.4.11.
   </para>

   <para>
    Full security against the SQL-injection attacks described in
    CVE-2006-2313 and CVE-2006-2314 might require changes in application
    code.  If you have applications that embed untrustworthy strings
    into SQL commands, you should examine them as soon as possible to
    ensure that they are using recommended escaping techniques.  In
    most cases, applications should be using subroutines provided by
    libraries or drivers (such as <application>libpq</>'s
    <function>PQescapeStringConn()</>) to perform string escaping,
    rather than relying on <foreignphrase>ad hoc</> code to do it.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Change the server to reject invalidly-encoded multibyte
characters in all cases (Tatsuo, Tom)</para>
<para>While <productname>PostgreSQL</> has been moving in this direction for
some time, the checks are now applied uniformly to all encodings and all
textual input, and are now always errors not merely warnings.  This change
defends against SQL-injection attacks of the type described in CVE-2006-2313.
</para></listitem>

<listitem><para>Reject unsafe uses of <literal>\'</> in string literals</para>
<para>As a server-side defense against SQL-injection attacks of the type
described in CVE-2006-2314, the server now only accepts <literal>''</> and not
<literal>\'</> as a representation of ASCII single quote in SQL string
literals.  By default, <literal>\'</> is rejected only when
<varname>client_encoding</> is set to a client-only encoding (SJIS, BIG5, GBK,
GB18030, or UHC), which is the scenario in which SQL injection is possible.
A new configuration parameter <varname>backslash_quote</> is available to
adjust this behavior when needed.  Note that full security against
CVE-2006-2314 might require client-side changes; the purpose of
<varname>backslash_quote</> is in part to make it obvious that insecure
clients are insecure.
</para></listitem>

<listitem><para>Modify <application>libpq</>'s string-escaping routines to be
aware of encoding considerations and
<varname>standard_conforming_strings</></para>
<para>This fixes <application>libpq</>-using applications for the security
issues described in CVE-2006-2313 and CVE-2006-2314, and also future-proofs
them against the planned changeover to SQL-standard string literal syntax.
Applications that use multiple <productname>PostgreSQL</> connections
concurrently should migrate to <function>PQescapeStringConn()</> and
<function>PQescapeByteaConn()</> to ensure that escaping is done correctly
for the settings in use in each database connection.  Applications that
do string escaping <quote>by hand</> should be modified to rely on library
routines instead.
</para></listitem>

<listitem><para>Fix some incorrect encoding conversion functions</para>
<para><function>win1251_to_iso</>, <function>alt_to_iso</>,
<function>euc_tw_to_big5</>, <function>euc_tw_to_mic</>,
<function>mic_to_euc_tw</> were all broken to varying
extents.
</para></listitem>

<listitem><para>Clean up stray remaining uses of <literal>\'</> in strings
(Bruce, Jan)</para></listitem>

<listitem><para>Fix bug that sometimes caused OR'd index scans to
miss rows they should have returned</para></listitem>

<listitem><para>Fix WAL replay for case where a btree index has been
truncated</para></listitem>

<listitem><para>Fix <literal>SIMILAR TO</> for patterns involving
<literal>|</> (Tom)</para></listitem>

<listitem><para>Fix server to use custom DH SSL parameters correctly (Michael
Fuhr)</para></listitem>

<listitem><para>Fix for Bonjour on Intel Macs (Ashley Clark)</para></listitem>

<listitem><para>Fix various minor memory leaks</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-12">
  <title>Release 7.4.12</title>

  <note>
  <title>Release date</title>
  <simpara>2006-02-14</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.11.
  </para>

  <sect2>
   <title>Migration to Version 7.4.12</title>

   <para>
    A dump/restore is not required for those running 7.4.X.  However,
    if you are upgrading from a version earlier than 7.4.11, see the release
    notes for 7.4.11.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>

<listitem><para>Fix potential crash in <command>SET
SESSION AUTHORIZATION</> (CVE-2006-0553)</para>
<para>An unprivileged user could crash the server process, resulting in
momentary denial of service to other users, if the server has been compiled
with Asserts enabled (which is not the default).
Thanks to Akio Ishida for reporting this problem.
</para></listitem>

<listitem><para>Fix bug with row visibility logic in self-inserted
rows (Tom)</para>
<para>Under rare circumstances a row inserted by the current command
could be seen as already valid, when it should not be.  Repairs bug
created in 7.4.9 and 7.3.11 releases.
</para></listitem>

<listitem><para>Fix race condition that could lead to <quote>file already
exists</> errors during pg_clog file creation
(Tom)</para></listitem>

<listitem><para>Properly check <literal>DOMAIN</> constraints for
<literal>UNKNOWN</> parameters in prepared statements
(Neil)</para></listitem>

<listitem><para>Fix to allow restoring dumps that have cross-schema
references to custom operators (Tom)</para></listitem>

<listitem><para>Portability fix for testing presence of <function>finite</>
and <function>isinf</> during configure (Tom)</para></listitem>

</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-11">
  <title>Release 7.4.11</title>

  <note>
  <title>Release date</title>
  <simpara>2006-01-09</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.10.
  </para>

  <sect2>
   <title>Migration to Version 7.4.11</title>

   <para>
    A dump/restore is not required for those running 7.4.X.  However,
    if you are upgrading from a version earlier than 7.4.8, see the release
    notes for 7.4.8.
    Also, you might need to <command>REINDEX</> indexes on textual
    columns after updating, if you are affected by the locale or
    <application>plperl</> issues described below.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>

<listitem><para>Fix for protocol-level Describe messages issued
outside a transaction or in a failed transaction (Tom)</para></listitem>

<listitem><para>Fix character string comparison for locales that consider
different character combinations as equal, such as Hungarian (Tom)</para>
<para>This might require <command>REINDEX</> to fix existing indexes on
textual columns.</para></listitem>

<listitem><para>Set locale environment variables during postmaster startup
to ensure that <application>plperl</> won't change the locale later</para>
<para>This fixes a problem that occurred if the <application>postmaster</> was
started with environment variables specifying a different locale than what
<application>initdb</> had been told.  Under these conditions, any use of
<application>plperl</> was likely to lead to corrupt indexes.  You might need
<command>REINDEX</> to fix existing indexes on
textual columns if this has happened to you.</para></listitem>

<listitem><para>Fix longstanding bug in strpos() and regular expression
handling in certain rarely used Asian multi-byte character sets (Tatsuo)
</para></listitem>

<listitem><para>Fix bug in <filename>/contrib/pgcrypto</> gen_salt,
which caused it not to use all available salt space for MD5 and
XDES algorithms (Marko Kreen, Solar Designer)</para>
<para>Salts for Blowfish and standard DES are unaffected.</para></listitem>

<listitem><para>Fix <filename>/contrib/dblink</> to throw an error,
rather than crashing, when the number of columns specified is different from
what's actually returned by the query (Joe)</para></listitem>

</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-10">
  <title>Release 7.4.10</title>

  <note>
  <title>Release date</title>
  <simpara>2005-12-12</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.9.
  </para>

  <sect2>
   <title>Migration to Version 7.4.10</title>

   <para>
    A dump/restore is not required for those running 7.4.X.  However,
    if you are upgrading from a version earlier than 7.4.8, see the release
    notes for 7.4.8.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>

<listitem><para>Fix race condition in transaction log management</para>
<para>There was a narrow window in which an I/O operation could be initiated
for the wrong page, leading to an Assert failure or data
corruption.</para>
</listitem>

<listitem><para>Prevent failure if client sends Bind protocol message
when current transaction is already aborted</para></listitem>

<listitem><para><filename>/contrib/ltree</> fixes (Teodor)</para></listitem>

<listitem><para>AIX and HPUX compile fixes (Tom)</para></listitem>

<listitem><para>Fix longstanding planning error for outer joins</para>
<para>This bug sometimes caused a bogus error <quote>RIGHT JOIN is
only supported with merge-joinable join conditions</>.</para></listitem>

<listitem><para>Prevent core dump in <application>pg_autovacuum</> when a
table has been dropped</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-9">
  <title>Release 7.4.9</title>

  <note>
  <title>Release date</title>
  <simpara>2005-10-04</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.8.
  </para>

  <sect2>
   <title>Migration to Version 7.4.9</title>

   <para>
    A dump/restore is not required for those running 7.4.X.  However,
    if you are upgrading from a version earlier than 7.4.8, see the release
    notes for 7.4.8.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Fix error that allowed <command>VACUUM</> to remove
<literal>ctid</> chains too soon, and add more checking in code that follows
<literal>ctid</> links</para>
<para>This fixes a long-standing problem that could cause crashes in very rare
circumstances.</para></listitem>
<listitem><para>Fix <type>CHAR()</> to properly pad spaces to the specified
length when using a multiple-byte character set (Yoshiyuki Asaba)</para>
<para>In prior releases, the padding of <type>CHAR()</> was incorrect
because it only padded to the specified number of bytes without
considering how many characters were stored.</para></listitem>
<listitem><para>Fix the sense of the test for read-only transaction
in <command>COPY</></para>
<para>The code formerly prohibited <command>COPY TO</>, where it should
prohibit <command>COPY FROM</>.
</para></listitem>
<listitem><para>Fix planning problem with outer-join ON clauses that reference
only the inner-side relation</para></listitem>
<listitem><para>Further fixes for <literal>x FULL JOIN y ON true</> corner
cases</para></listitem>
<listitem><para>Make <function>array_in</> and <function>array_recv</> more
paranoid about validating their OID parameter</para></listitem>
<listitem><para>Fix missing rows in queries like <literal>UPDATE a=... WHERE
a...</> with GiST index on column <literal>a</></para></listitem>
<listitem><para>Improve robustness of datetime parsing</para></listitem>
<listitem><para>Improve checking for partially-written WAL
pages</para></listitem>
<listitem><para>Improve robustness of signal handling when SSL is
enabled</para></listitem>
<listitem><para>Don't try to open more than <literal>max_files_per_process</>
files during postmaster startup</para></listitem>
<listitem><para>Various memory leakage fixes</para></listitem>
<listitem><para>Various portability improvements</para></listitem>
<listitem><para>Fix PL/PgSQL to handle <literal>var := var</> correctly when
the variable is of pass-by-reference type</para></listitem>
<listitem><para>Update <filename>contrib/tsearch2</> to use current Snowball
code</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-8">
  <title>Release 7.4.8</title>

  <note>
  <title>Release date</title>
  <simpara>2005-05-09</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.7, including several
   security-related issues.
  </para>

  <sect2>
   <title>Migration to Version 7.4.8</title>

   <para>
    A dump/restore is not required for those running 7.4.X.  However,
    it is one possible way of handling two significant security problems
    that have been found in the initial contents of 7.4.X system
    catalogs.  A dump/initdb/reload sequence using 7.4.8's initdb will
    automatically correct these problems.
   </para>

   <para>
    The larger security problem is that the built-in character set encoding
    conversion functions can be invoked from SQL commands by unprivileged
    users, but the functions were not designed for such use and are not
    secure against malicious choices of arguments.  The fix involves changing
    the declared parameter list of these functions so that they can no longer
    be invoked from SQL commands.  (This does not affect their normal use
    by the encoding conversion machinery.)
   </para>

   <para>
    The lesser problem is that the <filename>contrib/tsearch2</> module
    creates several functions that are misdeclared to return
    <type>internal</> when they do not accept <type>internal</> arguments.
    This breaks type safety for all functions using <type>internal</>
    arguments.
   </para>

   <para>
    It is strongly recommended that all installations repair these errors,
    either by initdb or by following the manual repair procedures given
    below.  The errors at least allow unprivileged database users to crash
    their server process, and might allow unprivileged users to gain the
    privileges of a database superuser.
   </para>

   <para>
    If you wish not to do an initdb, perform the following procedures instead.
    As the database superuser, do:

<programlisting>
BEGIN;
UPDATE pg_proc SET proargtypes[3] = 'internal'::regtype
WHERE pronamespace = 11 AND pronargs = 5
     AND proargtypes[2] = 'cstring'::regtype;
-- The command should report having updated 90 rows;
-- if not, rollback and investigate instead of committing!
COMMIT;
</programlisting>

    Next, if you have installed <filename>contrib/tsearch2</>, do:

<programlisting>
BEGIN;
UPDATE pg_proc SET proargtypes[0] = 'internal'::regtype
WHERE oid IN (
   'dex_init(text)'::regprocedure,
   'snb_en_init(text)'::regprocedure,
   'snb_ru_init(text)'::regprocedure,
   'spell_init(text)'::regprocedure,
   'syn_init(text)'::regprocedure
);
-- The command should report having updated 5 rows;
-- if not, rollback and investigate instead of committing!
COMMIT;
</programlisting>

    If this command fails with a message like <quote>function
    "dex_init(text)" does not exist</>, then either <filename>tsearch2</>
    is not installed in this database, or you already did the update.
   </para>

   <para>
    The above procedures must be carried out in <emphasis>each</> database
    of an installation, including <literal>template1</>, and ideally
    including <literal>template0</> as well.  If you do not fix the
    template databases then any subsequently created databases will contain
    the same errors.  <literal>template1</> can be fixed in the same way
    as any other database, but fixing <literal>template0</> requires
    additional steps.  First, from any database issue:
<programlisting>
UPDATE pg_database SET datallowconn = true WHERE datname = 'template0';
</programlisting>
     Next connect to <literal>template0</> and perform the above repair
     procedures.  Finally, do:
<programlisting>
-- re-freeze template0:
VACUUM FREEZE;
-- and protect it against future alterations:
UPDATE pg_database SET datallowconn = false WHERE datname = 'template0';
</programlisting>
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Change encoding function signature to prevent
misuse</para></listitem>
<listitem><para>Change <filename>contrib/tsearch2</> to avoid unsafe use of
<type>INTERNAL</> function results</para></listitem>
<listitem><para>Repair ancient race condition that allowed a transaction to be
seen as committed for some purposes (eg SELECT FOR UPDATE) slightly sooner
than for other purposes</para>
<para>This is an extremely serious bug since it could lead to apparent
data inconsistencies being briefly visible to applications.</para></listitem>
<listitem><para>Repair race condition between relation extension and
VACUUM</para>
<para>This could theoretically have caused loss of a page's worth of
freshly-inserted data, although the scenario seems of very low probability.
There are no known cases of it having caused more than an Assert failure.
</para></listitem>
<listitem><para>Fix comparisons of <type>TIME WITH TIME ZONE</> values</para>
<para>
The comparison code was wrong in the case where the
<literal>--enable-integer-datetimes</> configuration switch had been used.
NOTE: if you have an index on a <type>TIME WITH TIME ZONE</> column,
it will need to be <command>REINDEX</>ed after installing this update, because
the fix corrects the sort order of column values.
</para></listitem>
<listitem><para>Fix <function>EXTRACT(EPOCH)</> for
<type>TIME WITH TIME ZONE</> values</para></listitem>
<listitem><para>Fix mis-display of negative fractional seconds in
<type>INTERVAL</> values</para>
<para>
This error only occurred when the
<literal>--enable-integer-datetimes</> configuration switch had been used.
</para></listitem>
<listitem><para>Ensure operations done during backend shutdown are counted by
statistics collector</para>
<para>
This is expected to resolve reports of <application>pg_autovacuum</>
not vacuuming the system catalogs often enough &mdash; it was not being
told about catalog deletions caused by temporary table removal during
backend exit.
</para></listitem>
<listitem><para>Additional buffer overrun checks in plpgsql
(Neil)</para></listitem>
<listitem><para>Fix pg_dump to dump trigger names containing <literal>%</>
correctly (Neil)</para></listitem>
<listitem><para>Fix <filename>contrib/pgcrypto</> for newer OpenSSL builds
(Marko Kreen)</para></listitem>
<listitem><para>Still more 64-bit fixes for
<filename>contrib/intagg</></para></listitem>
<listitem><para>Prevent incorrect optimization of functions returning
<type>RECORD</></para></listitem>
<listitem><para>Prevent <function>to_char(interval)</> from dumping core for
month-related formats</para></listitem>
<listitem><para>Prevent crash on <literal>COALESCE(NULL,NULL)</></para></listitem>
<listitem><para>Fix <function>array_map</> to call PL functions correctly</para></listitem>
<listitem><para>Fix permission checking in <command>ALTER DATABASE RENAME</></para></listitem>
<listitem><para>Fix <command>ALTER LANGUAGE RENAME</></para></listitem>
<listitem><para>Make <function>RemoveFromWaitQueue</> clean up after itself</para>
<para>
This fixes a lock management error that would only be visible if a transaction
was kicked out of a wait for a lock (typically by query cancel) and then the
holder of the lock released it within a very narrow window.
</para></listitem>
<listitem><para>Fix problem with untyped parameter appearing in
<command>INSERT ... SELECT</></para></listitem>
<listitem><para>Fix <command>CLUSTER</> failure after
<command>ALTER TABLE SET WITHOUT OIDS</></para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-7">
  <title>Release 7.4.7</title>

  <note>
  <title>Release date</title>
  <simpara>2005-01-31</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.6, including several
   security-related issues.
  </para>

  <sect2>
   <title>Migration to Version 7.4.7</title>

   <para>
    A dump/restore is not required for those running 7.4.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Disallow <command>LOAD</> to non-superusers</para>
<para>
On platforms that will automatically execute initialization functions of a
shared library (this includes at least Windows and ELF-based Unixen),
<command>LOAD</> can be used to make the server execute arbitrary code.
Thanks to NGS Software for reporting this.</para></listitem>
<listitem><para>Check that creator of an aggregate function has the right to
execute the specified transition functions</para>
<para>
This oversight made it possible to bypass denial of EXECUTE
permission on a function.</para></listitem>
<listitem><para>Fix security and 64-bit issues in
contrib/intagg</para></listitem>
<listitem><para>Add needed STRICT marking to some contrib functions (Kris
Jurka)</para></listitem>
<listitem><para>Avoid buffer overrun when plpgsql cursor declaration has too
many parameters (Neil)</para></listitem>
<listitem><para>Fix planning error for FULL and RIGHT outer joins</para>
<para>
The result of the join was mistakenly supposed to be sorted the same as the
left input.  This could not only deliver mis-sorted output to the user, but
in case of nested merge joins could give outright wrong answers.
</para></listitem>
<listitem><para>Fix plperl for quote marks in tuple fields</para></listitem>
<listitem><para>Fix display of negative intervals in SQL and GERMAN
datestyles</para></listitem>
<listitem><para>Make age(timestamptz) do calculation in local timezone not
GMT</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-6">
  <title>Release 7.4.6</title>

  <note>
  <title>Release date</title>
  <simpara>2004-10-22</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.5.
  </para>


  <sect2>
   <title>Migration to Version 7.4.6</title>

   <para>
    A dump/restore is not required for those running 7.4.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Repair possible failure to update hint bits on disk</para>
<para>
Under rare circumstances this oversight could lead to
<quote>could not access transaction status</> failures, which qualifies
it as a potential-data-loss bug.
</para></listitem>
<listitem><para>Ensure that hashed outer join does not miss tuples</para>
<para>
Very large left joins using a hash join plan could fail to output unmatched
left-side rows given just the right data distribution.
</para></listitem>
<listitem><para>Disallow running <application>pg_ctl</> as root</para>
<para>
This is to guard against any possible security issues.
</para></listitem>
<listitem><para>Avoid using temp files in <filename>/tmp</> in <command>make_oidjoins_check</command></para>
<para>
This has been reported as a security issue, though it's hardly worthy of
concern since there is no reason for non-developers to use this script anyway.
</para></listitem>
<listitem><para>Prevent forced backend shutdown from re-emitting prior command
result</para>
<para>
In rare cases, a client might think that its last command had succeeded when
it really had been aborted by forced database shutdown.
</para></listitem>
<listitem><para>Repair bug in <function>pg_stat_get_backend_idset</function></para>
<para>
This could lead to misbehavior in some of the system-statistics views.
</para></listitem>
<listitem><para>Fix small memory leak in postmaster</para></listitem>
<listitem><para>Fix <quote>expected both swapped tables to have TOAST
tables</> bug</para>
<para>
This could arise in cases such as CLUSTER after ALTER TABLE DROP COLUMN.
</para></listitem>
<listitem><para>Prevent <literal>pg_ctl restart</> from adding <literal>-D</> multiple times</para></listitem>
<listitem><para>Fix problem with NULL values in GiST indexes</para></listitem>
<listitem><para><literal>::</> is no longer interpreted as a variable in an
ECPG prepare statement</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-5">
  <title>Release 7.4.5</title>

  <note>
  <title>Release date</title>
  <simpara>2004-08-18</simpara>
  </note>

  <para>
   This release contains one serious bug fix over 7.4.4.
  </para>


  <sect2>
   <title>Migration to Version 7.4.5</title>

   <para>
    A dump/restore is not required for those running 7.4.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Repair possible crash during concurrent B-tree index insertions</para>
<para>
This patch fixes a rare case in which concurrent insertions into a B-tree index
could result in a server panic.  No permanent damage would result, but it's
still worth a re-release.  The bug does not exist in pre-7.4 releases.
</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-4">
  <title>Release 7.4.4</title>

  <note>
  <title>Release date</title>
  <simpara>2004-08-16</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.3.
  </para>


  <sect2>
   <title>Migration to Version 7.4.4</title>

   <para>
    A dump/restore is not required for those running 7.4.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Prevent possible loss of committed transactions during crash</para>
<para>
Due to insufficient interlocking between transaction commit and checkpointing,
it was possible for transactions committed just before the most recent
checkpoint to be lost, in whole or in part, following a database crash and
restart.  This is a serious bug that has existed
since <productname>PostgreSQL</productname> 7.1.
</para></listitem>
<listitem><para>Check HAVING restriction before evaluating result list of an
aggregate plan</para></listitem>
<listitem><para>Avoid crash when session's current user ID is deleted</para></listitem>
<listitem><para>Fix hashed crosstab for zero-rows case (Joe)</para></listitem>
<listitem><para>Force cache update after renaming a column in a foreign key</para></listitem>
<listitem><para>Pretty-print UNION queries correctly</para></listitem>
<listitem><para>Make psql handle <literal>\r\n</> newlines properly in COPY IN</para></listitem>
<listitem><para><application>pg_dump</> handled ACLs with grant options incorrectly</para></listitem>
<listitem><para>Fix thread support for OS X and Solaris</para></listitem>
<listitem><para>Updated JDBC driver (build 215) with various fixes</para></listitem>
<listitem><para>ECPG fixes</para></listitem>
<listitem><para>Translation updates (various contributors)</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-3">
  <title>Release 7.4.3</title>

  <note>
  <title>Release date</title>
  <simpara>2004-06-14</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.2.
  </para>


  <sect2>
   <title>Migration to Version 7.4.3</title>

   <para>
    A dump/restore is not required for those running 7.4.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Fix temporary memory leak when using non-hashed aggregates (Tom)</para></listitem>
<listitem><para>ECPG fixes, including some for Informix compatibility (Michael)</para></listitem>
<listitem><para>Fixes for compiling with thread-safety, particularly Solaris (Bruce)</para></listitem>
<listitem><para>Fix error in COPY IN termination when using the old network protocol (ljb)</para></listitem>
<listitem><para>Several important fixes in pg_autovacuum, including fixes for
large tables, unsigned oids, stability, temp tables, and debug mode
(Matthew T. O'Connor)</para></listitem>
<listitem><para>Fix problem with reading tar-format dumps on NetBSD and BSD/OS (Bruce)</para></listitem>
<listitem><para>Several JDBC fixes</para></listitem>
<listitem><para>Fix ALTER SEQUENCE RESTART where last_value equals the restart value (Tom)</para></listitem>
<listitem><para>Repair failure to recalculate nested sub-selects (Tom)</para></listitem>
<listitem><para>Fix problems with non-constant expressions in LIMIT/OFFSET</para></listitem>
<listitem><para>Support FULL JOIN with no join clause, such as X FULL JOIN Y ON TRUE (Tom)</para></listitem>
<listitem><para>Fix another zero-column table bug (Tom)</para></listitem>
<listitem><para>Improve handling of non-qualified identifiers in GROUP BY clauses in sub-selects (Tom)</para>
<para>
Select-list aliases within the sub-select will now take precedence over
names from outer query levels.
</para></listitem>
<listitem><para>Do not generate <quote>NATURAL CROSS JOIN</> when decompiling rules (Tom)</para></listitem>
<listitem><para>Add checks for invalid field length in binary COPY (Tom)</para>
<para>
 This fixes a difficult-to-exploit security hole.
</para></listitem>
<listitem><para>Avoid locking conflict between <command>ANALYZE</command> and <command>LISTEN</command>/<command>NOTIFY</command></para></listitem>
<listitem><para>Numerous translation updates (various contributors)</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-2">
  <title>Release 7.4.2</title>

  <note>
  <title>Release date</title>
  <simpara>2004-03-08</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.1.
  </para>


  <sect2>
   <title>Migration to Version 7.4.2</title>

   <para>
    A dump/restore is not required for those running 7.4.X.  However,
    it might be advisable as the easiest method of incorporating fixes for
    two errors that have been found in the initial contents of 7.4.X system
    catalogs.  A dump/initdb/reload sequence using 7.4.2's initdb will
    automatically correct these problems.
   </para>

   <para>
    The more severe of the two errors is that data type <type>anyarray</>
    has the wrong alignment label; this is a problem because the
    <structname>pg_statistic</> system catalog uses <type>anyarray</>
    columns.  The mislabeling can cause planner misestimations and even
    crashes when planning queries that involve <literal>WHERE</> clauses on
    double-aligned columns (such as <type>float8</> and <type>timestamp</>).
    It is strongly recommended that all installations repair this error,
    either by initdb or by following the manual repair procedure given
    below.
   </para>

   <para>
    The lesser error is that the system view <structname>pg_settings</>
    ought to be marked as having public update access, to allow
    <literal>UPDATE pg_settings</> to be used as a substitute for
    <command>SET</>.  This can also be fixed either by initdb or manually,
    but it is not necessary to fix unless you want to use <literal>UPDATE
    pg_settings</>.
   </para>

   <para>
    If you wish not to do an initdb, the following procedure will work
    for fixing <structname>pg_statistic</>.  As the database superuser,
    do:

<programlisting>
-- clear out old data in pg_statistic:
DELETE FROM pg_statistic;
VACUUM pg_statistic;
-- this should update 1 row:
UPDATE pg_type SET typalign = 'd' WHERE oid = 2277;
-- this should update 6 rows:
UPDATE pg_attribute SET attalign = 'd' WHERE atttypid = 2277;
--
-- At this point you MUST start a fresh backend to avoid a crash!
--
-- repopulate pg_statistic:
ANALYZE;
</programlisting>

    This can be done in a live database, but beware that all backends
    running in the altered database must be restarted before it is safe to
    repopulate <structname>pg_statistic</>.
   </para>

   <para>
    To repair the <structname>pg_settings</> error, simply do:
<programlisting>
GRANT SELECT, UPDATE ON pg_settings TO PUBLIC;
</programlisting>
   </para>

   <para>
    The above procedures must be carried out in <emphasis>each</> database
    of an installation, including <literal>template1</>, and ideally
    including <literal>template0</> as well.  If you do not fix the
    template databases then any subsequently created databases will contain
    the same errors.  <literal>template1</> can be fixed in the same way
    as any other database, but fixing <literal>template0</> requires
    additional steps.  First, from any database issue:
<programlisting>
UPDATE pg_database SET datallowconn = true WHERE datname = 'template0';
</programlisting>
     Next connect to <literal>template0</> and perform the above repair
     procedures.  Finally, do:
<programlisting>
-- re-freeze template0:
VACUUM FREEZE;
-- and protect it against future alterations:
UPDATE pg_database SET datallowconn = false WHERE datname = 'template0';
</programlisting>
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<para>
   Release 7.4.2 incorporates all the fixes included in release 7.3.6,
   plus the following fixes:
</para>

<itemizedlist>
<listitem><para>Fix <structname>pg_statistics</> alignment bug that could crash optimizer</para>
<para>See above for details about this problem.</para></listitem>
<listitem><para>Allow non-super users to update <structname>pg_settings</></para></listitem>
<listitem><para>Fix several optimizer bugs, most of which led to
<quote>variable not found in subplan target lists</> errors</para></listitem>
<listitem><para>Avoid out-of-memory failure during startup of large multiple
index scan</para></listitem>
<listitem><para>Fix multibyte problem that could lead to <quote>out of
memory</> error during <command>COPY IN</></para></listitem>
<listitem><para>Fix problems with <command>SELECT INTO</> / <command>CREATE
TABLE AS</> from tables without OIDs</para></listitem>
<listitem><para>Fix problems with <filename>alter_table</> regression test
during parallel testing</para></listitem>
<listitem><para>Fix problems with hitting open file limit, especially on OS X (Tom)</para></listitem>
<listitem><para>Partial fix for Turkish-locale issues</para>
<para>initdb will succeed now in Turkish locale, but there are still some
inconveniences associated with the <literal>i/I</> problem.</para></listitem>
<listitem><para>Make pg_dump set client encoding on restore</para></listitem>
<listitem><para>Other minor pg_dump fixes</para></listitem>
<listitem><para>Allow ecpg to again use C keywords as column names (Michael)</para></listitem>
<listitem><para>Added ecpg <literal>WHENEVER NOT_FOUND</> to
<literal>SELECT/INSERT/UPDATE/DELETE</> (Michael)</para></listitem>
<listitem><para>Fix ecpg crash for queries calling set-returning functions (Michael)</para></listitem>
<listitem><para>Various other ecpg fixes (Michael)</para></listitem>
<listitem><para>Fixes for Borland compiler</para></listitem>
<listitem><para>Thread build improvements (Bruce)</para></listitem>
<listitem><para>Various other build fixes</para></listitem>
<listitem><para>Various JDBC fixes</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-4-1">
  <title>Release 7.4.1</title>

  <note>
  <title>Release date</title>
  <simpara>2003-12-22</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.4.
  </para>


  <sect2>
   <title>Migration to Version 7.4.1</title>

   <para>
    A dump/restore is <emphasis>not</emphasis> required for those
    running 7.4.
   </para>

   <para>
    If you want to install the fixes in the information schema
    you need to reload it into the database.
    This is either accomplished by initializing a new cluster
    by running <command>initdb</command>, or by running the following
    sequence of SQL commands in each database (ideally including
    <literal>template1</literal>) as a superuser in
    <application>psql</application>, after installing the new release:
<programlisting>
DROP SCHEMA information_schema CASCADE;
\i /usr/local/pgsql/share/information_schema.sql
</programlisting>
    Substitute your installation path in the second command.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Fixed bug in <command>CREATE SCHEMA</command> parsing in ECPG (Michael)</para></listitem>
<listitem><para>Fix compile error when <option>--enable-thread-safety</option> and <option>--with-perl</option> are used together (Peter)</para></listitem>
<listitem><para>Fix for subqueries that used hash joins (Tom)</para>
<para>
   Certain subqueries that used hash joins would crash because of
   improperly shared structures.
</para></listitem>
<listitem><para>Fix free space map compaction bug (Tom)</para>
<para>
   This fixes a bug where compaction of the free space map could lead
   to a database server shutdown.
</para>
</listitem>
<listitem><para>Fix for Borland compiler build of libpq (Bruce)</para></listitem>
<listitem><para>Fix <function>netmask()</function> and <function>hostmask()</function> to return the maximum-length masklen (Tom)</para>
<para>
   Fix these functions to return values consistent with pre-7.4
   releases.
</para>
</listitem>
<listitem><para>Several <filename>contrib/pg_autovacuum</filename> fixes</para>
<para>
   Fixes include improper variable initialization, missing vacuum after
   <command>TRUNCATE</command>, and duration computation overflow for long vacuums.
</para>
</listitem>
<listitem><para>Allow compile of <filename>contrib/cube</filename> under Cygwin (Jason Tishler)</para></listitem>
<listitem><para>Fix Solaris use of password file when no passwords are defined (Tom)</para>
<para>
   Fix crash on Solaris caused by use of any type of password
   authentication when no passwords were defined.
</para>
</listitem>
<listitem><para>JDBC fix for thread problems, other fixes</para></listitem>
<listitem><para>Fix for <type>bytea</type> index lookups (Joe)</para></listitem>
<listitem><para>Fix information schema for bit data types (Peter)</para></listitem>
<listitem><para>Force zero_damaged_pages to be on during recovery from WAL</para></listitem>
<listitem><para>Prevent some obscure cases of <quote>variable not in subplan target lists</quote></para></listitem>
<listitem><para>Make <function>PQescapeBytea</function> and <function>byteaout</function> consistent with each other (Joe)</para></listitem>
<listitem><para>Escape <type>bytea</type> output for bytes &gt; 0x7e(Joe)</para>
<para>
 If different client encodings are used for <type>bytea</type> output and input, it
 is possible for <type>bytea</type> values to be corrupted by the differing
 encodings.  This fix escapes all bytes that might be affected.
</para>
</listitem>
<listitem><para>Added missing <function>SPI_finish()</function> calls to dblink's <function>get_tuple_of_interest()</function> (Joe)</para></listitem>
<listitem><para>New Czech FAQ</para></listitem>
<listitem><para>Fix information schema view <literal>constraint_column_usage</literal> for foreign keys (Peter)</para></listitem>
<listitem><para>ECPG fixes (Michael)</para></listitem>
<listitem><para>Fix bug with multiple <literal>IN</literal> subqueries and joins in the subqueries (Tom)</para></listitem>
<listitem><para>Allow <literal>COUNT('x')</literal> to work (Tom)</para></listitem>
<listitem><para>Install ECPG include files for Informix compatibility into separate directory (Peter)</para>
<para>
 Some names of ECPG include files for Informix compatibility conflicted with operating system include files.
 By installing them in their own directory, name conflicts have been reduced.
</para>
</listitem>
<listitem><para>Fix SSL memory leak (Neil)</para>
<para>
 This release fixes a bug in 7.4 where SSL didn't free all memory it allocated.
</para>
</listitem>
<listitem><para>Prevent <filename>pg_service.conf</filename> from using service name as default dbname (Bruce)</para></listitem>
<listitem><para>Fix local ident authentication on FreeBSD (Tom)</para></listitem>
</itemizedlist>

 </sect2>
</sect1>

<sect1 id="release-7-4">
 <title>Release 7.4</title>

 <note>
  <title>Release date</title>
  <simpara>2003-11-17</simpara>
 </note>

 <sect2>
  <title>Overview</title>

  <para>
   Major changes in this release:
  </para>

  <variablelist>
   <varlistentry>
    <term>
     <literal>IN</literal> / <literal>NOT IN</literal> subqueries are
     now much more efficient
    </term>

    <listitem>
     <para>
      In previous releases, <literal>IN</literal>/<literal>NOT
      IN</literal> subqueries were joined to the upper query by
      sequentially scanning the subquery looking for a match.  The
      7.4 code uses the same sophisticated techniques used by
      ordinary joins and so is much faster.  An
      <literal>IN</literal> will now usually be as fast as or faster
      than an equivalent <literal>EXISTS</literal> subquery; this
      reverses the conventional wisdom that applied to previous
      releases.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     Improved <literal>GROUP BY</literal> processing by using hash buckets
    </term>

    <listitem>
     <para>
      In previous releases, rows to be grouped had to be sorted
      first.  The 7.4 code can do <literal>GROUP BY</literal>
      without sorting, by accumulating results into a hash table
      with one entry per group.  It will still use the sort
      technique, however, if the hash table is estimated to be too
      large to fit in <varname>sort_mem</>.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     New multikey hash join capability
    </term>

    <listitem>
     <para>
      In previous releases, hash joins could only occur on single
      keys.  This release allows multicolumn hash joins.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     Queries using the explicit <literal>JOIN</literal> syntax are
     now better optimized
    </term>

    <listitem>
     <para>
      Prior releases evaluated queries using the explicit
      <literal>JOIN</literal> syntax only in the order implied by
      the syntax. 7.4 allows full optimization of these queries,
      meaning the optimizer considers all possible join orderings
      and chooses the most efficient.  Outer joins, however, must
      still follow the declared ordering.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     Faster and more powerful regular expression code
    </term>

    <listitem>
     <para>
      The entire regular expression module has been replaced with a
      new version by Henry Spencer, originally written for Tcl.  The
      code greatly improves performance and supports several flavors
      of regular expressions.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     Function-inlining for simple SQL functions
    </term>

    <listitem>
     <para>
      Simple SQL functions can now be inlined by including their SQL
      in the main query.  This improves performance by eliminating
      per-call overhead.  That means simple SQL functions now
      behave like macros.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     Full support for IPv6 connections and IPv6 address data types
    </term>

    <listitem>
     <para>
      Previous releases allowed only IPv4 connections, and the IP
      data types only supported IPv4 addresses. This release adds
      full IPv6 support in both of these areas.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     Major improvements in SSL performance and reliability
    </term>

    <listitem>
     <para>
      Several people very familiar with the SSL API have overhauled
      our SSL code to improve SSL key negotiation and error
      recovery.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     Make free space map efficiently reuse empty index pages,
     and other free space management improvements
    </term>

    <listitem>
     <para>
      In previous releases, B-tree index pages that were left empty
      because of deleted rows could only be reused by rows with
      index values similar to the rows originally indexed on that
      page. In 7.4, <command>VACUUM</command> records empty index
      pages and allows them to be reused for any future index rows.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     SQL-standard information schema
    </term>

    <listitem>
     <para>
      The information schema provides a standardized and stable way
      to access information about the schema objects defined in a
      database.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     Cursors conform more closely to the SQL standard
    </term>

    <listitem>
     <para>
      The commands <command>FETCH</command> and
      <command>MOVE</command> have been overhauled to conform more
      closely to the SQL standard.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     Cursors can exist outside transactions
    </term>

    <listitem>
     <para>
      These cursors are also called holdable cursors.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     New client-to-server protocol
    </term>

    <listitem>
     <para>
      The new protocol adds error codes, more status information,
      faster startup, better support for binary data transmission,
      parameter values separated from SQL commands, prepared
      statements available at the protocol level, and cleaner
      recovery from <command>COPY</command> failures.  The older
      protocol is still supported by both server and clients.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     <application>libpq</application> and
     <application>ECPG</application> applications are now fully
     thread-safe
    </term>

    <listitem>
     <para>
      While previous <application>libpq</application> releases
      already supported threads, this release improves thread safety
      by fixing some non-thread-safe code that was used during
      database connection startup.  The <command>configure</command>
      option <option>--enable-thread-safety</option> must be used to
      enable this feature.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     New version of full-text indexing
    </term>

    <listitem>
     <para>
      A new full-text indexing suite is available in
      <filename>contrib/tsearch2</filename>.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     New autovacuum tool
    </term>

    <listitem>
     <para>
      The new autovacuum tool in
      <filename>contrib/autovacuum</filename> monitors the database
      statistics tables for
      <command>INSERT</command>/<command>UPDATE</command>/<command>DELETE</command>
      activity and automatically vacuums tables when needed.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     Array handling has been improved and moved into the server core
    </term>

    <listitem>
     <para>
      Many array limitations have been removed, and arrays behave
      more like fully-supported data types.
     </para>
    </listitem>
   </varlistentry>

  </variablelist>
 </sect2>

 <sect2>
  <title>Migration to Version 7.4</title>

  <para>
   A dump/restore using <application>pg_dump</application> is
   required for those wishing to migrate data from any previous
   release.
  </para>

  <para>
   Observe the following incompatibilities:
  </para>

  <itemizedlist>
   <listitem>
    <para>
     The server-side autocommit setting was removed and
     reimplemented in client applications and languages.
     Server-side autocommit was causing too many problems with
     languages and applications that wanted to control their own
     autocommit behavior, so autocommit was removed from the server
     and added to individual client APIs as appropriate.
    </para>
   </listitem>

   <listitem>
    <para>
     Error message wording has changed substantially in this
     release.  Significant effort was invested to make the messages
     more consistent and user-oriented.  If your applications try to
     detect different error conditions by parsing the error message,
     you are strongly encouraged to use the new error code facility instead.
    </para>
   </listitem>

   <listitem>
    <para>
     Inner joins using the explicit <literal>JOIN</literal> syntax
     might behave differently because they are now better
     optimized.
    </para>
   </listitem>

   <listitem>
    <para>
     A number of server configuration parameters have been renamed
     for clarity, primarily those related to
     logging.
    </para>
   </listitem>

   <listitem>
    <para>
     <literal>FETCH 0</literal> or <literal>MOVE 0</literal> now
     does nothing.  In prior releases, <literal>FETCH 0</literal>
     would fetch all remaining rows, and <literal>MOVE 0</literal>
     would move to the end of the cursor.
    </para>
   </listitem>

   <listitem>
    <para>
     <command>FETCH</command> and <command>MOVE</command> now return
     the actual number of rows fetched/moved, or zero if at the
     beginning/end of the cursor.  Prior releases would return the
     row count passed to the command, not the number of rows
     actually fetched or moved.
    </para>
   </listitem>

   <listitem>
    <para>
     <command>COPY</command> now can process files that use
     carriage-return or carriage-return/line-feed end-of-line
     sequences. Literal carriage-returns and line-feeds are no
     longer accepted in data values; use <literal>\r</literal> and
     <literal>\n</literal> instead.
    </para>
   </listitem>

   <listitem>
    <para>
     Trailing spaces are now trimmed when converting from type
     <type>char(<replaceable>n</>)</type> to
     <type>varchar(<replaceable>n</>)</type> or <type>text</type>.
     This is what most people always expected to happen anyway.
    </para>
   </listitem>

   <listitem>
    <para>
     The data type <type>float(<replaceable>p</>)</type> now
     measures <replaceable>p</> in binary digits, not decimal
     digits.  The new behavior follows the SQL standard.
    </para>
   </listitem>

   <listitem>
    <para>
     Ambiguous date values now must match the ordering specified by
     the <varname>datestyle</varname> setting.  In prior releases, a
     date specification of <literal>10/20/03</> was interpreted as a
     date in October even if <varname>datestyle</> specified that
     the day should be first.  7.4 will throw an error if a date
     specification is invalid for the current setting of
     <varname>datestyle</>.
    </para>
   </listitem>

   <listitem>
    <para>
     The functions <function>oidrand</function>,
     <function>oidsrand</function>, and
     <function>userfntest</function> have been removed.  These
     functions were determined to be no longer useful.
    </para>
   </listitem>

   <listitem>
    <para>
     String literals specifying time-varying date/time values, such
     as <literal>'now'</literal> or <literal>'today'</literal> will
     no longer work as expected in column default expressions; they
     now cause the time of the table creation to be the default, not
     the time of the insertion.  Functions such as
     <function>now()</>, <function>current_timestamp</>, or
     <function>current_date</function> should be used instead.
    </para>

    <para>
     In previous releases, there was special code so that strings
     such as <literal>'now'</literal> were interpreted at
     <command>INSERT</> time and not at table creation time, but
     this work around didn't cover all cases.  Release 7.4 now
     requires that defaults be defined properly using functions such
     as <function>now()</> or <function>current_timestamp</>. These
     will work in all situations.
    </para>
   </listitem>

   <listitem>
    <para>
     The dollar sign (<literal>$</>) is no longer allowed in
     operator names.  It can instead be a non-first character in
     identifiers.  This was done to improve compatibility with other
     database systems, and to avoid syntax problems when parameter
     placeholders (<literal>$<replaceable>n</></>) are written
     adjacent to operators.
    </para>
   </listitem>

  </itemizedlist>
 </sect2>

 <sect2>
  <title>Changes</title>

  <para>
   Below you will find a detailed account of the changes between
   release 7.4 and the previous major release.
  </para>

 <sect3>
  <title>Server Operation Changes</title>

  <itemizedlist>
   <listitem>
    <para>
     Allow IPv6 server connections (Nigel Kukard, Johan Jordaan,
     Bruce, Tom, Kurt Roeckx, Andrew Dunstan)
    </para>
   </listitem>

   <listitem>
    <para>
     Fix SSL to handle errors cleanly (Nathan Mueller)
    </para>
    <para>
     In prior releases, certain SSL API error reports were not
     handled correctly.  This release fixes those problems.
    </para>
   </listitem>

   <listitem>
    <para>
     SSL protocol security and performance improvements (Sean Chittenden)
    </para>
    <para>
     SSL key renegotiation was happening too frequently, causing poor
     SSL performance.  Also, initial key handling was improved.
    </para>
   </listitem>

   <listitem>
    <para>
     Print lock information when a deadlock is detected (Tom)
    </para>
    <para>
     This allows easier debugging of deadlock situations.
    </para>
   </listitem>

   <listitem>
    <para>
     Update <filename>/tmp</filename> socket modification times
     regularly to avoid their removal (Tom)
    </para>
    <para>
     This should help prevent <filename>/tmp</filename> directory
     cleaner administration scripts from removing server socket
     files.
    </para>
   </listitem>

   <listitem><para>Enable PAM for Mac OS X (Aaron Hillegass)</para></listitem>

   <listitem>
    <para>Make B-tree indexes fully WAL-safe (Tom)</para>
    <para>
     In prior releases, under certain rare cases, a server crash
     could cause B-tree indexes to become corrupt. This release
     removes those last few rare cases.
    </para>
   </listitem>

   <listitem><para>Allow B-tree index compaction and empty page reuse (Tom)</para></listitem>

   <listitem>
    <para>
     Fix inconsistent index lookups during split of first root page (Tom)
    </para>
    <para>
     In prior releases, when a single-page index split into two
     pages, there was a brief period when another database session
     could miss seeing an index entry.  This release fixes that rare
     failure case.
    </para>
   </listitem>

   <listitem><para>Improve free space map allocation logic (Tom)</para></listitem>

   <listitem>
    <para>Preserve free space information between server restarts (Tom)</para>
    <para>
     In prior releases, the free space map was not saved when the
     postmaster was stopped, so newly started servers had no free
     space information. This release saves the free space map, and
     reloads it when the server is restarted.
    </para>
   </listitem>

   <listitem><para>Add start time to <literal>pg_stat_activity</literal> (Neil)</para></listitem>
   <listitem><para>New code to detect corrupt disk pages; erase with <varname>zero_damaged_pages</varname> (Tom)</para></listitem>
   <listitem><para>New client/server protocol: faster, no username length limit, allow clean exit from <command>COPY</command> (Tom)</para></listitem>
   <listitem><para>Add transaction status, table ID, column ID to client/server protocol (Tom)</para></listitem>
   <listitem><para>Add binary I/O to client/server protocol (Tom)</para></listitem>
   <listitem><para>Remove autocommit server setting; move to client applications (Tom)</para></listitem>
   <listitem><para>New error message wording, error codes, and three levels of error detail (Tom, Joe, Peter)</para></listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>Performance Improvements</title>

  <itemizedlist>
   <listitem><para>Add hashing for <literal>GROUP BY</literal> aggregates (Tom)</para></listitem>
   <listitem><para>Make nested-loop joins be smarter about multicolumn indexes (Tom)</para></listitem>
   <listitem><para>Allow multikey hash joins (Tom)</para></listitem>
   <listitem><para>Improve constant folding (Tom)</para></listitem>
   <listitem><para>Add ability to inline simple SQL functions (Tom)</para></listitem>

   <listitem>
    <para>Reduce memory usage for queries using complex functions (Tom)</para>
    <para>
     In prior releases, functions returning allocated memory would
     not free it until the query completed. This release allows the
     freeing of function-allocated memory when the function call
     completes, reducing the total memory used by functions.
    </para>
   </listitem>

   <listitem>
    <para>Improve GEQO optimizer performance (Tom)</para>
    <para>
     This release fixes several inefficiencies in the way the GEQO optimizer
     manages potential query paths.
    </para>
   </listitem>

   <listitem>
    <para>
     Allow <literal>IN</>/<literal>NOT IN</> to be handled via hash
     tables (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Improve <literal>NOT IN (<replaceable>subquery</>)</literal>
     performance (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Allow most <literal>IN</literal> subqueries to be processed as
     joins (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Pattern matching operations can use indexes regardless of
     locale (Peter)
    </para>
    <para>
     There is no way for non-ASCII locales to use the standard
     indexes for <literal>LIKE</literal> comparisons. This release
     adds a way to create a special index for
     <literal>LIKE</literal>.
    </para>
   </listitem>

   <listitem>
    <para>Allow the postmaster to preload libraries using <varname>preload_libraries</varname> (Joe)</para>
    <para>
     For shared libraries that require a long time to load, this
     option is available so the library can be preloaded in the
     postmaster and inherited by all database sessions.
    </para>
   </listitem>

   <listitem>
    <para>
     Improve optimizer cost computations, particularly for subqueries (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Avoid sort when subquery <literal>ORDER BY</literal> matches upper query (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Deduce that <literal>WHERE a.x = b.y AND b.y = 42</literal> also
     means <literal>a.x = 42</literal> (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Allow hash/merge joins on complex joins (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Allow hash joins for more data types (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Allow join optimization of explicit inner joins, disable with
     <varname>join_collapse_limit</varname> (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Add parameter <varname>from_collapse_limit</varname> to control
     conversion of subqueries to joins (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Use faster and more powerful regular expression code from Tcl
     (Henry Spencer, Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Use bit-mapped relation sets in the optimizer (Tom)
    </para>
   </listitem>

   <listitem>
    <para>Improve connection startup time (Tom)</para>
    <para>
     The new client/server protocol requires fewer network packets to
     start a database session.
    </para>
   </listitem>

   <listitem>
    <para>
     Improve trigger/constraint performance (Stephan)
    </para>
   </listitem>

   <listitem>
    <para>
     Improve speed of <literal>col IN (const, const, const, ...)</literal> (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Fix hash indexes which were broken in rare cases (Tom)
    </para>
   </listitem>

   <listitem><para>Improve hash index concurrency and speed (Tom)</para>
    <para>
     Prior releases suffered from poor hash index performance,
     particularly for high concurrency situations. This release fixes
     that, and the development group is interested in reports
     comparing B-tree and hash index performance.
    </para>
   </listitem>

   <listitem>
    <para>Align shared buffers on 32-byte boundary for copy speed improvement (Manfred Spraul)</para>
    <para>
     Certain CPU's perform faster data copies when addresses are
     32-byte aligned.
    </para>
   </listitem>

   <listitem>
    <para>Data type <type>numeric</type> reimplemented for better performance (Tom)</para>
    <para>
     <type>numeric</type> used to be stored in base 100. The new code
     uses base 10000, for significantly better performance.
    </para>
   </listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>Server Configuration Changes</title>

  <itemizedlist>
   <listitem>
    <para>Rename server parameter <varname>server_min_messages</> to <varname>log_min_messages</> (Bruce)</para>
    <para>
     This was done so most parameters that control the server logs
     begin with <literal>log_</>.
    </para>
   </listitem>

   <listitem><para>Rename <varname>show_*_stats</> to <varname>log_*_stats</> (Bruce)</para></listitem>
   <listitem><para>Rename <varname>show_source_port</> to <varname>log_source_port</> (Bruce)</para></listitem>
   <listitem><para>Rename <varname>hostname_lookup</> to <varname>log_hostname</> (Bruce)</para></listitem>

   <listitem>
    <para>Add <varname>checkpoint_warning</> to warn of excessive checkpointing (Bruce)</para>
    <para>
     In prior releases, it was difficult to determine if checkpoint
     was happening too frequently. This feature adds a warning to the
     server logs when excessive checkpointing happens.
    </para>
   </listitem>

   <listitem><para>New read-only server parameters for localization (Tom)</para></listitem>

   <listitem>
    <para>
     Change debug server log messages to output as <literal>DEBUG</>
     rather than <literal>LOG</> (Bruce)
    </para>
   </listitem>

   <listitem>
    <para>Prevent server log variables from being turned off by non-superusers (Bruce)</para>
    <para>
     This is a security feature so non-superusers cannot disable
     logging that was enabled by the administrator.
    </para>
   </listitem>

   <listitem>
    <para>
     <varname>log_min_messages</>/<varname>client_min_messages</> now
     controls <varname>debug_*</> output (Bruce)
    </para>
    <para>
     This centralizes client debug information so all debug output
     can be sent to either the client or server logs.
    </para>
   </listitem>

   <listitem>
    <para>Add Mac OS X Rendezvous server support (Chris Campbell)</para>
    <para>
     This allows Mac OS X hosts to query the network for available
     <productname>PostgreSQL</productname> servers.
    </para>
   </listitem>

   <listitem>
    <para>
     Add ability to print only slow statements using
     <varname>log_min_duration_statement</varname>
     (Christopher)
    </para>
    <para>
     This is an often requested debugging feature that allows
     administrators to see only slow queries in their server logs.
    </para>
   </listitem>

   <listitem>
    <para>Allow <filename>pg_hba.conf</filename> to accept netmasks in CIDR format (Andrew Dunstan)</para>
    <para>
     This allows administrators to merge the host IP address and
     netmask fields into a single CIDR field in <filename>pg_hba.conf</filename>.
    </para>
   </listitem>

   <listitem><para>New read-only parameter <varname>is_superuser</varname> (Tom)</para></listitem>

   <listitem>
    <para>New parameter <varname>log_error_verbosity</varname> to control error detail (Tom)</para>
    <para>
     This works with the new error reporting feature to supply
     additional error information like hints, file names and line
     numbers.
    </para>
   </listitem>

   <listitem>
    <para><literal>postgres --describe-config</literal> now dumps server config variables (Aizaz Ahmed, Peter)</para>
    <para>
     This option is useful for administration tools that need to know
     the configuration variable names and their minimums, maximums,
     defaults, and descriptions.
    </para>
   </listitem>

   <listitem>
    <para>
     Add new columns in <literal>pg_settings</literal>:
     <literal>context</>, <literal>type</>, <literal>source</>,
     <literal>min_val</>, <literal>max_val</> (Joe)
    </para>
   </listitem>

   <listitem>
    <para>
     Make default <varname>shared_buffers</> 1000 and
     <varname>max_connections</> 100, if possible (Tom)
    </para>
    <para>
     Prior versions defaulted to 64 shared buffers so <productname>PostgreSQL</productname>
     would start on even very old systems. This release tests the
     amount of shared memory allowed by the platform and selects more
     reasonable default values if possible.  Of course, users are
     still encouraged to evaluate their resource load and size
     <varname>shared_buffers</varname> accordingly.
    </para>
   </listitem>

   <listitem>
    <para>
     New <filename>pg_hba.conf</filename> record type
     <literal>hostnossl</> to prevent SSL connections (Jon
     Jensen)
    </para>
    <para>
     In prior releases, there was no way to prevent SSL connections
     if both the client and server supported SSL. This option allows
     that capability.
    </para>
   </listitem>

   <listitem>
    <para>
     Remove parameter <varname>geqo_random_seed</varname>
     (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Add server parameter <varname>regex_flavor</varname> to control regular expression processing (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Make <command>pg_ctl</command> better handle nonstandard ports (Greg)
    </para>
   </listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>Query Changes</title>

  <itemizedlist>
   <listitem><para>New SQL-standard information schema (Peter)</para></listitem>
   <listitem><para>Add read-only transactions (Peter)</para></listitem>
   <listitem><para>Print key name and value in foreign-key violation messages (Dmitry Tkach)</para></listitem>

   <listitem>
    <para>Allow users to see their own queries in <literal>pg_stat_activity</literal> (Kevin Brown)</para>
    <para>
     In prior releases, only the superuser could see query strings
     using <literal>pg_stat_activity</literal>. Now ordinary users
     can see their own query strings.
    </para>
   </listitem>

   <listitem>
    <para>Fix aggregates in subqueries to match SQL standard (Tom)</para>
    <para>
     The SQL standard says that an aggregate function appearing
     within a nested subquery belongs to the outer query if its
     argument contains only outer-query variables.  Prior
     <productname>PostgreSQL</productname> releases did not handle
     this fine point correctly.
    </para>
   </listitem>

   <listitem>
    <para>Add option to prevent auto-addition of tables referenced in query (Nigel J. Andrews)</para>
    <para>
     By default, tables mentioned in the query are automatically
     added to the <literal>FROM</> clause if they are not already
     there.  This is compatible with historic
     <productname>POSTGRES</productname> behavior but is contrary to
     the SQL standard.  This option allows selecting
     standard-compatible behavior.
    </para>
   </listitem>

   <listitem>
    <para>Allow <literal>UPDATE ... SET col = DEFAULT</literal> (Rod)</para>
    <para>
     This allows <command>UPDATE</command> to set a column to its
     declared default value.
    </para>
   </listitem>

   <listitem>
    <para>Allow expressions to be used in <literal>LIMIT</>/<literal>OFFSET</> (Tom)</para>
    <para>
     In prior releases, <literal>LIMIT</>/<literal>OFFSET</> could
     only use constants, not expressions.
    </para>
   </listitem>

   <listitem>
    <para>Implement <literal>CREATE TABLE AS EXECUTE</literal> (Neil, Peter)</para>
   </listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>Object Manipulation Changes</title>

  <itemizedlist>
   <listitem>
    <para>Make <command>CREATE SEQUENCE</command> grammar more conforming to SQL:2003 (Neil)</para>
   </listitem>

   <listitem>
    <para>Add statement-level triggers (Neil)</para>
    <para>
     While this allows a trigger to fire at the end of a statement,
     it does not allow the trigger to access all rows modified by the
     statement.  This capability is planned for a future release.
    </para>
   </listitem>

   <listitem>
    <para>Add check constraints for domains (Rod)</para>
    <para>
     This greatly increases the usefulness of domains by allowing
     them to use check constraints.
    </para>
   </listitem>

   <listitem>
    <para>Add <command>ALTER DOMAIN</command> (Rod)</para>
    <para>
     This allows manipulation of existing domains.
    </para>
   </listitem>

   <listitem>
    <para>Fix several zero-column table bugs (Tom)</para>
    <para>
     <productname>PostgreSQL</productname> supports zero-column tables. This fixes various bugs
     that occur when using such tables.
    </para>
   </listitem>

   <listitem>
    <para>Have <literal>ALTER TABLE ... ADD PRIMARY KEY</literal> add not-null constraint (Rod)</para>
    <para>
     In prior releases, <literal>ALTER TABLE ... ADD
     PRIMARY</literal> would add a unique index, but not a not-null
     constraint.  That is fixed in this release.
    </para>
   </listitem>

   <listitem><para>Add <literal>ALTER TABLE ... WITHOUT OIDS</literal> (Rod)</para>
    <para>
     This allows control over whether new and updated rows will have
     an OID column.  This is most useful for saving storage space.
    </para>
   </listitem>

   <listitem>
    <para>
     Add <literal>ALTER SEQUENCE</literal> to modify minimum, maximum,
     increment, cache, cycle values (Rod)
    </para>
   </listitem>

   <listitem>
    <para>Add <literal>ALTER TABLE ... CLUSTER ON</literal> (Alvaro Herrera)</para>
    <para>
     This command is used by <command>pg_dump</command> to record the
     cluster column for each table previously clustered. This
     information is used by database-wide cluster to cluster all
     previously clustered tables.
    </para>
   </listitem>

   <listitem><para>Improve automatic type casting for domains (Rod, Tom)</para></listitem>
   <listitem><para>Allow dollar signs in identifiers, except as first character (Tom)</para></listitem>
   <listitem><para>Disallow dollar signs in operator names, so <literal>x=$1</> works (Tom)</para></listitem>

   <listitem>
    <para>
     Allow copying table schema using <literal>LIKE
     <replaceable>subtable</replaceable></literal>, also SQL:2003
     feature <literal>INCLUDING DEFAULTS</literal> (Rod)
    </para>
   </listitem>

   <listitem>
    <para>
     Add <literal>WITH GRANT OPTION</literal> clause to
     <command>GRANT</command> (Peter)
    </para>
    <para>
     This enabled <command>GRANT</command> to give other users the
     ability to grant privileges on a object.
    </para>
   </listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>Utility Command Changes</title>

  <itemizedlist>
   <listitem>
    <para>Add <literal>ON COMMIT</literal> clause to <command>CREATE TABLE</command> for temporary tables (Gavin)</para>
    <para>
     This adds the ability for a table to be dropped or all rows
     deleted on transaction commit.
    </para>
   </listitem>

   <listitem>
    <para>Allow cursors outside transactions using <literal>WITH HOLD</literal> (Neil)</para>
    <para>
     In previous releases, cursors were removed at the end of the
     transaction that created them. Cursors can now be created with
     the <literal>WITH HOLD</literal> option, which allows them to
     continue to be accessed after the creating transaction has
     committed.
    </para>
   </listitem>

   <listitem>
    <para><literal>FETCH 0</literal> and <literal>MOVE 0 </literal> now do nothing (Bruce)</para>
    <para>
     In previous releases, <literal>FETCH 0</literal> fetched all
     remaining rows, and <literal>MOVE 0</literal> moved to the end
     of the cursor.
    </para>
   </listitem>

   <listitem>
    <para>
     Cause <command>FETCH</command> and <command>MOVE</command> to
     return the number of rows fetched/moved, or zero if at the
     beginning/end of cursor, per SQL standard (Bruce)
    </para>
    <para>
     In prior releases, the row count returned by
     <command>FETCH</command> and <command>MOVE</command> did not
     accurately reflect the number of rows processed.
    </para>
   </listitem>

   <listitem>
    <para>Properly handle <literal>SCROLL</literal> with cursors, or
    report an error (Neil)</para>
    <para>
     Allowing random access (both forward and backward scrolling) to
     some kinds of queries cannot be done without some additional
     work. If <literal>SCROLL</literal> is specified when the cursor
     is created, this additional work will be performed. Furthermore,
     if the cursor has been created with <literal>NO SCROLL</literal>,
     no random access is allowed.
    </para>
   </listitem>

   <listitem>
    <para>
     Implement SQL-compatible options <literal>FIRST</>,
     <literal>LAST</>, <literal>ABSOLUTE <replaceable>n</></>,
     <literal>RELATIVE <replaceable>n</></> for
     <command>FETCH</command> and <command>MOVE</command> (Tom)
    </para>
   </listitem>

   <listitem>
    <para>Allow <command>EXPLAIN</command> on <command>DECLARE CURSOR</command> (Tom)</para>
   </listitem>

   <listitem>
    <para>Allow <command>CLUSTER</command> to use index marked as pre-clustered by default (Alvaro Herrera)</para>
   </listitem>

   <listitem>
    <para>Allow <command>CLUSTER</command> to cluster all tables (Alvaro Herrera)</para>
    <para>
     This allows all previously clustered tables in a database to be
     reclustered with a single command.
    </para>
   </listitem>

   <listitem><para>Prevent <command>CLUSTER</command> on partial indexes (Tom)</para></listitem>

   <listitem><para>Allow DOS and Mac line-endings in <command>COPY</> files (Bruce)</para></listitem>

   <listitem>
    <para>
     Disallow literal carriage return as a data value,
     backslash-carriage-return and <literal>\r</> are still allowed
     (Bruce)
    </para>
   </listitem>

   <listitem>
    <para><command>COPY</> changes (binary, <literal>\.</>) (Tom)</para>
   </listitem>

   <listitem>
    <para>Recover from <command>COPY</command> failure cleanly (Tom)</para>
   </listitem>

   <listitem>
    <para>Prevent possible memory leaks in <command>COPY</command> (Tom)</para>
   </listitem>

   <listitem>
    <para>Make <command>TRUNCATE</command> transaction-safe (Rod)</para>
    <para>
     <command>TRUNCATE</command> can now be used inside a
     transaction. If the transaction aborts, the changes made by the
     <command>TRUNCATE</command> are automatically rolled back.
    </para>
   </listitem>

   <listitem>
    <para>
     Allow prepare/bind of utility commands like
     <command>FETCH</command> and <command>EXPLAIN</command> (Tom)
    </para>
   </listitem>

   <listitem>
    <para>Add <command>EXPLAIN EXECUTE</command> (Neil)</para>
   </listitem>

   <listitem>
    <para>Improve <command>VACUUM</command> performance on indexes by reducing WAL traffic (Tom)</para>
   </listitem>

   <listitem>
    <para>Functional indexes have been generalized into indexes on expressions (Tom)</para>
    <para>
     In prior releases, functional indexes only supported a simple
     function applied to one or more column names.  This release
     allows any type of scalar expression.
    </para>
   </listitem>

   <listitem>
    <para>
     Have <command>SHOW TRANSACTION ISOLATION</command> match input
     to <command>SET TRANSACTION ISOLATION</command>
     (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
      Have <command>COMMENT ON DATABASE</command> on nonlocal
      database generate a warning, rather than an error (Rod)
     </para>

    <para>
     Database comments are stored in database-local tables so
     comments on a database have to be stored in each database.
    </para>
   </listitem>

   <listitem>
    <para>
     Improve reliability of <command>LISTEN</>/<command>NOTIFY</> (Tom)
    </para>
   </listitem>

   <listitem>
    <para>Allow <command>REINDEX</command> to reliably reindex nonshared system catalog indexes (Tom)</para>
    <para>
     This allows system tables to be reindexed without the
     requirement of a standalone session, which was necessary in
     previous releases. The only tables that now require a standalone
     session for reindexing are the global system tables
     <literal>pg_database</>, <literal>pg_shadow</>, and
     <literal>pg_group</>.
    </para>
   </listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>Data Type and Function Changes</title>

  <itemizedlist>
   <listitem>
    <para>
     New server parameter <varname>extra_float_digits</varname> to
     control precision display of floating-point numbers (Pedro
     Ferreira, Tom)
    </para>
    <para>
     This controls output precision which was causing regression
     testing problems.
    </para>
   </listitem>

   <listitem><para>Allow <literal>+1300</literal> as a numeric time-zone specifier, for FJST (Tom)</para></listitem>

   <listitem>
    <para>
     Remove rarely used functions <function>oidrand</>,
     <function>oidsrand</>, and <function>userfntest</> functions
     (Neil)
    </para>
   </listitem>

   <listitem>
    <para>Add <function>md5()</> function to main server, already in <filename>contrib/pgcrypto</filename> (Joe)</para>
    <para>
     An MD5 function was frequently requested. For more complex
     encryption capabilities, use
     <filename>contrib/pgcrypto</filename>.
    </para>
   </listitem>

   <listitem><para>Increase date range of <type>timestamp</type> (John Cochran)</para></listitem>

   <listitem>
    <para>
     Change <literal>EXTRACT(EPOCH FROM timestamp)</literal> so
     <type>timestamp without time zone</type> is assumed to be in
     local time, not GMT (Tom)
    </para>
   </listitem>

   <listitem><para>Trap division by zero in case the operating system doesn't prevent it (Tom)</para></listitem>
   <listitem><para>Change the <type>numeric</type> data type internally to base 10000 (Tom)</para></listitem>
   <listitem><para>New <function>hostmask()</function> function (Greg Wickham)</para></listitem>
   <listitem><para>Fixes for <function>to_char()</function> and <function>to_timestamp()</function> (Karel)</para></listitem>

   <listitem>
    <para>
     Allow functions that can take any argument data type and return
     any data type, using <type>anyelement</type> and
     <type>anyarray</type> (Joe)
    </para>
    <para>
     This allows the creation of functions that can work with any
     data type.
    </para>
   </listitem>

   <listitem>
    <para>
     Arrays can now be specified as <literal>ARRAY[1,2,3]</literal>,
     <literal>ARRAY[['a','b'],['c','d']]</literal>, or
     <literal>ARRAY[ARRAY[ARRAY[2]]]</literal> (Joe)
    </para>
   </listitem>

   <listitem>
    <para>
     Allow proper comparisons for arrays, including <literal>ORDER
     BY</literal> and <literal>DISTINCT</literal> support
     (Joe)
    </para>
   </listitem>

   <listitem><para>Allow indexes on array columns (Joe)</para></listitem>
   <listitem><para>Allow array concatenation with <literal>||</literal> (Joe)</para></listitem>

   <listitem>
    <para>
     Allow <literal>WHERE</literal> qualification
     <literal><replaceable>expr</> <replaceable>op</> ANY/SOME/ALL
     (<replaceable>array_expr</>)</literal> (Joe)
    </para>
    <para>
     This allows arrays to behave like a list of values, for purposes
     like <literal>SELECT * FROM tab WHERE col IN
     (array_val)</literal>.
    </para>
   </listitem>

   <listitem>
    <para>
     New array functions <function>array_append</>,
     <function>array_cat</>, <function>array_lower</>,
     <function>array_prepend</>, <function>array_to_string</>,
     <function>array_upper</>, <function>string_to_array</> (Joe)
    </para>
   </listitem>

   <listitem><para>Allow user defined aggregates to use polymorphic functions (Joe)</para></listitem>
   <listitem><para>Allow assignments to empty arrays (Joe)</para></listitem>

   <listitem>
    <para>
     Allow 60 in seconds fields of <type>time</type>,
     <type>timestamp</type>, and <type>interval</type> input values
     (Tom)
    </para>
    <para>
     Sixty-second values are needed for leap seconds.
    </para>
   </listitem>

   <listitem><para>Allow <type>cidr</type> data type to be cast to <type>text</type> (Tom)</para></listitem>

   <listitem><para>Disallow invalid time zone names in SET TIMEZONE</para></listitem>

   <listitem>
    <para>
     Trim trailing spaces when <type>char</type> is cast to
     <type>varchar</> or <type>text</> (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Make <type>float(<replaceable>p</>)</> measure the precision
     <replaceable>p</> in binary digits, not decimal digits
     (Tom)
    </para>
   </listitem>

   <listitem>
    <para>Add IPv6 support to the <type>inet</type> and <type>cidr</type> data types (Michael Graff)</para>
   </listitem>

   <listitem>
    <para>Add <function>family()</function> function to report whether address is IPv4 or IPv6 (Michael Graff)</para>
   </listitem>

   <listitem>
    <para>
     Have <literal>SHOW datestyle</literal> generate output similar
     to that used by <literal>SET datestyle</literal> (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Make <literal>EXTRACT(TIMEZONE)</literal> and <literal>SET/SHOW
     TIME ZONE</literal> follow the SQL convention for the sign of
     time zone offsets, i.e., positive is east from UTC (Tom)
    </para>
   </listitem>

   <listitem>
    <para>Fix <literal>date_trunc('quarter', ...)</literal> (Böjthe Zoltán)</para>
    <para>
     Prior releases returned an incorrect value for this function call.
    </para>
   </listitem>

   <listitem>
    <para>Make <function>initcap()</function> more compatible with Oracle (Mike Nolan)</para>
    <para>
     <function>initcap()</function> now uppercases a letter appearing
     after any non-alphanumeric character, rather than only after
     whitespace.
    </para>
   </listitem>

   <listitem>
    <para>Allow only <varname>datestyle</varname> field order for date values not in ISO-8601 format (Greg)</para>
   </listitem>

   <listitem>
    <para>
     Add new <varname>datestyle</varname> values <literal>MDY</>,
     <literal>DMY</>, and <literal>YMD</> to set input field order;
     honor <literal>US</> and <literal>European</> for backward
     compatibility (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     String literals like <literal>'now'</literal> or
     <literal>'today'</literal> will no longer work as a column
     default. Use functions such as <function>now()</function>,
     <function>current_timestamp</function> instead.  (change
     required for prepared statements) (Tom)
    </para>
   </listitem>

   <listitem>
    <para>Treat NaN as larger than any other value in <function>min()</>/<function>max()</> (Tom)</para>
    <para>
     NaN was already sorted after ordinary numeric values for most
     purposes, but <function>min()</> and <function>max()</> didn't
     get this right.
    </para>
   </listitem>

   <listitem>
    <para>Prevent interval from suppressing <literal>:00</literal>
    seconds display</para>
   </listitem>

   <listitem>
    <para>
     New functions <function>pg_get_triggerdef(prettyprint)</function>
     and <function>pg_conversion_is_visible()</function> (Christopher)
    </para>
   </listitem>

   <listitem>
    <para>Allow time to be specified as <literal>040506</> or <literal>0405</> (Tom)</para>
   </listitem>

   <listitem>
    <para>
     Input date order must now be <literal>YYYY-MM-DD</literal> (with 4-digit year) or
     match <varname>datestyle</varname>
    </para>
   </listitem>

   <listitem>
    <para>
     Make <function>pg_get_constraintdef</function> support
     unique, primary-key, and check constraints (Christopher)
    </para>
   </listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>Server-Side Language Changes</title>

  <itemizedlist>
   <listitem>
    <para>
     Prevent PL/pgSQL crash when <literal>RETURN NEXT</literal> is
     used on a zero-row record variable (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Make PL/Python's <function>spi_execute</function> interface
     handle null values properly (Andrew Bosma)
    </para>
   </listitem>

   <listitem>
    <para>Allow PL/pgSQL to declare variables of composite types without <literal>%ROWTYPE</literal> (Tom)</para>
   </listitem>

   <listitem>
    <para>Fix PL/Python's <function>_quote()</function> function to handle big integers</para>
   </listitem>

   <listitem>
    <para>Make PL/Python an untrusted language, now called <literal>plpythonu</literal> (Kevin Jacobs, Tom)</para>
    <para>
     The Python language no longer supports a restricted execution
     environment, so the trusted version of PL/Python was removed. If
     this situation changes, a version of PL/Python that can be used
     by non-superusers will be readded.
    </para>
   </listitem>

   <listitem>
    <para>Allow polymorphic PL/pgSQL functions (Joe, Tom)</para>
   </listitem>

   <listitem>
    <para>Allow polymorphic SQL functions (Joe)</para>
   </listitem>

   <listitem>
    <para>
     Improved compiled function caching mechanism in PL/pgSQL with
     full support for polymorphism (Joe)
    </para>
   </listitem>

   <listitem>
    <para>
     Add new parameter <literal>$0</> in PL/pgSQL representing the
     function's actual return type (Joe)
    </para>
   </listitem>

   <listitem>
    <para>
     Allow PL/Tcl and PL/Python to use the same trigger on multiple tables (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Fixed PL/Tcl's <function>spi_prepare</function> to accept fully
     qualified type names in the parameter type list
     (Jan)
    </para>
   </listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>psql Changes</title>

  <itemizedlist>
   <listitem>
    <para>Add <literal>\pset pager always</literal> to always use pager (Greg)</para>
    <para>
     This forces the pager to be used even if the number of rows is
     less than the screen height.  This is valuable for rows that
     wrap across several screen rows.
    </para>
   </listitem>

   <listitem><para>Improve tab completion (Rod, Ross Reedstrom, Ian Barwick)</para></listitem>
   <listitem><para>Reorder <literal>\?</> help into groupings (Harald Armin Massa, Bruce)</para></listitem>
   <listitem><para>Add backslash commands for listing schemas, casts, and conversions (Christopher)</para></listitem>

   <listitem>
    <para>
     <command>\encoding</> now changes based on the server parameter
     <varname>client_encoding</varname> (Tom)
    </para>
    <para>
     In previous versions, <command>\encoding</command> was not aware
     of encoding changes made using <literal>SET
     client_encoding</literal>.
    </para>
   </listitem>

   <listitem>
    <para>Save editor buffer into readline history (Ross)</para>
    <para>
     When <command>\e</> is used to edit a query, the result is saved
     in the readline history for retrieval using the up arrow.
    </para>
   </listitem>

   <listitem><para>Improve <command>\d</command> display (Christopher)</para></listitem>
   <listitem><para>Enhance HTML mode to be more standards-conforming (Greg)</para></listitem>

   <listitem>
    <para>New <command>\set AUTOCOMMIT off</command> capability (Tom)</para>
    <para>
     This takes the place of the removed server parameter <varname>autocommit</varname>.
    </para>
   </listitem>

   <listitem>
    <para>New <command>\set VERBOSITY</command> to control error detail (Tom)</para>
    <para>
     This controls the new error reporting details.
    </para>
   </listitem>

   <listitem><para>New prompt escape sequence <literal>%x</literal> to show transaction status (Tom)</para></listitem>
   <listitem><para>Long options for <application>psql</application> are now available on all platforms</para></listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>pg_dump Changes</title>

  <itemizedlist>
   <listitem><para>Multiple pg_dump fixes, including tar format and large objects</para></listitem>
   <listitem><para>Allow pg_dump to dump specific schemas (Neil)</para></listitem>

   <listitem>
    <para>Make pg_dump preserve column storage characteristics (Christopher)</para>
    <para>
     This preserves <literal>ALTER TABLE ... SET STORAGE</literal> information.
    </para>
   </listitem>

   <listitem><para>Make pg_dump preserve <command>CLUSTER</command> characteristics (Christopher)</para></listitem>

   <listitem>
    <para>
     Have pg_dumpall use <command>GRANT</>/<command>REVOKE</> to dump database-level privileges (Tom)
    </para>
   </listitem>

   <listitem>
    <para>
     Allow pg_dumpall to support the options <option>-a</>,
     <option>-s</>, <option>-x</> of pg_dump (Tom)
    </para>
   </listitem>

   <listitem><para>Prevent pg_dump from lowercasing identifiers specified on the command line (Tom)</para></listitem>

   <listitem>
    <para>
     pg_dump options <option>--use-set-session-authorization</option>
     and <option>--no-reconnect</option> now do nothing, all dumps
     use <command>SET SESSION AUTHORIZATION</command>
    </para>
    <para>
     pg_dump no longer reconnects to switch users, but instead always
     uses <command>SET SESSION AUTHORIZATION</command>. This will
     reduce password prompting during restores.
    </para>
   </listitem>

   <listitem>
    <para>Long options for <application>pg_dump</application> are now available on all platforms</para>
    <para>
     <productname>PostgreSQL</productname> now includes its own
     long-option processing routines.
    </para>
   </listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>libpq Changes</title>

  <itemizedlist>
   <listitem>
    <para>
     Add function <function>PQfreemem</function> for freeing memory on
     Windows, suggested for <command>NOTIFY</command> (Bruce)
    </para>
    <para>
     Windows requires that memory allocated in a library be freed by
     a function in the same library, hence
     <function>free()</function> doesn't work for freeing memory
     allocated by libpq. <function>PQfreemem</function> is the proper
     way to free libpq memory, especially on Windows, and is
     recommended for other platforms as well.
    </para>
   </listitem>

   <listitem>
    <para>Document service capability, and add sample file (Bruce)</para>
    <para>
     This allows clients to look up connection information in a
     central file on the client machine.
    </para>
   </listitem>

   <listitem>
    <para>
     Make <function>PQsetdbLogin</function> have the same defaults as
     <function>PQconnectdb</function> (Tom)
    </para>
   </listitem>

   <listitem><para>Allow libpq to cleanly fail when result sets are too large (Tom)</para></listitem>

   <listitem>
    <para>
     Improve performance of function <function>PQunescapeBytea</function> (Ben Lamb)
    </para>
   </listitem>

   <listitem>
    <para>
     Allow thread-safe libpq with <filename>configure</filename>
     option <option>--enable-thread-safety</option> (Lee Kindness,
     Philip Yarra)
    </para>
   </listitem>

   <listitem>
    <para>
     Allow function <function>pqInternalNotice</function> to accept a
     format string and arguments instead of just a preformatted
     message (Tom, Sean Chittenden)
    </para>
   </listitem>

   <listitem>
    <para>
     Control SSL negotiation with <literal>sslmode</literal> values
     <literal>disable</literal>, <literal>allow</literal>,
     <literal>prefer</literal>, and <literal>require</literal> (Jon
     Jensen)
    </para>
   </listitem>

   <listitem>
    <para>Allow new error codes and levels of text (Tom)</para>
   </listitem>

   <listitem>
    <para>Allow access to the underlying table and column of a query result (Tom)</para>
    <para>
     This is helpful for query-builder applications that want to know
     the underlying table and column names associated with a specific
     result set.
    </para>
   </listitem>

   <listitem><para>Allow access to the current transaction status (Tom)</para></listitem>
   <listitem><para>Add ability to pass binary data directly to the server (Tom)</para></listitem>

   <listitem>
    <para>
     Add function <function>PQexecPrepared</function> and
     <function>PQsendQueryPrepared</function> functions which perform
     bind/execute of previously prepared statements (Tom)
     </para>
    </listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>JDBC Changes</title>

  <itemizedlist>
   <listitem><para>Allow <function>setNull</function> on updateable result sets</para></listitem>
   <listitem><para>Allow <function>executeBatch</function> on a prepared statement (Barry)</para></listitem>
   <listitem><para>Support SSL connections (Barry)</para></listitem>
   <listitem><para>Handle schema names in result sets (Paul Sorenson)</para></listitem>
   <listitem><para>Add refcursor support (Nic Ferrier)</para></listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>Miscellaneous Interface Changes</title>

  <itemizedlist>
   <listitem>
    <para>Prevent possible memory leak or core dump during libpgtcl shutdown (Tom)</para>
   </listitem>
   <listitem>
    <para>Add Informix compatibility to ECPG (Michael)</para>
    <para>
     This allows ECPG to process embedded C programs that were
     written using certain Informix extensions.
    </para>
   </listitem>

   <listitem>
    <para>Add type <type>decimal</type> to ECPG that is fixed length, for Informix (Michael)</para>
   </listitem>

   <listitem>
    <para>
     Allow thread-safe embedded SQL programs with
     <filename>configure</filename> option
     <option>--enable-thread-safety</option> (Lee Kindness, Bruce)
    </para>
    <para>
     This allows multiple threads to access the database at the same
     time.
    </para>
   </listitem>

   <listitem>
    <para>Moved Python client PyGreSQL to <ulink url="http://www.pygresql.org"></ulink> (Marc)</para>
   </listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>Source Code Changes</title>

  <itemizedlist>
   <listitem><para>Prevent need for separate platform geometry regression result files (Tom)</para></listitem>
   <listitem><para>Improved PPC locking primitive (Reinhard Max)</para></listitem>
   <listitem><para>New function <function>palloc0</function> to allocate and clear memory (Bruce)</para></listitem>
   <listitem><para>Fix locking code for s390x CPU (64-bit) (Tom)</para></listitem>
   <listitem><para>Allow OpenBSD to use local ident credentials (William Ahern)</para></listitem>
   <listitem><para>Make query plan trees read-only to executor (Tom)</para></listitem>
   <listitem><para>Add Darwin startup scripts (David Wheeler)</para></listitem>
   <listitem><para>Allow libpq to compile with Borland C++ compiler (Lester Godwin, Karl Waclawek)</para></listitem>
   <listitem><para>Use our own version of <function>getopt_long()</function> if needed (Peter)</para></listitem>
   <listitem><para>Convert administration scripts to C (Peter)</para></listitem>
   <listitem><para> Bison &gt;= 1.85 is now required to build the <productname>PostgreSQL</> grammar, if building from CVS</para></listitem>
   <listitem><para>Merge documentation into one book (Peter)</para></listitem>
   <listitem><para>Add Windows compatibility functions (Bruce)</para></listitem>
   <listitem><para>Allow client interfaces to compile under MinGW (Bruce)</para></listitem>
   <listitem><para>New <function>ereport()</function> function for error reporting (Tom)</para></listitem>
   <listitem><para>Support Intel compiler on Linux (Peter)</para></listitem>
   <listitem><para>Improve Linux startup scripts (Slawomir Sudnik, Darko Prenosil)</para></listitem>
   <listitem><para>Add support for AMD Opteron and Itanium (Jeffrey W. Baker, Bruce)</para></listitem>
   <listitem>
    <para>Remove <option>--enable-recode</option> option from <command>configure</command></para>
    <para>
     This was no longer needed now that we have <command>CREATE CONVERSION</command>.
    </para>
   </listitem>
   <listitem>
    <para>Generate a compile error if spinlock code is not found (Bruce)</para>
    <para>
     Platforms without spinlock code will now fail to compile, rather
     than silently using semaphores. This failure can be disabled
     with a new <command>configure</command> option.
    </para>
   </listitem>
  </itemizedlist>
 </sect3>

 <sect3>
  <title>Contrib Changes</title>

  <itemizedlist>
   <listitem><para>Change dbmirror license to BSD</para></listitem>
   <listitem><para>Improve earthdistance (Bruno Wolff III)</para></listitem>
   <listitem><para>Portability improvements to pgcrypto (Marko Kreen)</para></listitem>
   <listitem><para>Prevent crash in xml (John Gray, Michael Richards)</para></listitem>
   <listitem><para>Update oracle</para></listitem>
   <listitem><para>Update mysql</para></listitem>
   <listitem><para>Update cube (Bruno Wolff III)</para></listitem>
   <listitem><para>Update earthdistance to use cube (Bruno Wolff III)</para></listitem>
   <listitem><para>Update btree_gist (Oleg)</para></listitem>
   <listitem><para>New tsearch2 full-text search module (Oleg, Teodor)</para></listitem>
   <listitem><para>Add hash-based crosstab function to tablefuncs (Joe)</para></listitem>
   <listitem><para>Add serial column to order <function>connectby()</> siblings in tablefuncs (Nabil Sayegh,Joe)</para></listitem>
   <listitem><para>Add named persistent connections to dblink (Shridhar Daithanka)</para></listitem>
   <listitem><para>New pg_autovacuum allows automatic <command>VACUUM</command> (Matthew T. O'Connor)</para></listitem>
   <listitem><para>Make pgbench honor environment variables <envar>PGHOST</>, <envar>PGPORT</>, <envar>PGUSER</> (Tatsuo)</para></listitem>
   <listitem><para>Improve intarray (Teodor Sigaev)</para></listitem>
   <listitem><para>Improve pgstattuple (Rod)</para></listitem>
   <listitem><para>Fix bug in <function>metaphone()</function> in fuzzystrmatch</para></listitem>
   <listitem><para>Improve adddepend (Rod)</para></listitem>
   <listitem><para>Update spi/timetravel (Böjthe Zoltán)</para></listitem>
   <listitem><para>Fix dbase <option>-s</> option and improve non-ASCII handling (Thomas Behr, Márcio Smiderle)</para></listitem>
   <listitem><para>Remove array module because features now included by default (Joe)</para></listitem>
  </itemizedlist>
 </sect3>
 </sect2>
</sect1>

 <sect1 id="release-7-3-20">
  <title>Release 7.3.20</title>

  <note>
  <title>Release date</title>
  <simpara>2007-09-17</simpara>
  </note>

  <para>
   This release contains fixes from 7.3.19.
  </para>

  <sect2>
   <title>Migration to Version 7.3.20</title>

   <para>
    A dump/restore is not required for those running 7.3.X.  However,
    if you are upgrading from a version earlier than 7.3.13, see the release
    notes for 7.3.13.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Prevent index corruption when a transaction inserts rows and
      then aborts close to the end of a concurrent <command>VACUUM</>
      on the same table (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Make <command>CREATE DOMAIN ... DEFAULT NULL</> work properly (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix crash when <varname>log_min_error_statement</> logging runs out
      of memory (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Require non-superusers who use <filename>/contrib/dblink</> to use only
      password authentication, as a security measure (Joe)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-3-19">
  <title>Release 7.3.19</title>

  <note>
  <title>Release date</title>
  <simpara>2007-04-23</simpara>
  </note>

  <para>
   This release contains fixes from 7.3.18,
   including a security fix.
  </para>

  <sect2>
   <title>Migration to Version 7.3.19</title>

   <para>
    A dump/restore is not required for those running 7.3.X.  However,
    if you are upgrading from a version earlier than 7.3.13, see the release
    notes for 7.3.13.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
    <para>
     Support explicit placement of the temporary-table schema within
     <varname>search_path</>, and disable searching it for functions
     and operators (Tom)
    </para>
    <para>
     This is needed to allow a security-definer function to set a
     truly secure value of <varname>search_path</>.  Without it,
     an unprivileged SQL user can use temporary objects to execute code
     with the privileges of the security-definer function (CVE-2007-2138).
     See <command>CREATE FUNCTION</> for more information.
    </para>
    </listitem>

    <listitem>
    <para>
     Fix potential-data-corruption bug in how <command>VACUUM FULL</> handles
     <command>UPDATE</> chains (Tom, Pavan Deolasee)
    </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-3-18">
  <title>Release 7.3.18</title>

  <note>
  <title>Release date</title>
  <simpara>2007-02-05</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.3.17, including
   a security fix.
  </para>

  <sect2>
   <title>Migration to Version 7.3.18</title>

   <para>
    A dump/restore is not required for those running 7.3.X.  However,
    if you are upgrading from a version earlier than 7.3.13, see the release
    notes for 7.3.13.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
    <para>
     Remove security vulnerability that allowed connected users
     to read backend memory (Tom)
    </para>
    <para>
     The vulnerability involves changing the
     data type of a table column used in a SQL function (CVE-2007-0555).
     This error can easily be exploited to cause a backend crash, and in
     principle might be used to read database content that the user
     should not be able to access.
    </para>
    </listitem>

    <listitem>
    <para>
     Fix rare bug wherein btree index page splits could fail
     due to choosing an infeasible split point (Heikki Linnakangas)
    </para>
    </listitem>

    <listitem>
    <para>
     Tighten security of multi-byte character processing for UTF8 sequences
     over three bytes long (Tom)
    </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-3-17">
  <title>Release 7.3.17</title>

  <note>
  <title>Release date</title>
  <simpara>2007-01-08</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.3.16.
  </para>

  <sect2>
   <title>Migration to Version 7.3.17</title>

   <para>
    A dump/restore is not required for those running 7.3.X.  However,
    if you are upgrading from a version earlier than 7.3.13, see the release
    notes for 7.3.13.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      <function>to_number()</> and <function>to_char(numeric)</>
      are now <literal>STABLE</>, not <literal>IMMUTABLE</>, for
      new <application>initdb</> installs (Tom)
     </para>

     <para>
      This is because <varname>lc_numeric</> can potentially
      change the output of these functions.
     </para>
    </listitem>

    <listitem>
     <para>
      Improve index usage of regular expressions that use parentheses (Tom)
     </para>

     <para>
      This improves <application>psql</> <literal>\d</> performance also.
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-3-16">
  <title>Release 7.3.16</title>

  <note>
  <title>Release date</title>
  <simpara>2006-10-16</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.3.15.
  </para>

  <sect2>
   <title>Migration to Version 7.3.16</title>

   <para>
    A dump/restore is not required for those running 7.3.X.  However,
    if you are upgrading from a version earlier than 7.3.13, see the release
    notes for 7.3.13.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Fix corner cases in pattern matching for
 <application>psql</>'s <literal>\d</> commands</para></listitem>
<listitem><para>Fix index-corrupting bugs in /contrib/ltree
 (Teodor)</para></listitem>
<listitem><para>Back-port 7.4 spinlock code to improve performance and support
64-bit architectures better</para> </listitem>
<listitem><para>Fix SSL-related memory leak in libpq</para> </listitem>
<listitem><para>Fix backslash escaping in /contrib/dbmirror</para></listitem>
<listitem><para>Adjust regression tests for recent changes in US DST laws
</para> </listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-3-15">
  <title>Release 7.3.15</title>

  <note>
  <title>Release date</title>
  <simpara>2006-05-23</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.3.14,
   including patches for extremely serious security issues.
  </para>

  <sect2>
   <title>Migration to Version 7.3.15</title>

   <para>
    A dump/restore is not required for those running 7.3.X.  However,
    if you are upgrading from a version earlier than 7.3.13, see the release
    notes for 7.3.13.
   </para>

   <para>
    Full security against the SQL-injection attacks described in
    CVE-2006-2313 and CVE-2006-2314 might require changes in application
    code.  If you have applications that embed untrustworthy strings
    into SQL commands, you should examine them as soon as possible to
    ensure that they are using recommended escaping techniques.  In
    most cases, applications should be using subroutines provided by
    libraries or drivers (such as <application>libpq</>'s
    <function>PQescapeStringConn()</>) to perform string escaping,
    rather than relying on <foreignphrase>ad hoc</> code to do it.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Change the server to reject invalidly-encoded multibyte
characters in all cases (Tatsuo, Tom)</para>
<para>While <productname>PostgreSQL</> has been moving in this direction for
some time, the checks are now applied uniformly to all encodings and all
textual input, and are now always errors not merely warnings.  This change
defends against SQL-injection attacks of the type described in CVE-2006-2313.
</para></listitem>

<listitem><para>Reject unsafe uses of <literal>\'</> in string literals</para>
<para>As a server-side defense against SQL-injection attacks of the type
described in CVE-2006-2314, the server now only accepts <literal>''</> and not
<literal>\'</> as a representation of ASCII single quote in SQL string
literals.  By default, <literal>\'</> is rejected only when
<varname>client_encoding</> is set to a client-only encoding (SJIS, BIG5, GBK,
GB18030, or UHC), which is the scenario in which SQL injection is possible.
A new configuration parameter <varname>backslash_quote</> is available to
adjust this behavior when needed.  Note that full security against
CVE-2006-2314 might require client-side changes; the purpose of
<varname>backslash_quote</> is in part to make it obvious that insecure
clients are insecure.
</para></listitem>

<listitem><para>Modify <application>libpq</>'s string-escaping routines to be
aware of encoding considerations</para>
<para>This fixes <application>libpq</>-using applications for the security
issues described in CVE-2006-2313 and CVE-2006-2314.
Applications that use multiple <productname>PostgreSQL</> connections
concurrently should migrate to <function>PQescapeStringConn()</> and
<function>PQescapeByteaConn()</> to ensure that escaping is done correctly
for the settings in use in each database connection.  Applications that
do string escaping <quote>by hand</> should be modified to rely on library
routines instead.
</para></listitem>

<listitem><para>Fix some incorrect encoding conversion functions</para>
<para><function>win1251_to_iso</>, <function>alt_to_iso</>,
<function>euc_tw_to_big5</>, <function>euc_tw_to_mic</>,
<function>mic_to_euc_tw</> were all broken to varying
extents.
</para></listitem>

<listitem><para>Clean up stray remaining uses of <literal>\'</> in strings
(Bruce, Jan)</para></listitem>

<listitem><para>Fix server to use custom DH SSL parameters correctly (Michael
Fuhr)</para></listitem>

<listitem><para>Fix various minor memory leaks</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-3-14">
  <title>Release 7.3.14</title>

  <note>
  <title>Release date</title>
  <simpara>2006-02-14</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.3.13.
  </para>

  <sect2>
   <title>Migration to Version 7.3.14</title>

   <para>
    A dump/restore is not required for those running 7.3.X.  However,
    if you are upgrading from a version earlier than 7.3.13, see the release
    notes for 7.3.13.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>

<listitem><para>Fix potential crash in <command>SET
SESSION AUTHORIZATION</> (CVE-2006-0553)</para>
<para>An unprivileged user could crash the server process, resulting in
momentary denial of service to other users, if the server has been compiled
with Asserts enabled (which is not the default).
Thanks to Akio Ishida for reporting this problem.
</para></listitem>

<listitem><para>Fix bug with row visibility logic in self-inserted
rows (Tom)</para>
<para>Under rare circumstances a row inserted by the current command
could be seen as already valid, when it should not be.  Repairs bug
created in 7.3.11 release.
</para></listitem>

<listitem><para>Fix race condition that could lead to <quote>file already
exists</> errors during pg_clog file creation
(Tom)</para></listitem>

<listitem><para>Fix to allow restoring dumps that have cross-schema
references to custom operators (Tom)</para></listitem>

<listitem><para>Portability fix for testing presence of <function>finite</>
and <function>isinf</> during configure (Tom)</para></listitem>

</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-3-13">
  <title>Release 7.3.13</title>

  <note>
  <title>Release date</title>
  <simpara>2006-01-09</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.3.12.
  </para>

  <sect2>
   <title>Migration to Version 7.3.13</title>

   <para>
    A dump/restore is not required for those running 7.3.X.  However,
    if you are upgrading from a version earlier than 7.3.10, see the release
    notes for 7.3.10.
    Also, you might need to <command>REINDEX</> indexes on textual
    columns after updating, if you are affected by the locale or
    <application>plperl</> issues described below.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>

<listitem><para>Fix character string comparison for locales that consider
different character combinations as equal, such as Hungarian (Tom)</para>
<para>This might require <command>REINDEX</> to fix existing indexes on
textual columns.</para></listitem>

<listitem><para>Set locale environment variables during postmaster startup
to ensure that <application>plperl</> won't change the locale later</para>
<para>This fixes a problem that occurred if the <application>postmaster</> was
started with environment variables specifying a different locale than what
<application>initdb</> had been told.  Under these conditions, any use of
<application>plperl</> was likely to lead to corrupt indexes.  You might need
<command>REINDEX</> to fix existing indexes on
textual columns if this has happened to you.</para></listitem>

<listitem><para>Fix longstanding bug in strpos() and regular expression
handling in certain rarely used Asian multi-byte character sets (Tatsuo)
</para></listitem>

<listitem><para>Fix bug in <filename>/contrib/pgcrypto</> gen_salt,
which caused it not to use all available salt space for MD5 and
XDES algorithms (Marko Kreen, Solar Designer)</para>
<para>Salts for Blowfish and standard DES are unaffected.</para></listitem>

<listitem><para>Fix <filename>/contrib/dblink</> to throw an error,
rather than crashing, when the number of columns specified is different from
what's actually returned by the query (Joe)</para></listitem>

</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-3-12">
  <title>Release 7.3.12</title>

  <note>
  <title>Release date</title>
  <simpara>2005-12-12</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.3.11.
  </para>

  <sect2>
   <title>Migration to Version 7.3.12</title>

   <para>
    A dump/restore is not required for those running 7.3.X.  However,
    if you are upgrading from a version earlier than 7.3.10, see the release
    notes for 7.3.10.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>

<listitem><para>Fix race condition in transaction log management</para>
<para>There was a narrow window in which an I/O operation could be initiated
for the wrong page, leading to an Assert failure or data
corruption.</para>
</listitem>

<listitem><para><filename>/contrib/ltree</> fixes (Teodor)</para></listitem>

<listitem><para>Fix longstanding planning error for outer joins</para>
<para>This bug sometimes caused a bogus error <quote>RIGHT JOIN is
only supported with merge-joinable join conditions</>.</para></listitem>

<listitem><para>Prevent core dump in <application>pg_autovacuum</> when a
table has been dropped</para></listitem>

</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-3-11">
  <title>Release 7.3.11</title>

  <note>
  <title>Release date</title>
  <simpara>2005-10-04</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.3.10.
  </para>

  <sect2>
   <title>Migration to Version 7.3.11</title>

   <para>
    A dump/restore is not required for those running 7.3.X.  However,
    if you are upgrading from a version earlier than 7.3.10, see the release
    notes for 7.3.10.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Fix error that allowed <command>VACUUM</> to remove
<literal>ctid</> chains too soon, and add more checking in code that follows
<literal>ctid</> links</para>
<para>This fixes a long-standing problem that could cause crashes in very rare
circumstances.</para></listitem>
<listitem><para>Fix <type>CHAR()</> to properly pad spaces to the specified
length when using a multiple-byte character set (Yoshiyuki Asaba)</para>
<para>In prior releases, the padding of <type>CHAR()</> was incorrect
because it only padded to the specified number of bytes without
considering how many characters were stored.</para></listitem>
<listitem><para>Fix missing rows in queries like <literal>UPDATE a=... WHERE
a...</> with GiST index on column <literal>a</></para></listitem>
<listitem><para>Improve checking for partially-written WAL
pages</para></listitem>
<listitem><para>Improve robustness of signal handling when SSL is
enabled</para></listitem>
<listitem><para>Various memory leakage fixes</para></listitem>
<listitem><para>Various portability improvements</para></listitem>
<listitem><para>Fix PL/PgSQL to handle <literal>var := var</> correctly when
the variable is of pass-by-reference type</para></listitem>
</itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-7-3-10">
  <title>Release 7.3.10</title>

  <note>
  <title>Release date</title>
  <simpara>2005-05-09</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.3.9, including several
   security-related issues.
  </para>

  <sect2>
   <title>Migration to Version 7.3.10</title>

   <para>
    A dump/restore is not required for those running 7.3.X.  However,
    it is one possible way of handling a significant security problem
    that has been found in the initial contents of 7.3.X system
    catalogs.  A dump/initdb/reload sequence using 7.3.10's initdb will
    automatically correct this problem.
   </para>

   <para>
    The security problem is that the built-in character set encoding
    conversion functions can be invoked from SQL commands by unprivileged
    users, but the functions were not designed for such use and are not
    secure against malicious choices of arguments.  The fix involves changing
    the declared parameter list of these functions so that they can no longer
    be invoked from SQL commands.  (This does not affect their normal use
    by the encoding conversion machinery.)
    It is strongly recommended that all installations repair this error,
    either by initdb or by following the manual repair procedure given
    below.  The error at least allows unprivileged database users to crash
    their server process, and might allow unprivileged users to gain the
    privileges of a database superuser.
   </para>

   <para>
    If you wish not to do an initdb, perform the following procedure instead.
    As the database superuser, do:

<programlisting>
BEGIN;
UPDATE pg_proc SET proargtypes[3] = 'internal'::regtype
WHERE pronamespace = 11 AND pronargs = 5
     AND proargtypes[2] = 'cstring'::regtype;
-- The command should report having updated 90 rows;
-- if not, rollback and investigate instead of committing!
COMMIT;
</programlisting>
   </para>

   <para>
    The above procedure must be carried out in <emphasis>each</> database
    of an installation, including <literal>template1</>, and ideally
    including <literal>template0</> as well.  If you do not fix the
    template databases then any subsequently created databases will contain
    the same error.  <literal>template1</> can be fixed in the same way
    as any other database, but fixing <literal>template0</> requires
    additional steps.  First, from any database issue:
<programlisting>
UPDATE pg_database SET datallowconn = true WHERE datname = 'template0';
</programlisting>
     Next connect to <literal>template0</> and perform the above repair
     procedure.  Finally, do:
<programlisting>
-- re-freeze template0:
VACUUM FREEZE;
-- and protect it against future alterations:
UPDATE pg_database SET datallowconn = false WHERE datname = 'template0';
</programlisting>
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Change encoding function signature to prevent
misuse</para></listitem>
<listitem><para>Repair ancient race condition that allowed a transaction to be
seen as committed for some purposes (eg SELECT FOR UPDATE) slightly sooner
than for other purposes</para>
<para>This is an extremely serious bug since it could lead to apparent
data inconsistencies being briefly visible to applications.</para></listitem>
<listitem><para>Repair race condition between relation extension and
VACUUM</para>
<para>This could theoretically have caused loss of a page's worth of
freshly-inserted data, although the scenario seems of very low probability.
There are no known cases of it having caused more than an Assert failure.
</para></listitem>
<listitem><para>Fix comparisons of <type>TIME WITH TIME ZONE</> values</para>
<para>
The comparison code was wrong in the case where the
<literal>--enable-integer-datetimes</> configuration switch had been used.
NOTE: if you have an index on a <type>TIME WITH TIME ZONE</> column,
it will need to be <command>REINDEX</>ed after installing this update, because
the fix corrects the sort order of column values.
</para></listitem>
<listitem><para>Fix <function>EXTRACT(EPOCH)</> for
<type>TIME WITH TIME ZONE</> values</para></listitem>
<listitem><para>Fix mis-display of negative fractional seconds in
<type>INTERVAL</> values</para>
<para>
This error only occurred when the
<literal>--enable-integer-datetimes</> configuration switch had been used.
</para></listitem>
<listitem><para>Additional buffer overrun checks in plpgsql
(Neil)</para></listitem>
<listitem><para>Fix pg_dump to dump trigger names containing <literal>%</>
correctly (Neil)</para></listitem>
<listitem><para>Prevent <function>to_char(interval)</> from dumping core for
month-related formats</para></listitem>
<listitem><para>Fix <filename>contrib/pgcrypto</> for newer OpenSSL builds
(Marko Kreen)</para></listitem>
<listitem><para>Still more 64-bit fixes for
<filename>contrib/intagg</></para></listitem>
<listitem><para>Prevent incorrect optimization of functions returning
<type>RECORD</></para></listitem>
</itemizedlist>

 </sect2>
</sect1>

 <sect1 id="release-7-3-9">
  <title>Release 7.3.9</title>

  <note>
  <title>Release date</title>
  <simpara>2005-01-31</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.3.8, including several
   security-related issues.
  </para>

  <sect2>
   <title>Migration to Version 7.3.9</title>

   <para>
    A dump/restore is not required for those running 7.3.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Disallow <command>LOAD</> to non-superusers</para>
<para>
On platforms that will automatically execute initialization functions of a
shared library (this includes at least Windows and ELF-based Unixen),
<command>LOAD</> can be used to make the server execute arbitrary code.
Thanks to NGS Software for reporting this.</para></listitem>
<listitem><para>Check that creator of an aggregate function has the right to
execute the specified transition functions</para>
<para>
This oversight made it possible to bypass denial of EXECUTE
permission on a function.</para></listitem>
<listitem><para>Fix security and 64-bit issues in
contrib/intagg</para></listitem>
<listitem><para>Add needed STRICT marking to some contrib functions (Kris
Jurka)</para></listitem>
<listitem><para>Avoid buffer overrun when plpgsql cursor declaration has too
many parameters (Neil)</para></listitem>
<listitem><para>Fix planning error for FULL and RIGHT outer joins</para>
<para>
The result of the join was mistakenly supposed to be sorted the same as the
left input.  This could not only deliver mis-sorted output to the user, but
in case of nested merge joins could give outright wrong answers.
</para></listitem>
<listitem><para>Fix plperl for quote marks in tuple fields</para></listitem>
<listitem><para>Fix display of negative intervals in SQL and GERMAN
datestyles</para></listitem>
</itemizedlist>

 </sect2>
</sect1>

 <sect1 id="release-7-3-8">
  <title>Release 7.3.8</title>

  <note>
  <title>Release date</title>
  <simpara>2004-10-22</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.3.7.
  </para>


  <sect2>
   <title>Migration to Version 7.3.8</title>

   <para>
    A dump/restore is not required for those running 7.3.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Repair possible failure to update hint bits on disk</para>
<para>
Under rare circumstances this oversight could lead to
<quote>could not access transaction status</> failures, which qualifies
it as a potential-data-loss bug.
</para></listitem>
<listitem><para>Ensure that hashed outer join does not miss tuples</para>
<para>
Very large left joins using a hash join plan could fail to output unmatched
left-side rows given just the right data distribution.
</para></listitem>
<listitem><para>Disallow running pg_ctl as root</para>
<para>
This is to guard against any possible security issues.
</para></listitem>
<listitem><para>Avoid using temp files in /tmp in make_oidjoins_check</para>
<para>
This has been reported as a security issue, though it's hardly worthy of
concern since there is no reason for non-developers to use this script anyway.
</para></listitem>
</itemizedlist>

 </sect2>
</sect1>

 <sect1 id="release-7-3-7">
  <title>Release 7.3.7</title>

  <note>
  <title>Release date</title>
  <simpara>2004-08-16</simpara>
  </note>

  <para>
   This release contains one critical fix over 7.3.6, and some minor items.
  </para>


  <sect2>
   <title>Migration to Version 7.3.7</title>

   <para>
    A dump/restore is not required for those running 7.3.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Prevent possible loss of committed transactions during crash</para>
<para>
Due to insufficient interlocking between transaction commit and checkpointing,
it was possible for transactions committed just before the most recent
checkpoint to be lost, in whole or in part, following a database crash and
restart.  This is a serious bug that has existed
since <productname>PostgreSQL</productname> 7.1.
</para></listitem>
<listitem><para>Remove asymmetrical word processing in tsearch (Teodor)</para></listitem>
<listitem><para>Properly schema-qualify function names when pg_dump'ing a CAST</para></listitem>
</itemizedlist>

 </sect2>
</sect1>

 <sect1 id="release-7-3-6">
  <title>Release 7.3.6</title>

  <note>
  <title>Release date</title>
  <simpara>2004-03-02</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.3.5.
  </para>


  <sect2>
   <title>Migration to Version 7.3.6</title>

   <para>
    A dump/restore is <emphasis>not</emphasis> required for those
    running 7.3.*.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Revert erroneous changes in rule permissions checking</para>
<para>A patch applied in 7.3.3 to fix a corner case in rule permissions checks
turns out to have disabled rule-related permissions checks in many
not-so-corner cases.  This would for example allow users to insert into views
they weren't supposed to have permission to insert into.  We have therefore
reverted the 7.3.3 patch.  The original bug will be fixed in 8.0.
</para></listitem>
<listitem><para>Repair incorrect order of operations in
GetNewTransactionId()</para>
<para>
This bug could result in failure under out-of-disk-space conditions, including
inability to restart even after disk space is freed.
</para></listitem>
<listitem><para>Ensure configure selects -fno-strict-aliasing even when
an external value for CFLAGS is supplied</para>
<para>
On some platforms, building with -fstrict-aliasing causes bugs.
</para></listitem>
<listitem><para>Make pg_restore handle 64-bit off_t correctly</para>
<para>
This bug prevented proper restoration from archive files exceeding 4 GB.
</para></listitem>
<listitem><para>Make contrib/dblink not assume that local and remote type OIDs
match (Joe)</para></listitem>
<listitem><para>Quote connectby()'s start_with argument properly (Joe)</para></listitem>
<listitem><para>Don't crash when a rowtype argument to a plpgsql function is
NULL</para></listitem>
<listitem><para>Avoid generating invalid character encoding sequences in
corner cases when planning LIKE operations</para></listitem>
<listitem><para>Ensure text_position() cannot scan past end of source string
in multibyte cases (Korea PostgreSQL Users' Group)</para></listitem>
<listitem><para>Fix index optimization and selectivity estimates for LIKE
operations on bytea columns (Joe)</para></listitem>
</itemizedlist>

 </sect2>
</sect1>

 <sect1 id="release-7-3-5">
  <title>Release 7.3.5</title>

  <note>
  <title>Release date</title>
  <simpara>2003-12-03</simpara>
  </note>

  <para>
   This has a variety of fixes from 7.3.4.
  </para>


  <sect2>
   <title>Migration to Version 7.3.5</title>

   <para>
    A dump/restore is <emphasis>not</emphasis> required for those
    running 7.3.*.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Force zero_damaged_pages to be on during recovery from WAL</para></listitem>
<listitem><para>Prevent some obscure cases of <quote>variable not in subplan target lists</quote></para></listitem>
<listitem><para>Force stats processes to detach from shared memory, ensuring cleaner shutdown</para></listitem>
<listitem><para>Make PQescapeBytea and byteaout consistent with each other (Joe)</para></listitem>
<listitem><para>Added missing SPI_finish() calls to dblink's get_tuple_of_interest() (Joe)</para></listitem>
<listitem><para>Fix for possible foreign key violation when rule rewrites INSERT (Jan)</para></listitem>
<listitem><para>Support qualified type names in PL/Tcl's spi_prepare command (Jan)</para></listitem>
<listitem><para>Make pg_dump handle a procedural language handler located in pg_catalog</para></listitem>
<listitem><para>Make pg_dump handle cases where a custom opclass is in another schema</para></listitem>
<listitem><para>Make pg_dump dump binary-compatible casts correctly (Jan)</para></listitem>
<listitem><para>Fix insertion of expressions containing subqueries into rule bodies</para></listitem>
<listitem><para>Fix incorrect argument processing in clusterdb script (Anand Ranganathan)</para></listitem>
<listitem><para>Fix problems with dropped columns in plpython triggers</para></listitem>
<listitem><para>Repair problems with to_char() reading past end of its input string (Karel)</para></listitem>
<listitem><para>Fix GB18030 mapping errors (Tatsuo)</para></listitem>
<listitem><para>Fix several problems with SSL error handling and asynchronous SSL I/O</para></listitem>
<listitem><para>Remove ability to bind a list of values to a single parameter in JDBC
(prevents possible SQL-injection attacks)</para></listitem>
<listitem><para>Fix some errors in HAVE_INT64_TIMESTAMP code paths</para></listitem>
<listitem><para>Fix corner case for btree search in parallel with first root page split</para></listitem>
</itemizedlist>

 </sect2>
</sect1>

 <sect1 id="release-7-3-4">
  <title>Release 7.3.4</title>

  <note>
  <title>Release date</title>
  <simpara>2003-07-24</simpara>
  </note>

  <para>
   This has a variety of fixes from 7.3.3.
  </para>


  <sect2>
   <title>Migration to Version 7.3.4</title>

   <para>
    A dump/restore is <emphasis>not</emphasis> required for those
    running 7.3.*.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Repair breakage in timestamp-to-date conversion for dates before 2000</para></listitem>
<listitem><para>Prevent rare possibility of server startup failure (Tom)</para></listitem>
<listitem><para>Fix bugs in interval-to-time conversion (Tom)</para></listitem>
<listitem><para>Add constraint names in a few places in pg_dump (Rod)</para></listitem>
<listitem><para>Improve performance of functions with many parameters (Tom)</para></listitem>
<listitem><para>Fix to_ascii() buffer overruns (Tom)</para></listitem>
<listitem><para>Prevent restore of database comments from throwing an error (Tom)</para></listitem>
<listitem><para>Work around buggy strxfrm() present in some Solaris releases (Tom)</para></listitem>
<listitem><para>Properly escape jdbc setObject() strings to improve security (Barry)</para></listitem>
</itemizedlist>
  </sect2>
 </sect1>


<sect1 id="release-7-3-3">
 <title>Release 7.3.3</title>

 <note>
  <title>Release date</title>
  <simpara>2003-05-22</simpara>
 </note>

 <para>
  This release contains a variety of fixes for version 7.3.2.
 </para>

 <sect2>
  <title>Migration to Version 7.3.3</title>

  <para>
   A dump/restore is <emphasis>not</emphasis> required for those
   running version 7.3.*.
  </para>
 </sect2>

 <sect2>
  <title>Changes</title>

<itemizedlist>
<listitem><para>Repair sometimes-incorrect computation of StartUpID after a crash</para></listitem>
<listitem><para>Avoid slowness with lots of deferred triggers in one transaction (Stephan)</para></listitem>
<listitem><para>Don't lock referenced row when <command>UPDATE</command> doesn't change foreign key's value (Jan)</para></listitem>
<listitem><para>Use <command>-fPIC</command> not <command>-fpic</command> on Sparc (Tom Callaway)</para></listitem>
<listitem><para>Repair lack of schema-awareness in contrib/reindexdb</para></listitem>
<listitem><para>Fix contrib/intarray error for zero-element result array (Teodor)</para></listitem>
<listitem><para>Ensure createuser script will exit on control-C (Oliver)</para></listitem>
<listitem><para>Fix errors when the type of a dropped column has itself been dropped</para></listitem>
<listitem><para><command>CHECKPOINT</command> does not cause database panic on failure in noncritical steps</para></listitem>
<listitem><para>Accept 60 in seconds fields of timestamp, time, interval input values</para></listitem>
<listitem><para>Issue notice, not error, if <type>TIMESTAMP</type>,
<type> TIME</type>, or <type>INTERVAL</type> precision too large</para></listitem>
<listitem><para>Fix <function>abstime-to-time</function> cast function (fix is
      not applied unless you <application>initdb</application>)</para></listitem>
<listitem><para>Fix <application>pg_proc</application> entry for
     <type>timestampt_izone</type> (fix is not applied unless you
       <application>initdb</application>)</para></listitem>
<listitem><para>Make <function>EXTRACT(EPOCH FROM timestamp without time zone)</function> treat input as local time</para></listitem>
<listitem><para><command>'now'::timestamptz</command> gave wrong answer if timezone changed earlier in transaction</para></listitem>
<listitem><para><envar>HAVE_INT64_TIMESTAMP</envar> code for time with timezone overwrote its input</para></listitem>
<listitem><para>Accept <command>GLOBAL TEMP/TEMPORARY</command> as a
      synonym for <command>TEMPORARY</command></para></listitem>
<listitem><para>Avoid improper schema-privilege-check failure in foreign-key triggers</para></listitem>
<listitem><para>Fix bugs in foreign-key triggers for <command>SET DEFAULT</command> action</para></listitem>
<listitem><para>Fix incorrect time-qual check in row fetch for
      <command>UPDATE</command> and <command>DELETE</command> triggers</para></listitem>
<listitem><para>Foreign-key clauses were parsed but ignored in
      <command>ALTER TABLE ADD COLUMN</command></para></listitem>
<listitem><para>Fix createlang script breakage for case where handler function already exists</para></listitem>
<listitem><para>Fix misbehavior on zero-column tables in <application>pg_dump</application>, COPY, ANALYZE, other places</para></listitem>
<listitem><para>Fix misbehavior of <function>func_error()</function> on type names containing '%'</para></listitem>
<listitem><para>Fix misbehavior of <function>replace()</function> on strings containing '%'</para></listitem>
<listitem><para>Regular-expression patterns containing certain multibyte characters failed</para></listitem>
<listitem><para>Account correctly for <command>NULL</command>s in more cases in join size estimation</para></listitem>
<listitem><para>Avoid conflict with system definition of <function>isblank()</function> function or macro</para></listitem>
<listitem><para>Fix failure to convert large code point values in EUC_TW conversions (Tatsuo)</para></listitem>
<listitem><para>Fix error recovery for <function>SSL_read</function>/<function>SSL_write</function> calls</para></listitem>
<listitem><para>Don't do early constant-folding of type coercion expressions</para></listitem>
<listitem><para>Validate page header fields immediately after reading in any page</para></listitem>
<listitem><para>Repair incorrect check for ungrouped variables in unnamed joins</para></listitem>
<listitem><para>Fix buffer overrun in <function>to_ascii</function> (Guido Notari)</para></listitem>
<listitem><para>contrib/ltree fixes (Teodor)</para></listitem>
<listitem><para>Fix core dump in deadlock detection on machines where char is unsigned</para></listitem>
<listitem><para>Avoid running out of buffers in many-way indexscan (bug introduced in 7.3)</para></listitem>
<listitem><para>Fix planner's selectivity estimation functions to handle domains properly</para></listitem>
<listitem><para>Fix <application>dbmirror</application> memory-allocation bug (Steven Singer)</para></listitem>
<listitem><para>Prevent infinite loop in <function>ln(numeric)</function> due to roundoff error</para></listitem>
<listitem><para><command>GROUP BY</command> got confused if there were multiple equal GROUP BY items</para></listitem>
<listitem><para>Fix bad plan when inherited <command>UPDATE</command>/<command>DELETE</command> references another inherited table</para></listitem>
<listitem><para>Prevent clustering on incomplete (partial or non-NULL-storing) indexes</para></listitem>
<listitem><para>Service shutdown request at proper time if it arrives while still starting up</para></listitem>
<listitem><para>Fix left-links in temporary indexes (could make backwards scans miss entries)</para></listitem>
<listitem><para>Fix incorrect handling of client_encoding setting in postgresql.conf (Tatsuo)</para></listitem>
<listitem><para>Fix failure to respond to <command>pg_ctl stop -m fast</command> after Async_NotifyHandler runs</para></listitem>
<listitem><para>Fix SPI for case where rule contains multiple statements of the same type</para></listitem>
<listitem><para>Fix problem with checking for wrong type of access privilege in rule query</para></listitem>
<listitem><para>Fix problem with <command>EXCEPT</command> in <command>CREATE RULE</command></para></listitem>
<listitem><para>Prevent problem with dropping temp tables having serial columns</para></listitem>
<listitem><para>Fix replace_vars_with_subplan_refs failure in complex views</para></listitem>
<listitem><para>Fix regexp slowness in single-byte encodings (Tatsuo)</para></listitem>
<listitem><para>Allow qualified type names in <command>CREATE CAST</command>
      and <command> DROP CAST</command></para></listitem>
<listitem><para>Accept <function>SETOF type[]</function>, which formerly had to
      be written <function>SETOF _type</function></para></listitem>
<listitem><para>Fix <application>pg_dump</application> core dump in some cases with procedural languages</para></listitem>
<listitem><para>Force ISO datestyle in <application>pg_dump</application> output, for portability (Oliver)</para></listitem>
<listitem><para><application>pg_dump</application> failed to handle error return
      from <function>lo_read</function> (Oleg Drokin)</para></listitem>
<listitem><para><application>pg_dumpall</application> failed with groups having no members (Nick Eskelinen)</para></listitem>
<listitem><para><application>pg_dumpall</application> failed to recognize --globals-only switch</para></listitem>
<listitem><para>pg_restore failed to restore blobs if -X disable-triggers is specified</para></listitem>
<listitem><para>Repair intrafunction memory leak in plpgsql</para></listitem>
<listitem><para>pltcl's <command>elog</command> command dumped core if given wrong parameters (Ian Harding)</para></listitem>
<listitem><para>plpython used wrong value of <envar>atttypmod</envar> (Brad McLean)</para></listitem>
<listitem><para>Fix improper quoting of boolean values in Python interface (D'Arcy)</para></listitem>
<listitem><para>Added <function>addDataType()</function> method to PGConnection interface for JDBC</para></listitem>
<listitem><para>Fixed various problems with updateable ResultSets for JDBC (Shawn Green)</para></listitem>
<listitem><para>Fixed various problems with DatabaseMetaData for JDBC (Kris Jurka, Peter Royal)</para></listitem>
<listitem><para>Fixed problem with parsing table ACLs in JDBC</para></listitem>
<listitem><para>Better error message for character set conversion problems in JDBC</para></listitem>
</itemizedlist>
 </sect2>
</sect1>


<sect1 id="release-7-3-2">
 <title>Release 7.3.2</title>

 <note>
  <title>Release date</title>
  <simpara>2003-02-04</simpara>
 </note>

 <para>
  This release contains a variety of fixes for version 7.3.1.
 </para>


 <sect2>
  <title>Migration to Version 7.3.2</title>

  <para>
   A dump/restore is <emphasis>not</emphasis> required for those
   running version 7.3.*.
  </para>
 </sect2>

 <sect2>
  <title>Changes</title>

<itemizedlist>
<listitem><para>Restore creation of OID column in CREATE TABLE AS / SELECT INTO</para></listitem>
<listitem><para>Fix <application>pg_dump</> core dump when dumping views having comments</para></listitem>
<listitem><para>Dump DEFERRABLE/INITIALLY DEFERRED constraints properly</para></listitem>
<listitem><para>Fix UPDATE when child table's column numbering differs from parent</para></listitem>
<listitem><para>Increase default value of max_fsm_relations</para></listitem>
<listitem><para>Fix problem when fetching backwards in a cursor for a single-row query</para></listitem>
<listitem><para>Make backward fetch work properly with cursor on SELECT DISTINCT query</para></listitem>
<listitem><para>Fix problems with loading <application>pg_dump</> files containing contrib/lo usage</para></listitem>
<listitem><para>Fix problem with all-numeric user names</para></listitem>
<listitem><para>Fix possible memory leak and core dump during disconnect in libpgtcl</para></listitem>
<listitem><para>Make plpython's spi_execute command handle nulls properly (Andrew Bosma)</para></listitem>
<listitem><para>Adjust plpython error reporting so that its regression test passes again</para></listitem>
<listitem><para>Work with bison 1.875</para></listitem>
<listitem><para>Handle mixed-case names properly in plpgsql's %type (Neil)</para></listitem>
<listitem><para>Fix core dump in pltcl when executing a query rewritten by a rule</para></listitem>
<listitem><para>Repair array subscript overruns (per report from Yichen Xie)</para></listitem>
<listitem><para>Reduce MAX_TIME_PRECISION from 13 to 10 in floating-point case</para></listitem>
<listitem><para>Correctly case-fold variable names in per-database and per-user settings</para></listitem>
<listitem><para>Fix coredump in plpgsql's RETURN NEXT when SELECT into record returns no rows</para></listitem>
<listitem><para>Fix outdated use of pg_type.typprtlen in python client interface</para></listitem>
<listitem><para>Correctly handle fractional seconds in timestamps in JDBC driver</para></listitem>
<listitem><para>Improve performance of getImportedKeys() in JDBC</para></listitem>
<listitem><para>Make shared-library symlinks work standardly on HPUX (Giles)</para></listitem>
<listitem><para>Repair inconsistent rounding behavior for timestamp, time, interval</para></listitem>
<listitem><para>SSL negotiation fixes (Nathan Mueller)</para></listitem>
<listitem><para>Make libpq's ~/.pgpass feature work when connecting with PQconnectDB</para></listitem>
<listitem><para>Update my2pg, ora2pg</para></listitem>
<listitem><para>Translation updates</para></listitem>
<listitem><para>Add casts between types lo and oid in contrib/lo</para></listitem>
<listitem><para>fastpath code now checks for privilege to call function</para></listitem>
</itemizedlist>
 </sect2>
</sect1>


<sect1 id="release-7-3-1">
 <title>Release 7.3.1</title>

 <note>
  <title>Release date</title>
  <simpara>2002-12-18</simpara>
 </note>

 <para>
  This release contains a variety of fixes for version 7.3.
 </para>


 <sect2>
  <title>Migration to Version 7.3.1</title>

  <para>
   A dump/restore is <emphasis>not</emphasis> required for those
   running version 7.3. However, it should be noted that the main
   <productname>PostgreSQL</productname> interface library, libpq,
   has a new major version number for this release, which might require
   recompilation of client code in certain cases.
  </para>
 </sect2>

 <sect2>
  <title>Changes</title>

<itemizedlist>
<listitem><para>Fix a core dump of COPY TO when client/server encodings don't match (Tom)</para></listitem>
<listitem><para>Allow <application>pg_dump</> to work with pre-7.2 servers (Philip)</para></listitem>
<listitem><para>contrib/adddepend fixes (Tom)</para></listitem>
<listitem><para>Fix problem with deletion of per-user/per-database config settings (Tom)</para></listitem>
<listitem><para>contrib/vacuumlo fix (Tom)</para></listitem>
<listitem><para>Allow 'password' encryption even when pg_shadow contains MD5 passwords (Bruce)</para></listitem>
<listitem><para>contrib/dbmirror fix (Steven Singer)</para></listitem>
<listitem><para>Optimizer fixes (Tom)</para></listitem>
<listitem><para>contrib/tsearch fixes (Teodor Sigaev, Magnus)</para></listitem>
<listitem><para>Allow locale names to be mixed case (Nicolai Tufar)</para></listitem>
<listitem><para>Increment libpq library's major version number (Bruce)</para></listitem>
<listitem><para>pg_hba.conf error reporting fixes (Bruce, Neil)</para></listitem>
<listitem><para>Add SCO Openserver 5.0.4 as a supported platform (Bruce)</para></listitem>
<listitem><para>Prevent EXPLAIN from crashing server (Tom)</para></listitem>
<listitem><para>SSL fixes (Nathan Mueller)</para></listitem>
<listitem><para>Prevent composite column creation via ALTER TABLE (Tom)</para></listitem>
</itemizedlist>
 </sect2>
</sect1>


<sect1 id="release-7-3">
 <title>Release 7.3</title>

 <note>
  <title>Release date</title>
  <simpara>2002-11-27</simpara>
 </note>

 <sect2>
  <title>Overview</title>

  <para>
   Major changes in this release:
  </para>

  <variablelist>
   <varlistentry>
    <term>Schemas</term>
    <listitem>
     <para>
      Schemas allow users to create objects in separate namespaces,
      so two people or applications can have tables with the same
      name. There is also a public schema for shared tables.
      Table/index creation can be restricted by removing privileges
      on the public schema.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Drop Column</term>
    <listitem>
     <para>
      <productname>PostgreSQL</productname> now supports the
      <literal>ALTER TABLE ... DROP COLUMN</literal> functionality.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Table Functions</term>
    <listitem>
     <para>
      Functions returning multiple rows and/or multiple columns are
      now much easier to use than before.  You can call such a
      <quote>table function</quote> in the <literal>SELECT</literal>
      <literal>FROM</literal> clause, treating its output like a
      table. Also, <application>PL/pgSQL</application> functions can
      now return sets.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Prepared Queries</term>
    <listitem>
     <para>
      <productname>PostgreSQL</productname> now supports prepared
      queries, for improved performance.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Dependency Tracking</term>
    <listitem>
     <para>
      <productname>PostgreSQL</productname> now records object
      dependencies, which allows improvements in many areas.
      <command>DROP</command> statements now take either
      <literal>CASCADE</> or <literal>RESTRICT</> to control whether
      dependent objects are also dropped.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Privileges</term>
    <listitem>
     <para>
      Functions and procedural languages now have privileges, and
      functions can be defined to run with the privileges of their
      creator.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Internationalization</term>
    <listitem>
     <para>
      Both multibyte and locale support are now always enabled.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Logging</term>
    <listitem>
     <para>
      A variety of logging options have been enhanced.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Interfaces</term>
    <listitem>
     <para>
      A large number of interfaces have been moved to <ulink
      url="http://gborg.postgresql.org">http://gborg.postgresql.org</>
      where they can be developed and released independently.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Functions/Identifiers</term>
    <listitem>
     <para>
      By default, functions can now take up to 32 parameters, and
      identifiers can be up to 63 bytes long.  Also, <literal>OPAQUE</>
      is now deprecated: there are specific <quote>pseudo-datatypes</>
      to represent each of the former meanings of <literal>OPAQUE</>
      in function argument and result types.
     </para>
    </listitem>
   </varlistentry>

  </variablelist>
 </sect2>

 <sect2>
  <title>Migration to Version 7.3</title>

  <para>
   A dump/restore using <application>pg_dump</> is required for those
   wishing to migrate data from any previous release. If your
   application examines the system catalogs, additional changes will
   be required due to the introduction of schemas in 7.3; for more
   information, see: <ulink
   url="http://developer.postgresql.org/~momjian/upgrade_tips_7.3"></>.
  </para>

  <para>
   Observe the following incompatibilities:
  </para>

  <itemizedlist>
   <listitem>
    <para>
     Pre-6.3 clients are no longer supported.
    </para>
   </listitem>

   <listitem>
    <para>
     <filename>pg_hba.conf</filename> now has a column for the user
     name and additional features.  Existing files need to be
     adjusted.
    </para>
   </listitem>

   <listitem>
    <para>
     Several <filename>postgresql.conf</filename> logging parameters
     have been renamed.
    </para>
   </listitem>

   <listitem>
    <para>
     <literal>LIMIT #,#</literal> has been disabled; use
     <literal>LIMIT # OFFSET #</literal>.
    </para>
   </listitem>

   <listitem>
    <para>
     <command>INSERT</command> statements with column lists must
     specify a value for each specified column. For example,
     <literal>INSERT INTO tab (col1, col2) VALUES ('val1')</literal>
     is now invalid.  It's still allowed to supply fewer columns than
     expected if the <command>INSERT</command> does not have a column list.
    </para>
   </listitem>

   <listitem>
    <para>
     <type>serial</type> columns are no longer automatically
     <literal>UNIQUE</>; thus, an index will not automatically be
     created.
    </para>
   </listitem>

   <listitem>
    <para>
     A <command>SET</command> command inside an aborted transaction
     is now rolled back.
    </para>
   </listitem>

   <listitem>
    <para>
     <command>COPY</command> no longer considers missing trailing
     columns to be null.  All columns need to be specified.
     (However, one can achieve a similar effect by specifying a
     column list in the <command>COPY</command> command.)
    </para>
   </listitem>

   <listitem>
    <para>
     The data type <type>timestamp</type> is now equivalent to
     <type>timestamp without time zone</type>, instead of
     <type>timestamp with time zone</type>.
    </para>
   </listitem>

   <listitem>
    <para>
     Pre-7.3 databases loaded into 7.3 will not have the new object
     dependencies for <type>serial</type> columns, unique
     constraints, and foreign keys. See the directory
     <filename>contrib/adddepend/</filename> for a detailed
     description and a script that will add such dependencies.
    </para>
   </listitem>

   <listitem>
    <para>
     An empty string (<literal>''</literal>) is no longer allowed as
     the input into an integer field.  Formerly, it was silently
     interpreted as 0.
    </para>
   </listitem>

  </itemizedlist>
 </sect2>

 <sect2>
  <title>Changes</title>

  <sect3>
   <title>Server Operation</title>
<itemizedlist>
<listitem><para>Add pg_locks view to show locks (Neil)</para></listitem>
<listitem><para>Security fixes for password negotiation memory allocation (Neil)</para></listitem>
<listitem><para>Remove support for version 0 FE/BE protocol (<productname>PostgreSQL</productname> 6.2 and earlier) (Tom)</para></listitem>
<listitem><para>Reserve the last few backend slots for superusers, add parameter superuser_reserved_connections to control this (Nigel J. Andrews)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Performance</title>
<itemizedlist>
<listitem><para>Improve startup by calling localtime() only once (Tom)</para></listitem>
<listitem><para>Cache system catalog information in flat files for faster startup (Tom)</para></listitem>
<listitem><para>Improve caching of index information (Tom)</para></listitem>
<listitem><para>Optimizer improvements (Tom, Fernando Nasser)</para></listitem>
<listitem><para>Catalog caches now store failed lookups (Tom)</para></listitem>
<listitem><para>Hash function improvements (Neil)</para></listitem>
<listitem><para>Improve performance of query tokenization and network handling (Peter)</para></listitem>
<listitem><para>Speed improvement for large object restore (Mario Weilguni)</para></listitem>
<listitem><para>Mark expired index entries on first lookup, saving later heap fetches (Tom)</para></listitem>
<listitem><para>Avoid excessive NULL bitmap padding (Manfred Koizar)</para></listitem>
<listitem><para>Add BSD-licensed qsort() for Solaris, for performance (Bruce)</para></listitem>
<listitem><para>Reduce per-row overhead by four bytes (Manfred Koizar)</para></listitem>
<listitem><para>Fix GEQO optimizer bug (Neil Conway)</para></listitem>
<listitem><para>Make WITHOUT OID actually save four bytes per row (Manfred Koizar)</para></listitem>
<listitem><para>Add default_statistics_target variable to specify ANALYZE buckets (Neil)</para></listitem>
<listitem><para>Use local buffer cache for temporary tables so no WAL overhead (Tom)</para></listitem>
<listitem><para>Improve free space map performance on large tables (Stephen Marshall, Tom)</para></listitem>
<listitem><para>Improved WAL write concurrency (Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Privileges</title>
<itemizedlist>
<listitem><para>Add privileges on functions and procedural languages (Peter)</para></listitem>
<listitem><para>Add OWNER to CREATE DATABASE so superusers can create databases on behalf of unprivileged users (Gavin Sherry, Tom)</para></listitem>
<listitem><para>Add new object privilege bits EXECUTE and USAGE (Tom)</para></listitem>
<listitem><para>Add SET SESSION AUTHORIZATION DEFAULT and RESET SESSION AUTHORIZATION (Tom)</para></listitem>
<listitem><para>Allow functions to be executed with the privilege of the function owner (Peter)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Server Configuration</title>
<itemizedlist>
<listitem><para>Server log messages now tagged with LOG, not DEBUG (Bruce)</para></listitem>
<listitem><para>Add user column to pg_hba.conf (Bruce)</para></listitem>
<listitem><para>Have log_connections output two lines in log file (Tom)</para></listitem>
<listitem><para>Remove debug_level from postgresql.conf, now server_min_messages (Bruce)</para></listitem>
<listitem><para>New ALTER DATABASE/USER ... SET command for per-user/database initialization (Peter)</para></listitem>
<listitem><para>New parameters server_min_messages and client_min_messages to control which messages are sent to the server logs or client applications (Bruce)</para></listitem>
<listitem><para>Allow pg_hba.conf to specify lists of users/databases separated by commas, group names prepended with +, and file names prepended with @ (Bruce)</para></listitem>
<listitem><para>Remove secondary password file capability and pg_password utility (Bruce)</para></listitem>
<listitem><para>Add variable db_user_namespace for database-local user names (Bruce)</para></listitem>
<listitem><para>SSL improvements (Bear Giles)</para></listitem>
<listitem><para>Make encryption of stored passwords the default (Bruce)</para></listitem>
<listitem><para>Allow pg_statistics to be reset by calling pg_stat_reset() (Christopher)</para></listitem>
<listitem><para>Add log_duration parameter (Bruce)</para></listitem>
<listitem><para>Rename debug_print_query to log_statement (Bruce)</para></listitem>
<listitem><para>Rename show_query_stats to show_statement_stats (Bruce)</para></listitem>
<listitem><para>Add param log_min_error_statement to print commands to logs on error (Gavin)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Queries</title>
<itemizedlist>
<listitem><para>Make cursors insensitive, meaning their contents do not change (Tom)</para></listitem>
<listitem><para>Disable LIMIT #,# syntax; now only LIMIT # OFFSET # supported (Bruce)</para></listitem>
<listitem><para>Increase identifier length to 63 (Neil, Bruce)</para></listitem>
<listitem><para>UNION fixes for merging &gt;= 3 columns of different lengths (Tom)</para></listitem>
<listitem><para>Add DEFAULT key word to INSERT, e.g., INSERT ... (..., DEFAULT, ...) (Rod)</para></listitem>
<listitem><para>Allow views to have default values using ALTER COLUMN ... SET DEFAULT (Neil)</para></listitem>
<listitem><para>Fail on INSERTs with column lists that don't supply all column values, e.g., INSERT INTO tab (col1, col2) VALUES ('val1');  (Rod)</para></listitem>
<listitem><para>Fix for join aliases (Tom)</para></listitem>
<listitem><para>Fix for FULL OUTER JOINs (Tom)</para></listitem>
<listitem><para>Improve reporting of invalid identifier and location (Tom, Gavin)</para></listitem>
<listitem><para>Fix OPEN cursor(args) (Tom)</para></listitem>
<listitem><para>Allow 'ctid' to be used in a view and currtid(viewname) (Hiroshi)</para></listitem>
<listitem><para>Fix for CREATE TABLE AS with UNION (Tom)</para></listitem>
<listitem><para>SQL99 syntax improvements (Thomas)</para></listitem>
<listitem><para>Add statement_timeout variable to cancel queries (Bruce)</para></listitem>
<listitem><para>Allow prepared queries with PREPARE/EXECUTE (Neil)</para></listitem>
<listitem><para>Allow FOR UPDATE to appear after LIMIT/OFFSET (Bruce)</para></listitem>
<listitem><para>Add variable autocommit (Tom, David Van Wie)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Object Manipulation</title>
<itemizedlist>
<listitem><para>Make equals signs optional in CREATE DATABASE (Gavin Sherry)</para></listitem>
<listitem><para>Make ALTER TABLE OWNER change index ownership too (Neil)</para></listitem>
<listitem><para>New ALTER TABLE tabname ALTER COLUMN colname SET STORAGE controls TOAST storage, compression (John Gray)</para></listitem>
<listitem><para>Add schema support, CREATE/DROP SCHEMA (Tom)</para></listitem>
<listitem><para>Create schema for temporary tables (Tom)</para></listitem>
<listitem><para>Add variable search_path for schema search (Tom)</para></listitem>
<listitem><para>Add ALTER TABLE SET/DROP NOT NULL (Christopher)</para></listitem>
<listitem><para>New CREATE FUNCTION volatility levels (Tom)</para></listitem>
<listitem><para>Make rule names unique only per table (Tom)</para></listitem>
<listitem><para>Add 'ON tablename' clause to DROP RULE and COMMENT ON RULE (Tom)</para></listitem>
<listitem><para>Add ALTER TRIGGER RENAME (Joe)</para></listitem>
<listitem><para>New current_schema() and current_schemas() inquiry functions (Tom)</para></listitem>
<listitem><para>Allow functions to return multiple rows (table functions) (Joe)</para></listitem>
<listitem><para>Make WITH optional in CREATE DATABASE, for consistency (Bruce)</para></listitem>
<listitem><para>Add object dependency tracking (Rod, Tom)</para></listitem>
<listitem><para>Add RESTRICT/CASCADE to DROP commands (Rod)</para></listitem>
<listitem><para>Add ALTER TABLE DROP for non-CHECK CONSTRAINT (Rod)</para></listitem>
<listitem><para>Autodestroy sequence on DROP of table with SERIAL (Rod)</para></listitem>
<listitem><para>Prevent column dropping if column is used by foreign key (Rod)</para></listitem>
<listitem><para>Automatically drop constraints/functions when object is dropped (Rod)</para></listitem>
<listitem><para>Add CREATE/DROP OPERATOR CLASS (Bill Studenmund, Tom)</para></listitem>
<listitem><para>Add ALTER TABLE DROP COLUMN (Christopher, Tom, Hiroshi)</para></listitem>
<listitem><para>Prevent inherited columns from being removed or renamed (Alvaro Herrera)</para></listitem>
<listitem><para>Fix foreign key constraints to not error on intermediate database states (Stephan)</para></listitem>
<listitem><para>Propagate column or table renaming to foreign key constraints</para></listitem>
<listitem><para>Add CREATE OR REPLACE VIEW (Gavin, Neil, Tom)</para></listitem>
<listitem><para>Add CREATE OR REPLACE RULE (Gavin, Neil, Tom)</para></listitem>
<listitem><para>Have rules execute alphabetically, returning more predictable values (Tom)</para></listitem>
<listitem><para>Triggers are now fired in alphabetical order (Tom)</para></listitem>
<listitem><para>Add /contrib/adddepend to handle pre-7.3 object dependencies (Rod)</para></listitem>
<listitem><para>Allow better casting when inserting/updating values (Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Utility Commands</title>
<itemizedlist>
<listitem><para>Have COPY TO output embedded carriage returns and newlines as \r and \n (Tom)</para></listitem>
<listitem><para>Allow DELIMITER in COPY FROM to be 8-bit clean (Tatsuo)</para></listitem>
<listitem><para>Make <application>pg_dump</> use ALTER TABLE ADD PRIMARY KEY, for performance (Neil)</para></listitem>
<listitem><para>Disable brackets in multistatement rules (Bruce)</para></listitem>
<listitem><para>Disable VACUUM from being called inside a function (Bruce)</para></listitem>
<listitem><para>Allow dropdb and other scripts to use identifiers with spaces (Bruce)</para></listitem>
<listitem><para>Restrict database comment changes to the current database</para></listitem>
<listitem><para>Allow comments on operators, independent of the underlying function (Rod)</para></listitem>
<listitem><para>Rollback SET commands in aborted transactions (Tom)</para></listitem>
<listitem><para>EXPLAIN now outputs as a query (Tom)</para></listitem>
<listitem><para>Display condition expressions and sort keys in EXPLAIN (Tom)</para></listitem>
<listitem><para>Add 'SET LOCAL var = value' to set configuration variables for a single transaction (Tom)</para></listitem>
<listitem><para>Allow ANALYZE to run in a transaction (Bruce)</para></listitem>
<listitem><para>Improve COPY syntax using new WITH clauses, keep backward compatibility (Bruce)</para></listitem>
<listitem><para>Fix <application>pg_dump</> to consistently output tags in non-ASCII dumps (Bruce)</para></listitem>
<listitem><para>Make foreign key constraints clearer in dump file (Rod)</para></listitem>
<listitem><para>Add COMMENT ON CONSTRAINT (Rod)</para></listitem>
<listitem><para>Allow COPY TO/FROM to specify column names (Brent Verner)</para></listitem>
<listitem><para>Dump UNIQUE and PRIMARY KEY constraints as ALTER TABLE (Rod)</para></listitem>
<listitem><para>Have SHOW output a query result (Joe)</para></listitem>
<listitem><para>Generate failure on short COPY lines rather than pad NULLs (Neil)</para></listitem>
<listitem><para>Fix CLUSTER to preserve all table attributes (Alvaro Herrera)</para></listitem>
<listitem><para>New pg_settings table to view/modify GUC settings (Joe)</para></listitem>
<listitem><para>Add smart quoting, portability improvements to <application>pg_dump</> output (Peter)</para></listitem>
<listitem><para>Dump serial columns out as SERIAL (Tom)</para></listitem>
<listitem><para>Enable large file support, &gt;2G for <application>pg_dump</> (Peter, Philip Warner, Bruce)</para></listitem>
<listitem><para>Disallow TRUNCATE on tables that are involved in referential constraints (Rod)</para></listitem>
<listitem><para>Have TRUNCATE also auto-truncate the toast table of the relation (Tom)</para></listitem>
<listitem><para>Add clusterdb utility that will auto-cluster an entire database based on previous CLUSTER operations (Alvaro Herrera)</para></listitem>
<listitem><para>Overhaul pg_dumpall (Peter)</para></listitem>
<listitem><para>Allow REINDEX of TOAST tables (Tom)</para></listitem>
<listitem><para>Implemented START TRANSACTION, per SQL99 (Neil)</para></listitem>
<listitem><para>Fix rare index corruption when a page split affects bulk delete (Tom)</para></listitem>
<listitem><para>Fix ALTER TABLE ... ADD COLUMN for inheritance (Alvaro Herrera)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Data Types and Functions</title>
<itemizedlist>
<listitem><para>Fix factorial(0) to return 1 (Bruce)</para></listitem>
<listitem><para>Date/time/timezone improvements (Thomas)</para></listitem>
<listitem><para>Fix for array slice extraction (Tom)</para></listitem>
<listitem><para>Fix extract/date_part to report proper microseconds for timestamp (Tatsuo)</para></listitem>
<listitem><para>Allow text_substr() and bytea_substr() to read TOAST values more efficiently (John Gray)</para></listitem>
<listitem><para>Add domain support (Rod)</para></listitem>
<listitem><para>Make WITHOUT TIME ZONE the default for TIMESTAMP and TIME data types (Thomas)</para></listitem>
<listitem><para>Allow alternate storage scheme of 64-bit integers for date/time types using --enable-integer-datetimes in configure (Thomas)</para></listitem>
<listitem><para>Make timezone(timestamptz) return timestamp rather than a string (Thomas)</para></listitem>
<listitem><para>Allow fractional seconds in date/time types for dates prior to 1BC (Thomas)</para></listitem>
<listitem><para>Limit timestamp data types to 6 decimal places of precision (Thomas)</para></listitem>
<listitem><para>Change timezone conversion functions from timetz() to timezone() (Thomas)</para></listitem>
<listitem><para>Add configuration variables datestyle and timezone (Tom)</para></listitem>
<listitem><para>Add OVERLAY(), which allows substitution of a substring in a string (Thomas)</para></listitem>
<listitem><para>Add SIMILAR TO (Thomas, Tom)</para></listitem>
<listitem><para>Add regular expression SUBSTRING(string FROM pat FOR escape) (Thomas)</para></listitem>
<listitem><para>Add LOCALTIME and LOCALTIMESTAMP functions (Thomas)</para></listitem>
<listitem><para>Add named composite types using CREATE TYPE typename AS (column) (Joe)</para></listitem>
<listitem><para>Allow composite type definition in the table alias clause (Joe)</para></listitem>
<listitem><para>Add new API to simplify creation of C language table functions (Joe)</para></listitem>
<listitem><para>Remove ODBC-compatible empty parentheses from calls to SQL99 functions for which these parentheses do not match the standard (Thomas)</para></listitem>
<listitem><para>Allow macaddr data type to accept 12 hex digits with no separators (Mike Wyer)</para></listitem>
<listitem><para>Add CREATE/DROP CAST (Peter)</para></listitem>
<listitem><para>Add IS DISTINCT FROM operator (Thomas)</para></listitem>
<listitem><para>Add SQL99 TREAT() function, synonym for CAST() (Thomas)</para></listitem>
<listitem><para>Add pg_backend_pid() to output backend pid (Bruce)</para></listitem>
<listitem><para>Add IS OF / IS NOT OF type predicate (Thomas)</para></listitem>
<listitem><para>Allow bit string constants without fully-specified length (Thomas)</para></listitem>
<listitem><para>Allow conversion between 8-byte integers and bit strings (Thomas)</para></listitem>
<listitem><para>Implement hex literal conversion to bit string literal (Thomas)</para></listitem>
<listitem><para>Allow table functions to appear in the FROM clause (Joe)</para></listitem>
<listitem><para>Increase maximum number of function parameters to 32 (Bruce)</para></listitem>
<listitem><para>No longer automatically create index for SERIAL column (Tom)</para></listitem>
<listitem><para>Add current_database() (Rod)</para></listitem>
<listitem><para>Fix cash_words() to not overflow buffer (Tom)</para></listitem>
<listitem><para>Add functions replace(), split_part(), to_hex() (Joe)</para></listitem>
<listitem><para>Fix LIKE for bytea as a right-hand argument (Joe)</para></listitem>
<listitem><para>Prevent crashes caused by SELECT cash_out(2) (Tom)</para></listitem>
<listitem><para>Fix to_char(1,'FM999.99') to return a period (Karel)</para></listitem>
<listitem><para>Fix trigger/type/language functions returning OPAQUE to return proper type (Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Internationalization</title>
<itemizedlist>
<listitem><para>Add additional encodings: Korean (JOHAB), Thai (WIN874), Vietnamese (TCVN), Arabic (WIN1256), Simplified Chinese (GBK), Korean (UHC) (Eiji Tokuya)</para></listitem>
<listitem><para>Enable locale support by default (Peter)</para></listitem>
<listitem><para>Add locale variables (Peter)</para></listitem>
<listitem><para>Escape byes &gt;= 0x7f for multibyte in PQescapeBytea/PQunescapeBytea (Tatsuo)</para></listitem>
<listitem><para>Add locale awareness to regular expression character classes</para></listitem>
<listitem><para>Enable multibyte support by default (Tatsuo)</para></listitem>
<listitem><para>Add GB18030 multibyte support (Bill Huang)</para></listitem>
<listitem><para>Add CREATE/DROP CONVERSION, allowing loadable encodings (Tatsuo, Kaori)</para></listitem>
<listitem><para>Add pg_conversion table (Tatsuo)</para></listitem>
<listitem><para>Add SQL99 CONVERT() function (Tatsuo)</para></listitem>
<listitem><para>pg_dumpall, pg_controldata, and pg_resetxlog now national-language aware (Peter)</para></listitem>
<listitem><para>New and updated translations</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Server-side Languages</title>
<itemizedlist>
<listitem><para>Allow recursive SQL function (Peter)</para></listitem>
<listitem><para>Change PL/Tcl build to use configured compiler and Makefile.shlib (Peter)</para></listitem>
<listitem><para>Overhaul the PL/pgSQL FOUND variable to be more Oracle-compatible (Neil, Tom)</para></listitem>
<listitem><para>Allow PL/pgSQL to handle quoted identifiers (Tom)</para></listitem>
<listitem><para>Allow set-returning PL/pgSQL functions (Neil)</para></listitem>
<listitem><para>Make PL/pgSQL schema-aware (Joe)</para></listitem>
<listitem><para>Remove some memory leaks (Nigel J. Andrews, Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>psql</title>
<itemizedlist>
<listitem><para>Don't lowercase psql \connect database name for 7.2.0 compatibility (Tom)</para></listitem>
<listitem><para>Add psql \timing to time user queries (Greg Sabino Mullane)</para></listitem>
<listitem><para>Have psql \d show index information (Greg Sabino Mullane)</para></listitem>
<listitem><para>New psql \dD shows domains (Jonathan Eisler)</para></listitem>
<listitem><para>Allow psql to show rules on views (Paul ?)</para></listitem>
<listitem><para>Fix for psql variable substitution (Tom)</para></listitem>
<listitem><para>Allow psql \d to show temporary table structure (Tom)</para></listitem>
<listitem><para>Allow psql \d to show foreign keys (Rod)</para></listitem>
<listitem><para>Fix \? to honor \pset pager (Bruce)</para></listitem>
<listitem><para>Have psql reports its version number on startup (Tom)</para></listitem>
<listitem><para>Allow \copy to specify column names (Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>libpq</title>
<itemizedlist>
<listitem><para>Add ~/.pgpass to store host/user password combinations (Alvaro Herrera)</para></listitem>
<listitem><para>Add PQunescapeBytea() function to libpq (Patrick Welche)</para></listitem>
<listitem><para>Fix for sending large queries over non-blocking connections (Bernhard Herzog)</para></listitem>
<listitem><para>Fix for libpq using timers on Win9X (David Ford)</para></listitem>
<listitem><para>Allow libpq notify to handle servers with different-length identifiers (Tom)</para></listitem>
<listitem><para>Add libpq PQescapeString() and PQescapeBytea() to Windows (Bruce)</para></listitem>
<listitem><para>Fix for SSL with non-blocking connections (Jack Bates)</para></listitem>
<listitem><para>Add libpq connection timeout parameter (Denis A Ustimenko)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>JDBC</title>
<itemizedlist>
<listitem><para>Allow JDBC to compile with JDK 1.4 (Dave)</para></listitem>
<listitem><para>Add JDBC 3 support (Barry)</para></listitem>
<listitem><para>Allows JDBC to set loglevel by adding ?loglevel=X to the connection URL (Barry)</para></listitem>
<listitem><para>Add Driver.info() message that prints out the version number (Barry)</para></listitem>
<listitem><para>Add updateable result sets (Raghu Nidagal, Dave)</para></listitem>
<listitem><para>Add support for callable statements (Paul Bethe)</para></listitem>
<listitem><para>Add query cancel capability</para></listitem>
<listitem><para>Add refresh row (Dave)</para></listitem>
<listitem><para>Fix MD5 encryption handling for multibyte servers (Jun Kawai)</para></listitem>
<listitem><para>Add support for prepared statements (Barry)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Miscellaneous Interfaces</title>
<itemizedlist>
<listitem><para>Fixed ECPG bug concerning octal numbers in single quotes (Michael)</para></listitem>
<listitem><para>Move src/interfaces/libpgeasy to http://gborg.postgresql.org (Marc, Bruce)</para></listitem>
<listitem><para>Improve Python interface (Elliot Lee, Andrew Johnson, Greg Copeland)</para></listitem>
<listitem><para>Add libpgtcl connection close event (Gerhard Hintermayer)</para></listitem>
<listitem><para>Move src/interfaces/libpq++ to http://gborg.postgresql.org (Marc, Bruce)</para></listitem>
<listitem><para>Move src/interfaces/odbc to http://gborg.postgresql.org (Marc)</para></listitem>
<listitem><para>Move src/interfaces/libpgeasy to http://gborg.postgresql.org (Marc, Bruce)</para></listitem>
<listitem><para>Move src/interfaces/perl5 to http://gborg.postgresql.org (Marc, Bruce)</para></listitem>
<listitem><para>Remove src/bin/pgaccess from main tree, now at http://www.pgaccess.org (Bruce)</para></listitem>
<listitem><para>Add pg_on_connection_loss command to libpgtcl (Gerhard Hintermayer, Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Source Code</title>
<itemizedlist>
<listitem><para>Fix for parallel make (Peter)</para></listitem>
<listitem><para>AIX fixes for linking Tcl (Andreas Zeugswetter)</para></listitem>
<listitem><para>Allow PL/Perl to build under Cygwin (Jason Tishler)</para></listitem>
<listitem><para>Improve MIPS compiles (Peter, Oliver Elphick)</para></listitem>
<listitem><para>Require Autoconf version 2.53 (Peter)</para></listitem>
<listitem><para>Require readline and zlib by default in configure (Peter)</para></listitem>
<listitem><para>Allow Solaris to use Intimate Shared Memory (ISM), for performance (Scott Brunza, P.J. Josh Rovero)</para></listitem>
<listitem><para>Always enable syslog in compile, remove --enable-syslog option (Tatsuo)</para></listitem>
<listitem><para>Always enable multibyte in compile, remove --enable-multibyte option (Tatsuo)</para></listitem>
<listitem><para>Always enable locale in compile, remove --enable-locale option (Peter)</para></listitem>
<listitem><para>Fix for Win9x DLL creation (Magnus Naeslund)</para></listitem>
<listitem><para>Fix for link() usage by WAL code on Windows, BeOS (Jason Tishler)</para></listitem>
<listitem><para>Add sys/types.h to c.h, remove from main files (Peter, Bruce)</para></listitem>
<listitem><para>Fix AIX hang on SMP machines (Tomoyuki Niijima)</para></listitem>
<listitem><para>AIX SMP hang fix (Tomoyuki Niijima)</para></listitem>
<listitem><para>Fix pre-1970 date handling on newer glibc libraries (Tom)</para></listitem>
<listitem><para>Fix PowerPC SMP locking (Tom)</para></listitem>
<listitem><para>Prevent gcc -ffast-math from being used (Peter, Tom)</para></listitem>
<listitem><para>Bison &gt;= 1.50 now required for developer builds</para></listitem>
<listitem><para>Kerberos 5 support now builds with Heimdal (Peter)</para></listitem>
<listitem><para>Add appendix in the User's Guide which lists SQL features (Thomas)</para></listitem>
<listitem><para>Improve loadable module linking to use RTLD_NOW (Tom)</para></listitem>
<listitem><para>New error levels WARNING, INFO, LOG, DEBUG[1-5] (Bruce)</para></listitem>
<listitem><para>New src/port directory holds replaced libc functions (Peter, Bruce)</para></listitem>
<listitem><para>New pg_namespace system catalog for schemas (Tom)</para></listitem>
<listitem><para>Add pg_class.relnamespace for schemas (Tom)</para></listitem>
<listitem><para>Add pg_type.typnamespace for schemas (Tom)</para></listitem>
<listitem><para>Add pg_proc.pronamespace for schemas (Tom)</para></listitem>
<listitem><para>Restructure aggregates to have pg_proc entries (Tom)</para></listitem>
<listitem><para>System relations now have their own namespace, pg_* test not required (Fernando Nasser)</para></listitem>
<listitem><para>Rename TOAST index names to be *_index rather than *_idx (Neil)</para></listitem>
<listitem><para>Add namespaces for operators, opclasses (Tom)</para></listitem>
<listitem><para>Add additional checks to server control file (Thomas)</para></listitem>
<listitem><para>New Polish FAQ (Marcin Mazurek)</para></listitem>
<listitem><para>Add Posix semaphore support (Tom)</para></listitem>
<listitem><para>Document need for reindex (Bruce)</para></listitem>
<listitem><para>Rename some internal identifiers to simplify Windows compile (Jan, Katherine Ward)</para></listitem>
<listitem><para>Add documentation on computing disk space (Bruce)</para></listitem>
<listitem><para>Remove KSQO from GUC (Bruce)</para></listitem>
<listitem><para>Fix memory leak in rtree (Kenneth Been)</para></listitem>
<listitem><para>Modify a few error messages for consistency (Bruce)</para></listitem>
<listitem><para>Remove unused system table columns (Peter)</para></listitem>
<listitem><para>Make system columns NOT NULL where appropriate (Tom)</para></listitem>
<listitem><para>Clean up use of sprintf in favor of snprintf() (Neil, Jukka Holappa)</para></listitem>
<listitem><para>Remove OPAQUE and create specific subtypes (Tom)</para></listitem>
<listitem><para>Cleanups in array internal handling (Joe, Tom)</para></listitem>
<listitem><para>Disallow pg_atoi('') (Bruce)</para></listitem>
<listitem><para>Remove parameter wal_files because WAL files are now recycled (Bruce)</para></listitem>
<listitem><para>Add version numbers to heap pages (Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Contrib</title>
<itemizedlist>
<listitem><para>Allow inet arrays in /contrib/array (Neil)</para></listitem>
<listitem><para>GiST fixes (Teodor Sigaev, Neil)</para></listitem>
<listitem><para>Upgrade /contrib/mysql</para></listitem>
<listitem><para>Add /contrib/dbsize which shows table sizes without vacuum (Peter)</para></listitem>
<listitem><para>Add /contrib/intagg, integer aggregator routines (mlw)</para></listitem>
<listitem><para>Improve /contrib/oid2name (Neil, Bruce)</para></listitem>
<listitem><para>Improve /contrib/tsearch (Oleg, Teodor Sigaev)</para></listitem>
<listitem><para>Cleanups of /contrib/rserver (Alexey V. Borzov)</para></listitem>
<listitem><para>Update /contrib/oracle conversion utility (Gilles Darold)</para></listitem>
<listitem><para>Update /contrib/dblink (Joe)</para></listitem>
<listitem><para>Improve options supported by /contrib/vacuumlo (Mario Weilguni)</para></listitem>
<listitem><para>Improvements to /contrib/intarray (Oleg, Teodor Sigaev, Andrey Oktyabrski)</para></listitem>
<listitem><para>Add /contrib/reindexdb utility (Shaun Thomas)</para></listitem>
<listitem><para>Add indexing to /contrib/isbn_issn (Dan Weston)</para></listitem>
<listitem><para>Add /contrib/dbmirror (Steven Singer)</para></listitem>
<listitem><para>Improve /contrib/pgbench (Neil)</para></listitem>
<listitem><para>Add /contrib/tablefunc table function examples (Joe)</para></listitem>
<listitem><para>Add /contrib/ltree data type for tree structures (Teodor Sigaev, Oleg Bartunov)</para></listitem>
<listitem><para>Move /contrib/pg_controldata, pg_resetxlog into main tree (Bruce)</para></listitem>
<listitem><para>Fixes to /contrib/cube (Bruno Wolff)</para></listitem>
<listitem><para>Improve /contrib/fulltextindex (Christopher)</para></listitem>
</itemizedlist>
  </sect3>

 </sect2>
</sect1>

 <sect1 id="release-7-2-8">
  <title>Release 7.2.8</title>

  <note>
  <title>Release date</title>
  <simpara>2005-05-09</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.2.7, including one
   security-related issue.
  </para>

  <sect2>
   <title>Migration to Version 7.2.8</title>

   <para>
    A dump/restore is not required for those running 7.2.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Repair ancient race condition that allowed a transaction to be
seen as committed for some purposes (eg SELECT FOR UPDATE) slightly sooner
than for other purposes</para>
<para>This is an extremely serious bug since it could lead to apparent
data inconsistencies being briefly visible to applications.</para></listitem>
<listitem><para>Repair race condition between relation extension and
VACUUM</para>
<para>This could theoretically have caused loss of a page's worth of
freshly-inserted data, although the scenario seems of very low probability.
There are no known cases of it having caused more than an Assert failure.
</para></listitem>
<listitem><para>Fix <function>EXTRACT(EPOCH)</> for
<type>TIME WITH TIME ZONE</> values</para></listitem>
<listitem><para>Additional buffer overrun checks in plpgsql
(Neil)</para></listitem>
<listitem><para>Fix pg_dump to dump index names and trigger names containing
<literal>%</> correctly (Neil)</para></listitem>
<listitem><para>Prevent <function>to_char(interval)</> from dumping core for
month-related formats</para></listitem>
<listitem><para>Fix <filename>contrib/pgcrypto</> for newer OpenSSL builds
(Marko Kreen)</para></listitem>
</itemizedlist>

 </sect2>
</sect1>

 <sect1 id="release-7-2-7">
  <title>Release 7.2.7</title>

  <note>
  <title>Release date</title>
  <simpara>2005-01-31</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.2.6, including several
   security-related issues.
  </para>

  <sect2>
   <title>Migration to Version 7.2.7</title>

   <para>
    A dump/restore is not required for those running 7.2.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Disallow <command>LOAD</> to non-superusers</para>
<para>
On platforms that will automatically execute initialization functions of a
shared library (this includes at least Windows and ELF-based Unixen),
<command>LOAD</> can be used to make the server execute arbitrary code.
Thanks to NGS Software for reporting this.</para></listitem>
<listitem><para>Add needed STRICT marking to some contrib functions (Kris
Jurka)</para></listitem>
<listitem><para>Avoid buffer overrun when plpgsql cursor declaration has too
many parameters (Neil)</para></listitem>
<listitem><para>Fix planning error for FULL and RIGHT outer joins</para>
<para>
The result of the join was mistakenly supposed to be sorted the same as the
left input.  This could not only deliver mis-sorted output to the user, but
in case of nested merge joins could give outright wrong answers.
</para></listitem>
<listitem><para>Fix display of negative intervals in SQL and GERMAN
datestyles</para></listitem>
</itemizedlist>

 </sect2>
</sect1>

 <sect1 id="release-7-2-6">
  <title>Release 7.2.6</title>

  <note>
  <title>Release date</title>
  <simpara>2004-10-22</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.2.5.
  </para>


  <sect2>
   <title>Migration to Version 7.2.6</title>

   <para>
    A dump/restore is not required for those running 7.2.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Repair possible failure to update hint bits on disk</para>
<para>
Under rare circumstances this oversight could lead to
<quote>could not access transaction status</> failures, which qualifies
it as a potential-data-loss bug.
</para></listitem>
<listitem><para>Ensure that hashed outer join does not miss tuples</para>
<para>
Very large left joins using a hash join plan could fail to output unmatched
left-side rows given just the right data distribution.
</para></listitem>
<listitem><para>Disallow running pg_ctl as root</para>
<para>
This is to guard against any possible security issues.
</para></listitem>
<listitem><para>Avoid using temp files in /tmp in make_oidjoins_check</para>
<para>
This has been reported as a security issue, though it's hardly worthy of
concern since there is no reason for non-developers to use this script anyway.
</para></listitem>
<listitem><para>Update to newer versions of Bison</para></listitem>
</itemizedlist>

 </sect2>
</sect1>

 <sect1 id="release-7-2-5">
  <title>Release 7.2.5</title>

  <note>
  <title>Release date</title>
  <simpara>2004-08-16</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 7.2.4.
  </para>


  <sect2>
   <title>Migration to Version 7.2.5</title>

   <para>
    A dump/restore is not required for those running 7.2.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

<itemizedlist>
<listitem><para>Prevent possible loss of committed transactions during crash</para>
<para>
Due to insufficient interlocking between transaction commit and checkpointing,
it was possible for transactions committed just before the most recent
checkpoint to be lost, in whole or in part, following a database crash and
restart.  This is a serious bug that has existed
since <productname>PostgreSQL</productname> 7.1.
</para></listitem>
<listitem><para>Fix corner case for btree search in parallel with first root page split</para></listitem>
<listitem><para>Fix buffer overrun in <function>to_ascii</function> (Guido Notari)</para></listitem>
<listitem><para>Fix core dump in deadlock detection on machines where char is unsigned</para></listitem>
<listitem><para>Fix failure to respond to <command>pg_ctl stop -m fast</command> after Async_NotifyHandler runs</para></listitem>
<listitem><para>Repair memory leaks in pg_dump</para></listitem>
<listitem><para>Avoid conflict with system definition of <function>isblank()</function> function or macro</para></listitem>
</itemizedlist>
 </sect2>
</sect1>

<sect1 id="release-7-2-4">
 <title>Release 7.2.4</title>

 <note>
  <title>Release date</title>
  <simpara>2003-01-30</simpara>
 </note>

 <para>
  This release contains a variety of fixes for version 7.2.3,
  including fixes to prevent possible data loss.
 </para>

 <sect2>
  <title>Migration to Version 7.2.4</title>

  <para>
   A dump/restore is <emphasis>not</emphasis> required for those
   running version 7.2.*.
  </para>
 </sect2>

 <sect2>
  <title>Changes</title>

<itemizedlist>
<listitem><para>Fix some additional cases of VACUUM "No one parent tuple was found" error</para></listitem>
<listitem><para>Prevent VACUUM from being called inside a function  (Bruce)</para></listitem>
<listitem><para>Ensure pg_clog updates are sync'd to disk before marking checkpoint complete</para></listitem>
<listitem><para>Avoid integer overflow during large hash joins</para></listitem>
<listitem><para>Make GROUP commands work when pg_group.grolist is large enough to be toasted</para></listitem>
<listitem><para>Fix errors in datetime tables; some timezone names weren't being recognized</para></listitem>
<listitem><para>Fix integer overflows in circle_poly(), path_encode(), path_add()  (Neil)</para></listitem>
<listitem><para>Repair long-standing logic errors in lseg_eq(), lseg_ne(), lseg_center()</para></listitem>
</itemizedlist>
 </sect2>
</sect1>


<sect1 id="release-7-2-3">
 <title>Release 7.2.3</title>

 <note>
  <title>Release date</title>
  <simpara>2002-10-01</simpara>
 </note>

 <para>
  This release contains a variety of fixes for version 7.2.2,
  including fixes to prevent possible data loss.
 </para>

 <sect2>
  <title>Migration to Version 7.2.3</title>

  <para>
   A dump/restore is <emphasis>not</emphasis> required for those
   running version 7.2.*.
  </para>
 </sect2>

 <sect2>
  <title>Changes</title>

<itemizedlist>
<listitem><para>Prevent possible compressed transaction log loss (Tom)</para></listitem>
<listitem><para>Prevent non-superuser from increasing most recent vacuum info (Tom)</para></listitem>
<listitem><para>Handle pre-1970 date values in newer versions of glibc (Tom)</para></listitem>
<listitem><para>Fix possible hang during server shutdown</para></listitem>
<listitem><para>Prevent spinlock hangs on SMP PPC machines (Tomoyuki Niijima)</para></listitem>
<listitem><para>Fix <application>pg_dump</> to properly dump FULL JOIN USING (Tom)</para></listitem>
</itemizedlist>
 </sect2>
</sect1>


<sect1 id="release-7-2-2">
 <title>Release 7.2.2</title>

 <note>
  <title>Release date</title>
  <simpara>2002-08-23</simpara>
 </note>

 <para>
  This release contains a variety of fixes for version 7.2.1.
 </para>

 <sect2>
  <title>Migration to Version 7.2.2</title>

  <para>
   A dump/restore is <emphasis>not</emphasis> required for those
   running version 7.2.*.
  </para>
 </sect2>

 <sect2>
  <title>Changes</title>

<itemizedlist>
<listitem><para>Allow EXECUTE of "CREATE TABLE AS ... SELECT" in PL/pgSQL (Tom)</para></listitem>
<listitem><para>Fix for compressed transaction log id wraparound (Tom)</para></listitem>
<listitem><para>Fix PQescapeBytea/PQunescapeBytea so that they handle bytes &gt; 0x7f (Tatsuo)</para></listitem>
<listitem><para>Fix for psql and <application>pg_dump</> crashing when invoked with non-existent long options (Tatsuo)</para></listitem>
<listitem><para>Fix crash when invoking geometric operators (Tom)</para></listitem>
<listitem><para>Allow OPEN cursor(args) (Tom)</para></listitem>
<listitem><para>Fix for rtree_gist index build (Teodor)</para></listitem>
<listitem><para>Fix for dumping user-defined aggregates (Tom)</para></listitem>
<listitem><para>contrib/intarray fixes (Oleg)</para></listitem>
<listitem><para>Fix for complex UNION/EXCEPT/INTERSECT queries using parens (Tom)</para></listitem>
<listitem><para>Fix to pg_convert (Tatsuo)</para></listitem>
<listitem><para>Fix for crash with long DATA strings (Thomas, Neil)</para></listitem>
<listitem><para>Fix for repeat(), lpad(), rpad() and long strings (Neil)</para></listitem>
</itemizedlist>
 </sect2>
</sect1>


<sect1 id="release-7-2-1">
 <title>Release 7.2.1</title>

 <note>
  <title>Release date</title>
  <simpara>2002-03-21</simpara>
 </note>

 <para>
  This release contains a variety of fixes for version 7.2.
 </para>

 <sect2>
  <title>Migration to Version 7.2.1</title>

  <para>
   A dump/restore is <emphasis>not</emphasis> required for those
   running version 7.2.
  </para>
 </sect2>

 <sect2>
  <title>Changes</title>

<itemizedlist>
<listitem><para>Ensure that sequence counters do not go backwards after a crash (Tom)</para></listitem>
<listitem><para>Fix pgaccess kanji-conversion key binding (Tatsuo)</para></listitem>
<listitem><para>Optimizer improvements (Tom)</para></listitem>
<listitem><para>Cash I/O improvements (Tom)</para></listitem>
<listitem><para>New Russian FAQ</para></listitem>
<listitem><para>Compile fix for missing AuthBlockSig (Heiko)</para></listitem>
<listitem><para>Additional time zones and time zone fixes (Thomas)</para></listitem>
<listitem><para>Allow psql \connect to handle mixed case database and user names (Tom)</para></listitem>
<listitem><para>Return proper OID on command completion even with ON INSERT rules (Tom)</para></listitem>
<listitem><para>Allow COPY FROM to use 8-bit DELIMITERS (Tatsuo)</para></listitem>
<listitem><para>Fix bug in extract/date_part for milliseconds/microseconds (Tatsuo)</para></listitem>
<listitem><para>Improve handling of multiple UNIONs with different lengths (Tom)</para></listitem>
<listitem><para>contrib/btree_gist improvements (Teodor Sigaev)</para></listitem>
<listitem><para>contrib/tsearch dictionary improvements, see README.tsearch for an additional installation step (Thomas T. Thai, Teodor Sigaev)</para></listitem>
<listitem><para>Fix for array subscripts handling (Tom)</para></listitem>
<listitem><para>Allow EXECUTE of "CREATE TABLE AS ... SELECT" in PL/pgSQL (Tom)</para></listitem>
</itemizedlist>
 </sect2>
</sect1>


<sect1 id="release-7-2">
 <title>Release 7.2</title>

 <note>
  <title>Release date</title>
  <simpara>2002-02-04</simpara>
 </note>

 <sect2>
  <title>Overview</title>

  <para>
   This release improves <productname>PostgreSQL</> for use in
   high-volume applications.
  </para>

  <para>
   Major changes in this release:
  </para>

  <variablelist>
   <varlistentry>
    <term>VACUUM</term>
    <listitem>
     <para>
      Vacuuming no longer locks tables, thus allowing normal user
      access during the vacuum.  A new <command>VACUUM FULL</>
      command does old-style vacuum by locking the table and
      shrinking the on-disk copy of the table.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Transactions</term>
    <listitem>
     <para>
      There is no longer a problem with installations that exceed
      four billion transactions.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>OIDs</term>
    <listitem>
     <para>
      OIDs are now optional.  Users can now create tables without
      OIDs for cases where OID usage is excessive.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Optimizer</term>
    <listitem>
     <para>
      The system now computes histogram column statistics during
      <command>ANALYZE</>, allowing much better optimizer choices.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Security</term>
    <listitem>
     <para>
      A new MD5 encryption option allows more secure storage and
      transfer of passwords.  A new Unix-domain socket
      authentication option is available on Linux and BSD systems.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Statistics</term>
    <listitem>
     <para>
      Administrators can use the new table access statistics module
      to get fine-grained information about table and index usage.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>Internationalization</term>
    <listitem>
     <para>
      Program and library messages can now be displayed in several
      languages.
     </para>
    </listitem>
   </varlistentry>

  </variablelist>
 </sect2>

 <sect2>
  <title>Migration to Version 7.2</title>

  <para>
   A dump/restore using <command>pg_dump</command> is required for
   those wishing to migrate data from any previous release.
  </para>

  <para>
   Observe the following incompatibilities:
  </para>

  <itemizedlist>
   <listitem>
    <para>
     The semantics of the <command>VACUUM</command> command have
     changed in this release.  You might wish to update your
     maintenance procedures accordingly.
    </para>
   </listitem>

   <listitem>
    <para>
     In this release, comparisons using <literal>= NULL</literal>
     will always return false (or NULL, more precisely).  Previous
     releases automatically transformed this syntax to <literal>IS
     NULL</literal>.  The old behavior can be re-enabled using a
     <filename>postgresql.conf</filename> parameter.
    </para>
   </listitem>

   <listitem>
    <para>
     The <filename>pg_hba.conf</> and <filename>pg_ident.conf</>
     configuration is now only reloaded after receiving a
     <systemitem>SIGHUP</> signal, not with each connection.
    </para>
   </listitem>

   <listitem>
    <para>
     The function <filename>octet_length()</> now returns the uncompressed data length.
    </para>
   </listitem>

   <listitem>
    <para>
     The date/time value <literal>'current'</literal> is no longer
     available.  You will need to rewrite your applications.
    </para>
   </listitem>

   <listitem>
    <para>
     The <literal>timestamp()</literal>, <literal>time()</literal>,
     and <literal>interval()</literal> functions are no longer
     available.  Instead of <literal>timestamp()</literal>, use
     <literal>timestamp 'string'</literal> or <literal>CAST</literal>.
    </para>
   </listitem>

  </itemizedlist>

  <para>
   The <literal>SELECT ... LIMIT #,#</literal> syntax will be removed
   in the next release. You should change your queries to use
   separate LIMIT and OFFSET clauses, e.g. <literal>LIMIT 10 OFFSET
   20</literal>.
  </para>
 </sect2>

 <sect2>
  <title>Changes</title>

  <sect3>
   <title>Server Operation</title>
<itemizedlist>
<listitem><para>Create temporary files in a separate directory (Bruce)</para></listitem>
<listitem><para>Delete orphaned temporary files on postmaster startup (Bruce)</para></listitem>
<listitem><para>Added unique indexes to some system tables (Tom)</para></listitem>
<listitem><para>System table operator reorganization (Oleg Bartunov, Teodor Sigaev, Tom)</para></listitem>
<listitem><para>Renamed pg_log to pg_clog (Tom)</para></listitem>
<listitem><para>Enable SIGTERM, SIGQUIT to kill backends (Jan)</para></listitem>
<listitem><para>Removed compile-time limit on number of backends (Tom)</para></listitem>
<listitem><para>Better cleanup for semaphore resource failure (Tatsuo, Tom)</para></listitem>
<listitem><para>Allow safe transaction ID wraparound (Tom)</para></listitem>
<listitem><para>Removed OIDs from some system tables (Tom)</para></listitem>
<listitem><para>Removed "triggered data change violation" error check (Tom)</para></listitem>
<listitem><para>SPI portal creation of prepared/saved plans (Jan)</para></listitem>
<listitem><para>Allow SPI column functions to work for system columns (Tom)</para></listitem>
<listitem><para>Long value compression improvement (Tom)</para></listitem>
<listitem><para>Statistics collector for table, index access (Jan)</para></listitem>
<listitem><para>Truncate extra-long sequence names to a reasonable value (Tom)</para></listitem>
<listitem><para>Measure transaction times in milliseconds (Thomas)</para></listitem>
<listitem><para>Fix TID sequential scans (Hiroshi)</para></listitem>
<listitem><para>Superuser ID now fixed at 1 (Peter E)</para></listitem>
<listitem><para>New pg_ctl "reload" option (Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Performance</title>
<itemizedlist>
<listitem><para>Optimizer improvements (Tom)</para></listitem>
<listitem><para>New histogram column statistics for optimizer (Tom)</para></listitem>
<listitem><para>Reuse write-ahead log files rather than discarding them (Tom)</para></listitem>
<listitem><para>Cache improvements (Tom)</para></listitem>
<listitem><para>IS NULL, IS NOT NULL optimizer improvement (Tom)</para></listitem>
<listitem><para>Improve lock manager to reduce lock contention (Tom)</para></listitem>
<listitem><para>Keep relcache entries for index access support functions (Tom)</para></listitem>
<listitem><para>Allow better selectivity with NaN and infinities in NUMERIC (Tom)</para></listitem>
<listitem><para>R-tree performance improvements (Kenneth Been)</para></listitem>
<listitem><para>B-tree splits more efficient (Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Privileges</title>
<itemizedlist>
<listitem><para>Change UPDATE, DELETE privileges to be distinct (Peter E)</para></listitem>
<listitem><para>New REFERENCES, TRIGGER privileges (Peter E)</para></listitem>
<listitem><para>Allow GRANT/REVOKE to/from more than one user at a time (Peter E)</para></listitem>
<listitem><para>New has_table_privilege() function (Joe Conway)</para></listitem>
<listitem><para>Allow non-superuser to vacuum database (Tom)</para></listitem>
<listitem><para>New SET SESSION AUTHORIZATION command (Peter E)</para></listitem>
<listitem><para>Fix bug in privilege modifications on newly created tables (Tom)</para></listitem>
<listitem><para>Disallow access to pg_statistic for non-superuser, add user-accessible views (Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Client Authentication</title>
<itemizedlist>
<listitem><para>Fork postmaster before doing authentication to prevent hangs (Peter E)</para></listitem>
<listitem><para>Add ident authentication over Unix domain sockets on Linux, *BSD (Helge Bahmann, Oliver Elphick, Teodor Sigaev, Bruce)</para></listitem>
<listitem><para>Add a password authentication method that uses MD5 encryption (Bruce)</para></listitem>
<listitem><para>Allow encryption of stored passwords using MD5 (Bruce)</para></listitem>
<listitem><para>PAM authentication (Dominic J. Eidson)</para></listitem>
<listitem><para>Load pg_hba.conf and pg_ident.conf only on startup and SIGHUP (Bruce)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Server Configuration</title>
<itemizedlist>
<listitem><para>Interpretation of some time zone abbreviations as Australian rather than North American now settable at run time (Bruce)</para></listitem>
<listitem><para>New parameter to set default transaction isolation level (Peter E)</para></listitem>
<listitem><para>New parameter to enable conversion of "expr = NULL" into "expr IS NULL", off by default (Peter E)</para></listitem>
<listitem><para>New parameter to control memory usage by VACUUM (Tom)</para></listitem>
<listitem><para>New parameter to set client authentication timeout (Tom)</para></listitem>
<listitem><para>New parameter to set maximum number of open files (Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Queries</title>
<itemizedlist>
<listitem><para>Statements added by INSERT rules now execute after the INSERT (Jan)</para></listitem>
<listitem><para>Prevent unadorned relation names in target list (Bruce)</para></listitem>
<listitem><para>NULLs now sort after all normal values in ORDER BY (Tom)</para></listitem>
<listitem><para>New IS UNKNOWN, IS NOT UNKNOWN Boolean tests (Tom)</para></listitem>
<listitem><para>New SHARE UPDATE EXCLUSIVE lock mode (Tom)</para></listitem>
<listitem><para>New EXPLAIN ANALYZE command that shows run times and row counts (Martijn van Oosterhout)</para></listitem>
<listitem><para>Fix problem with LIMIT and subqueries (Tom)</para></listitem>
<listitem><para>Fix for LIMIT, DISTINCT ON pushed into subqueries (Tom)</para></listitem>
<listitem><para>Fix nested EXCEPT/INTERSECT (Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Schema Manipulation</title>
<itemizedlist>
<listitem><para>Fix SERIAL in temporary tables (Bruce)</para></listitem>
<listitem><para>Allow temporary sequences (Bruce)</para></listitem>
<listitem><para>Sequences now use int8 internally (Tom)</para></listitem>
<listitem><para>New SERIAL8 creates int8 columns with sequences, default still SERIAL4 (Tom)</para></listitem>
<listitem><para>Make OIDs optional using WITHOUT OIDS (Tom)</para></listitem>
<listitem><para>Add %TYPE syntax to CREATE TYPE (Ian Lance Taylor)</para></listitem>
<listitem><para>Add ALTER TABLE / DROP CONSTRAINT for CHECK constraints (Christopher Kings-Lynne)</para></listitem>
<listitem><para>New CREATE OR REPLACE FUNCTION to alter existing function (preserving the function OID) (Gavin Sherry)</para></listitem>
<listitem><para>Add ALTER TABLE / ADD [ UNIQUE | PRIMARY ] (Christopher Kings-Lynne)</para></listitem>
<listitem><para>Allow column renaming in views</para></listitem>
<listitem><para>Make ALTER TABLE / RENAME COLUMN update column names of indexes (Brent Verner)</para></listitem>
<listitem><para>Fix for ALTER TABLE / ADD CONSTRAINT ... CHECK with inherited tables (Stephan Szabo)</para></listitem>
<listitem><para>ALTER TABLE RENAME update foreign-key trigger arguments correctly (Brent Verner)</para></listitem>
<listitem><para>DROP AGGREGATE and COMMENT ON AGGREGATE now accept an aggtype (Tom)</para></listitem>
<listitem><para>Add automatic return type data casting for SQL functions (Tom)</para></listitem>
<listitem><para>Allow GiST indexes to handle NULLs and multikey indexes (Oleg Bartunov, Teodor Sigaev, Tom)</para></listitem>
<listitem><para>Enable partial indexes (Martijn van Oosterhout)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Utility Commands</title>
<itemizedlist>
<listitem><para>Add RESET ALL, SHOW ALL (Marko Kreen)</para></listitem>
<listitem><para>CREATE/ALTER USER/GROUP now allow options in any order (Vince)</para></listitem>
<listitem><para>Add LOCK A, B, C functionality (Neil Padgett)</para></listitem>
<listitem><para>New ENCRYPTED/UNENCRYPTED option to CREATE/ALTER USER (Bruce)</para></listitem>
<listitem><para>New light-weight VACUUM does not lock table; old semantics are available as VACUUM FULL (Tom)</para></listitem>
<listitem><para>Disable COPY TO/FROM on views (Bruce)</para></listitem>
<listitem><para>COPY DELIMITERS string must be exactly one character (Tom)</para></listitem>
<listitem><para>VACUUM warning about index tuples fewer than heap now only appears when appropriate (Martijn van Oosterhout)</para></listitem>
<listitem><para>Fix privilege checks for CREATE INDEX (Tom)</para></listitem>
<listitem><para>Disallow inappropriate use of CREATE/DROP INDEX/TRIGGER/VIEW (Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Data Types and Functions</title>
<itemizedlist>
<listitem><para>SUM(), AVG(), COUNT() now uses int8 internally for speed (Tom)</para></listitem>
<listitem><para>Add convert(), convert2() (Tatsuo)</para></listitem>
<listitem><para>New function bit_length() (Peter E)</para></listitem>
<listitem><para>Make the "n" in CHAR(n)/VARCHAR(n) represents letters, not bytes (Tatsuo)</para></listitem>
<listitem><para>CHAR(), VARCHAR() now reject strings that are too long (Peter E)</para></listitem>
<listitem><para>BIT VARYING now rejects bit strings that are too long (Peter E)</para></listitem>
<listitem><para>BIT now rejects bit strings that do not match declared size (Peter E)</para></listitem>
<listitem><para>INET, CIDR text conversion functions (Alex Pilosov)</para></listitem>
<listitem><para>INET, CIDR operators &lt;&lt; and &lt;&lt;= indexable (Alex Pilosov)</para></listitem>
<listitem><para>Bytea \### now requires valid three digit octal number</para></listitem>
<listitem><para>Bytea comparison improvements, now supports =, &lt;&gt;, &gt;, &gt;=, &lt;, and &lt;=</para></listitem>
<listitem><para>Bytea now supports B-tree indexes</para></listitem>
<listitem><para>Bytea now supports LIKE, LIKE...ESCAPE, NOT LIKE, NOT LIKE...ESCAPE</para></listitem>
<listitem><para>Bytea now supports concatenation</para></listitem>
<listitem><para>New bytea functions: position, substring, trim, btrim, and length</para></listitem>
<listitem><para>New encode() function mode, "escaped", converts minimally escaped bytea to/from text</para></listitem>
<listitem><para>Add pg_database_encoding_max_length() (Tatsuo)</para></listitem>
<listitem><para>Add pg_client_encoding() function (Tatsuo)</para></listitem>
<listitem><para>now() returns time with millisecond precision (Thomas)</para></listitem>
<listitem><para>New TIMESTAMP WITHOUT TIMEZONE data type (Thomas)</para></listitem>
<listitem><para>Add ISO date/time specification with "T", yyyy-mm-ddThh:mm:ss (Thomas)</para></listitem>
<listitem><para>New xid/int comparison functions (Hiroshi)</para></listitem>
<listitem><para>Add precision to TIME, TIMESTAMP, and INTERVAL data types (Thomas)</para></listitem>
<listitem><para>Modify type coercion logic to attempt binary-compatible functions first (Tom)</para></listitem>
<listitem><para>New encode() function installed by default (Marko Kreen)</para></listitem>
<listitem><para>Improved to_*() conversion functions (Karel Zak)</para></listitem>
<listitem><para>Optimize LIKE/ILIKE when using single-byte encodings (Tatsuo)</para></listitem>
<listitem><para>New functions in contrib/pgcrypto: crypt(), hmac(), encrypt(), gen_salt() (Marko Kreen)</para></listitem>
<listitem><para>Correct description of translate() function (Bruce)</para></listitem>
<listitem><para>Add INTERVAL argument for SET TIME ZONE (Thomas)</para></listitem>
<listitem><para>Add INTERVAL YEAR TO MONTH (etc.) syntax (Thomas)</para></listitem>
<listitem><para>Optimize length functions when using single-byte encodings (Tatsuo)</para></listitem>
<listitem><para>Fix path_inter, path_distance, path_length, dist_ppath to handle closed paths (Curtis Barrett, Tom)</para></listitem>
<listitem><para>octet_length(text) now returns non-compressed length (Tatsuo, Bruce)</para></listitem>
<listitem><para>Handle "July" full name in date/time literals (Greg Sabino Mullane)</para></listitem>
<listitem><para>Some datatype() function calls now evaluated differently</para></listitem>
<listitem><para>Add support for Julian and ISO time specifications (Thomas)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Internationalization</title>
<itemizedlist>
<listitem><para>National language support in psql, <application>pg_dump</>, libpq, and server (Peter E)</para></listitem>
<listitem><para>Message translations in Chinese (simplified, traditional), Czech, French, German, Hungarian, Russian, Swedish (Peter E, Serguei A. Mokhov, Karel Zak, Weiping He, Zhenbang Wei, Kovacs Zoltan)</para></listitem>
<listitem><para>Make trim, ltrim, rtrim, btrim, lpad, rpad, translate multibyte aware (Tatsuo)</para></listitem>
<listitem><para>Add LATIN5,6,7,8,9,10 support (Tatsuo)</para></listitem>
<listitem><para>Add ISO 8859-5,6,7,8 support (Tatsuo)</para></listitem>
<listitem><para>Correct LATIN5 to mean ISO-8859-9, not ISO-8859-5 (Tatsuo)</para></listitem>
<listitem><para>Make mic2ascii() non-ASCII aware (Tatsuo)</para></listitem>
<listitem><para>Reject invalid multibyte character sequences (Tatsuo)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title><application>PL/pgSQL</></title>
<itemizedlist>
<listitem><para>Now uses portals for SELECT loops, allowing huge result sets (Jan)</para></listitem>
<listitem><para>CURSOR and REFCURSOR support (Jan)</para></listitem>
<listitem><para>Can now return open cursors (Jan)</para></listitem>
<listitem><para>Add ELSEIF (Klaus Reger)</para></listitem>
<listitem><para>Improve PL/pgSQL error reporting, including location of error (Tom)</para></listitem>
<listitem><para>Allow IS or FOR key words in cursor declaration, for compatibility (Bruce)</para></listitem>
<listitem><para>Fix for SELECT ... FOR UPDATE (Tom)</para></listitem>
<listitem><para>Fix for PERFORM returning multiple rows (Tom)</para></listitem>
<listitem><para>Make PL/pgSQL use the server's type coercion code (Tom)</para></listitem>
<listitem><para>Memory leak fix (Jan, Tom)</para></listitem>
<listitem><para>Make trailing semicolon optional (Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>PL/Perl</title>
<itemizedlist>
<listitem><para>New untrusted PL/Perl (Alex Pilosov)</para></listitem>
<listitem><para>PL/Perl is now built on some platforms even if libperl is not shared (Peter E)</para></listitem>
</itemizedlist>
   </sect3>

  <sect3>
   <title>PL/Tcl</title>
<itemizedlist>
<listitem><para>Now reports errorInfo (Vsevolod Lobko)</para></listitem>
<listitem><para>Add spi_lastoid function (bob@redivi.com)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>PL/Python</title>
<itemizedlist>
<listitem><para>...is new (Andrew Bosma)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title><application>psql</></title>
<itemizedlist>
<listitem><para>\d displays indexes in unique, primary groupings (Christopher Kings-Lynne)</para></listitem>
<listitem><para>Allow trailing semicolons in backslash commands (Greg Sabino Mullane)</para></listitem>
<listitem><para>Read password from /dev/tty if possible</para></listitem>
<listitem><para>Force new password prompt when changing user and database (Tatsuo, Tom)</para></listitem>
<listitem><para>Format the correct number of columns for Unicode (Patrice)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title><application>libpq</></title>
<itemizedlist>
<listitem><para>New function PQescapeString() to escape quotes in command strings (Florian Weimer)</para></listitem>
<listitem><para>New function PQescapeBytea() escapes binary strings for use as SQL string literals</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>JDBC</title>
<itemizedlist>
<listitem><para>Return OID of INSERT (Ken K)</para></listitem>
<listitem><para>Handle more data types (Ken K)</para></listitem>
<listitem><para>Handle single quotes and newlines in strings (Ken K)</para></listitem>
<listitem><para>Handle NULL variables (Ken K)</para></listitem>
<listitem><para>Fix for time zone handling (Barry Lind)</para></listitem>
<listitem><para>Improved Druid support</para></listitem>
<listitem><para>Allow eight-bit characters with non-multibyte server (Barry Lind)</para></listitem>
<listitem><para>Support BIT, BINARY types (Ned Wolpert)</para></listitem>
<listitem><para>Reduce memory usage (Michael Stephens, Dave Cramer)</para></listitem>
<listitem><para>Update DatabaseMetaData (Peter E)</para></listitem>
<listitem><para>Add DatabaseMetaData.getCatalogs() (Peter E)</para></listitem>
<listitem><para>Encoding fixes (Anders Bengtsson)</para></listitem>
<listitem><para>Get/setCatalog methods (Jason Davies)</para></listitem>
<listitem><para>DatabaseMetaData.getColumns() now returns column defaults (Jason Davies)</para></listitem>
<listitem><para>DatabaseMetaData.getColumns() performance improvement (Jeroen van Vianen)</para></listitem>
<listitem><para>Some JDBC1 and JDBC2 merging (Anders Bengtsson)</para></listitem>
<listitem><para>Transaction performance improvements (Barry Lind)</para></listitem>
<listitem><para>Array fixes (Greg Zoller)</para></listitem>
<listitem><para>Serialize addition </para></listitem>
<listitem><para>Fix batch processing (Rene Pijlman)</para></listitem>
<listitem><para>ExecSQL method reorganization (Anders Bengtsson)</para></listitem>
<listitem><para>GetColumn() fixes (Jeroen van Vianen)</para></listitem>
<listitem><para>Fix isWriteable() function (Rene Pijlman)</para></listitem>
<listitem><para>Improved passage of JDBC2 conformance tests (Rene Pijlman)</para></listitem>
<listitem><para>Add bytea type capability (Barry Lind)</para></listitem>
<listitem><para>Add isNullable() (Rene Pijlman)</para></listitem>
<listitem><para>JDBC date/time test suite fixes (Liam Stewart)</para></listitem>
<listitem><para>Fix for SELECT 'id' AS xxx FROM table (Dave Cramer)</para></listitem>
<listitem><para>Fix DatabaseMetaData to show precision properly (Mark Lillywhite)</para></listitem>
<listitem><para>New getImported/getExported keys (Jason Davies)</para></listitem>
<listitem><para>MD5 password encryption support (Jeremy Wohl)</para></listitem>
<listitem><para>Fix to actually use type cache (Ned Wolpert)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>ODBC</title>
<itemizedlist>
<listitem><para>Remove query size limit (Hiroshi)</para></listitem>
<listitem><para>Remove text field size limit (Hiroshi)</para></listitem>
<listitem><para>Fix for SQLPrimaryKeys in multibyte mode (Hiroshi)</para></listitem>
<listitem><para>Allow ODBC procedure calls (Hiroshi)</para></listitem>
<listitem><para>Improve boolean handing (Aidan Mountford)</para></listitem>
<listitem><para>Most configuration options now settable via DSN (Hiroshi)</para></listitem>
<listitem><para>Multibyte, performance fixes (Hiroshi)</para></listitem>
<listitem><para>Allow driver to be used with iODBC or unixODBC (Peter E)</para></listitem>
<listitem><para>MD5 password encryption support (Bruce)</para></listitem>
<listitem><para>Add more compatibility functions to odbc.sql (Peter E)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title><application>ECPG</></title>
<itemizedlist>
<listitem><para>EXECUTE ... INTO implemented (Christof Petig)</para></listitem>
<listitem><para>Multiple row descriptor support (e.g. CARDINALITY) (Christof Petig)</para></listitem>
<listitem><para>Fix for GRANT parameters (Lee Kindness)</para></listitem>
<listitem><para>Fix INITIALLY DEFERRED bug</para></listitem>
<listitem><para>Various bug fixes (Michael, Christof Petig)</para></listitem>
<listitem><para>Auto allocation for indicator variable arrays (int *ind_p=NULL)</para></listitem>
<listitem><para>Auto allocation for string arrays (char **foo_pp=NULL)</para></listitem>
<listitem><para>ECPGfree_auto_mem fixed</para></listitem>
<listitem><para>All function names with external linkage are now prefixed by ECPG</para></listitem>
<listitem><para>Fixes for arrays of structures (Michael)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Misc. Interfaces</title>
<itemizedlist>
<listitem><para>Python fix fetchone() (Gerhard Haring)</para></listitem>
<listitem><para>Use UTF, Unicode in Tcl where appropriate (Vsevolod Lobko, Reinhard Max)</para></listitem>
<listitem><para>Add Tcl COPY TO/FROM (ljb)</para></listitem>
<listitem><para>Prevent output of default index op class in <application>pg_dump</> (Tom)</para></listitem>
<listitem><para>Fix libpgeasy memory leak (Bruce)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Build and Install</title>
<itemizedlist>
<listitem><para>Configure, dynamic loader, and shared library fixes (Peter E)</para></listitem>
<listitem><para>Fixes in QNX 4 port (Bernd Tegge)</para></listitem>
<listitem><para>Fixes in Cygwin and Windows ports (Jason Tishler, Gerhard Haring, Dmitry Yurtaev, Darko Prenosil, Mikhail Terekhov)</para></listitem>
<listitem><para>Fix for Windows socket communication failures (Magnus, Mikhail Terekhov)</para></listitem>
<listitem><para>Hurd compile fix (Oliver Elphick)</para></listitem>
<listitem><para>BeOS fixes (Cyril Velter)</para></listitem>
<listitem><para>Remove configure --enable-unicode-conversion, now enabled by multibyte (Tatsuo)</para></listitem>
<listitem><para>AIX fixes (Tatsuo, Andreas)</para></listitem>
<listitem><para>Fix parallel make (Peter E)</para></listitem>
<listitem><para>Install SQL language manual pages into OS-specific directories (Peter E)</para></listitem>
<listitem><para>Rename config.h to pg_config.h (Peter E)</para></listitem>
<listitem><para>Reorganize installation layout of header files (Peter E)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Source Code</title>
<itemizedlist>
<listitem><para>Remove SEP_CHAR (Bruce)</para></listitem>
<listitem><para>New GUC hooks (Tom)</para></listitem>
<listitem><para>Merge GUC and command line handling (Marko Kreen)</para></listitem>
<listitem><para>Remove EXTEND INDEX (Martijn van Oosterhout, Tom)</para></listitem>
<listitem><para>New pgjindent utility to indent java code (Bruce)</para></listitem>
<listitem><para>Remove define of true/false when compiling under C++ (Leandro Fanzone, Tom)</para></listitem>
<listitem><para>pgindent fixes (Bruce, Tom)</para></listitem>
<listitem><para>Replace strcasecmp() with strcmp() where appropriate (Peter E)</para></listitem>
<listitem><para>Dynahash portability improvements (Tom)</para></listitem>
<listitem><para>Add 'volatile' usage in spinlock structures</para></listitem>
<listitem><para>Improve signal handling logic (Tom)</para></listitem>
</itemizedlist>
  </sect3>

  <sect3>
   <title>Contrib</title>
<itemizedlist>
<listitem><para>New contrib/rtree_gist (Oleg Bartunov, Teodor Sigaev)</para></listitem>
<listitem><para>New contrib/tsearch full-text indexing (Oleg, Teodor Sigaev)</para></listitem>
<listitem><para>Add contrib/dblink for remote database access (Joe Conway)</para></listitem>
<listitem><para>contrib/ora2pg Oracle conversion utility (Gilles Darold)</para></listitem>
<listitem><para>contrib/xml XML conversion utility (John Gray)</para></listitem>
<listitem><para>contrib/fulltextindex fixes (Christopher Kings-Lynne)</para></listitem>
<listitem><para>New contrib/fuzzystrmatch with levenshtein and metaphone, soundex merged (Joe Conway)</para></listitem>
<listitem><para>Add contrib/intarray boolean queries, binary search, fixes (Oleg Bartunov)</para></listitem>
<listitem><para>New pg_upgrade utility (Bruce)</para></listitem>
<listitem><para>Add new pg_resetxlog options (Bruce, Tom)</para></listitem>
</itemizedlist>
  </sect3>
 </sect2>
</sect1>


 <sect1 id="release-7-1-3">
  <title>Release 7.1.3</title>

  <note>
  <title>Release date</title>
  <simpara>2001-08-15</simpara>
  </note>

  <sect2>
   <title>Migration to Version 7.1.3</title>

   <para>
    A dump/restore is <emphasis>not</emphasis> required for those running
    7.1.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Remove unused WAL segments of large transactions (Tom)
Multiaction rule fix (Tom)
PL/pgSQL memory allocation fix (Jan)
VACUUM buffer fix (Tom)
Regression test fixes (Tom)
pg_dump fixes for GRANT/REVOKE/comments on views, user-defined types (Tom)
Fix subselects with DISTINCT ON or LIMIT (Tom)
BeOS fix
Disable COPY TO/FROM a view (Tom)
Cygwin build (Jason Tishler)
    </programlisting>
   </para>
  </sect2>
 </sect1>


 <sect1 id="release-7-1-2">
  <title>Release 7.1.2</title>

  <note>
  <title>Release date</title>
  <simpara>2001-05-11</simpara>
  </note>

  <para>
   This has one fix from 7.1.1.
  </para>


  <sect2>
   <title>Migration to Version 7.1.2</title>

   <para>
    A dump/restore is <emphasis>not</emphasis> required for those running
    7.1.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Fix PL/pgSQL SELECTs when returning no rows
Fix for psql backslash core dump
Referential integrity privilege fix
Optimizer fixes
pg_dump cleanups
    </programlisting>
   </para>
  </sect2>
 </sect1>


 <sect1 id="release-7-1-1">
  <title>Release 7.1.1</title>

  <note>
  <title>Release date</title>
  <simpara>2001-05-05</simpara>
  </note>

  <para>
   This has a variety of fixes from 7.1.
  </para>


  <sect2>
   <title>Migration to Version 7.1.1</title>

   <para>
    A dump/restore is <emphasis>not</emphasis> required for those running
    7.1.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Fix for numeric MODULO operator (Tom)
pg_dump fixes (Philip)
pg_dump can dump 7.0 databases (Philip)
readline 4.2 fixes (Peter E)
JOIN fixes (Tom)
AIX, MSWIN, VAX, N32K fixes (Tom)
Multibytes fixes (Tom)
Unicode fixes (Tatsuo)
Optimizer improvements (Tom)
Fix for whole rows in functions (Tom)
Fix for pg_ctl and option strings with spaces (Peter E)
ODBC fixes (Hiroshi)
EXTRACT can now take string argument (Thomas)
Python fixes (Darcy)
    </programlisting>
   </para>
  </sect2>
 </sect1>


 <sect1 id="release-7-1">
  <title>Release 7.1</title>

  <note>
  <title>Release date</title>
  <simpara>2001-04-13</simpara>
  </note>

  <para>
       This release focuses on removing limitations that have existed in the
       <productname>PostgreSQL</productname> code for many years.
  </para>

  <para>
   Major changes in this release:
  </para>

  <variablelist>
   <varlistentry>
    <term>
      Write-ahead Log (WAL)
    </term>
    <listitem>
     <para>
To maintain database consistency in case of an operating system crash,
previous releases of <productname>PostgreSQL</productname> have forced
all data modifications to disk before each transaction commit.  With
WAL, only one log file must be flushed to disk, greatly improving
performance.  If you have been using -F in previous releases to
disable disk flushes, you might want to consider discontinuing its use.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
      TOAST
    </term>
    <listitem>
     <para>
      TOAST - Previous releases had a compiled-in row length limit,
typically 8k - 32k. This limit made storage of long text fields
difficult.  With TOAST, long rows of any length can be stored with good
performance.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
      Outer Joins
    </term>
    <listitem>
     <para>
We now support outer joins.  The UNION/NOT IN
workaround for outer joins is no longer required.  We use the SQL92
outer join syntax.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
      Function Manager
    </term>
    <listitem>
     <para>
The previous C function manager did not
handle null values properly, nor did it support 64-bit <acronym>CPU</acronym>'s (Alpha).  The new
function manager does.  You can continue using your old custom
functions, but you might want to rewrite them in the future to use the new
function manager call interface.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
      Complex Queries
    </term>
    <listitem>
     <para>
A large number of complex queries that were
unsupported in previous releases now work.  Many combinations of views,
aggregates, UNION, LIMIT, cursors, subqueries, and inherited tables
now work properly. Inherited tables are now accessed by default.
Subqueries in FROM are now supported.
     </para>
    </listitem>
   </varlistentry>

  </variablelist>

  <sect2>
   <title>Migration to Version 7.1</title>

   <para>
       A dump/restore using pg_dump is required for those wishing to migrate
       data from any previous release.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Bug Fixes
---------
Many multibyte/Unicode/locale fixes (Tatsuo and others)
More reliable ALTER TABLE RENAME (Tom)
Kerberos V fixes (David Wragg)
Fix for INSERT INTO...SELECT where targetlist has subqueries (Tom)
Prompt username/password on standard error (Bruce)
Large objects inv_read/inv_write fixes (Tom)
Fixes for to_char(), to_date(), to_ascii(), and to_timestamp() (Karel,
   Daniel Baldoni)
Prevent query expressions from leaking memory (Tom)
Allow UPDATE of arrays elements (Tom)
Wake up lock waiters during cancel (Hiroshi)
Fix rare cursor crash when using hash join (Tom)
Fix for DROP TABLE/INDEX in rolled-back transaction (Hiroshi)
Fix psql crash from \l+ if MULTIBYTE enabled (Peter E)
Fix truncation of rule names during CREATE VIEW (Ross Reedstrom)
Fix PL/perl (Alex Kapranoff)
Disallow LOCK on views (Mark Hollomon)
Disallow INSERT/UPDATE/DELETE on views (Mark Hollomon)
Disallow DROP RULE, CREATE INDEX, TRUNCATE on views (Mark Hollomon)
Allow PL/pgSQL accept non-ASCII identifiers (Tatsuo)
Allow views to proper handle GROUP BY, aggregates, DISTINCT (Tom)
Fix rare failure with TRUNCATE command (Tom)
Allow UNION/INTERSECT/EXCEPT to be used with ALL, subqueries, views,
   DISTINCT, ORDER BY, SELECT...INTO (Tom)
Fix parser failures during aborted transactions (Tom)
Allow temporary relations to properly clean up indexes (Bruce)
Fix VACUUM problem with moving rows in same page (Tom)
Modify pg_dump to better handle user-defined items in template1 (Philip)
Allow LIMIT in VIEW (Tom)
Require cursor FETCH to honor LIMIT (Tom)
Allow PRIMARY/FOREIGN Key definitions on inherited columns (Stephan)
Allow ORDER BY, LIMIT in subqueries (Tom)
Allow UNION in CREATE RULE (Tom)
Make ALTER/DROP TABLE rollback-able (Vadim, Tom)
Store initdb collation in pg_control so collation cannot be changed (Tom)
Fix INSERT...SELECT with rules (Tom)
Fix FOR UPDATE inside views and subselects (Tom)
Fix OVERLAPS operators conform to SQL92 spec regarding NULLs (Tom)
Fix lpad() and rpad() to handle length less than input string (Tom)
Fix use of NOTIFY in some rules (Tom)
Overhaul btree code (Tom)
Fix NOT NULL use in Pl/pgSQL variables (Tom)
Overhaul GIST code (Oleg)
Fix CLUSTER to preserve constraints and column default (Tom)
Improved deadlock detection handling (Tom)
Allow multiple SERIAL columns in a table (Tom)
Prevent occasional index corruption (Vadim)

Enhancements
------------
Add OUTER JOINs (Tom)
Function manager overhaul (Tom)
Allow ALTER TABLE RENAME on indexes (Tom)
Improve CLUSTER (Tom)
Improve ps status display for more platforms (Peter E, Marc)
Improve CREATE FUNCTION failure message (Ross)
JDBC improvements (Peter, Travis Bauer, Christopher Cain, William Webber,
   Gunnar)
Grand Unified Configuration scheme/GUC.  Many options can now be set in
   data/postgresql.conf, postmaster/postgres flags, or SET commands (Peter E)
Improved handling of file descriptor cache (Tom)
New warning code about auto-created table alias entries (Bruce)
Overhaul initdb process (Tom, Peter E)
Overhaul of inherited tables; inherited tables now accessed by default;
  new ONLY key word prevents it (Chris Bitmead, Tom)
ODBC cleanups/improvements (Nick Gorham, Stephan Szabo, Zoltan Kovacs,
   Michael Fork)
Allow renaming of temp tables (Tom)
Overhaul memory manager contexts (Tom)
pg_dumpall uses CREATE USER or CREATE GROUP rather using COPY (Peter E)
Overhaul pg_dump (Philip Warner)
Allow pg_hba.conf secondary password file to specify only username (Peter E)
Allow TEMPORARY or TEMP key word when creating temporary tables (Bruce)
New memory leak checker (Karel)
New SET SESSION CHARACTERISTICS (Thomas)
Allow nested block comments (Thomas)
Add WITHOUT TIME ZONE type qualifier (Thomas)
New ALTER TABLE ADD CONSTRAINT (Stephan)
Use NUMERIC accumulators for INTEGER aggregates (Tom)
Overhaul aggregate code (Tom)
New VARIANCE and STDDEV() aggregates
Improve dependency ordering of pg_dump (Philip)
New pg_restore command (Philip)
New pg_dump tar output option (Philip)
New pg_dump of large objects  (Philip)
New ESCAPE option to LIKE (Thomas)
New case-insensitive LIKE - ILIKE (Thomas)
Allow functional indexes to use binary-compatible type (Tom)
Allow SQL functions to be used in more contexts (Tom)
New pg_config utility (Peter E)
New PL/pgSQL EXECUTE command which allows dynamic SQL and utility statements
   (Jan)
New PL/pgSQL GET DIAGNOSTICS statement for SPI value access (Jan)
New quote_identifiers() and quote_literal() functions (Jan)
New ALTER TABLE table OWNER TO user command (Mark Hollomon)
Allow subselects in FROM, i.e. FROM (SELECT ...) [AS] alias (Tom)
Update PyGreSQL to version 3.1 (D'Arcy)
Store tables as files named by OID (Vadim)
New SQL function setval(seq,val,bool) for use in pg_dump (Philip)
Require DROP VIEW to remove views, no DROP TABLE (Mark)
Allow DROP VIEW view1, view2 (Mark)
Allow multiple objects in DROP INDEX, DROP RULE, and DROP TYPE (Tom)
Allow automatic conversion to/from Unicode (Tatsuo, Eiji)
New /contrib/pgcrypto hashing functions (Marko Kreen)
New pg_dumpall --globals-only option (Peter E)
New CHECKPOINT command for WAL which creates new WAL log file (Vadim)
New AT TIME ZONE syntax (Thomas)
Allow location of Unix domain socket to be configurable (David J. MacKenzie)
Allow postmaster to listen on a specific IP address (David J. MacKenzie)
Allow socket path name to be specified in hostname by using leading slash
   (David J. MacKenzie)
Allow CREATE DATABASE to specify template database (Tom)
New utility to convert MySQL schema dumps to SQL92 and PostgreSQL (Thomas)
New /contrib/rserv replication toolkit (Vadim)
New file format for COPY BINARY (Tom)
New /contrib/oid2name to map numeric files to table names (B Palmer)
New "idle in transaction" ps status message (Marc)
Update to pgaccess 0.98.7 (Constantin Teodorescu)
pg_ctl now defaults to -w (wait) on shutdown, new -l (log) option
Add rudimentary dependency checking to pg_dump (Philip)

Types
-----
Fix INET/CIDR type ordering and add new functions (Tom)
Make OID behave as an unsigned type (Tom)
Allow BIGINT as synonym for INT8 (Peter E)
New int2 and int8 comparison operators (Tom)
New BIT and BIT VARYING types (Adriaan Joubert, Tom, Peter E)
CHAR() no longer faster than VARCHAR() because of TOAST (Tom)
New GIST seg/cube examples (Gene Selkov)
Improved round(numeric) handling (Tom)
Fix CIDR output formatting (Tom)
New CIDR abbrev() function (Tom)

Performance
-----------
Write-Ahead Log (WAL) to provide crash recovery with less performance
   overhead (Vadim)
ANALYZE stage of VACUUM no longer exclusively locks table (Bruce)
Reduced file seeks (Denis Perchine)
Improve BTREE code for duplicate keys (Tom)
Store all large objects in a single table (Denis Perchine, Tom)
Improve memory allocation performance (Karel, Tom)

Source Code
-----------
New function manager call conventions (Tom)
SGI portability fixes (David Kaelbling)
New configure --enable-syslog option (Peter E)
New BSDI README (Bruce)
configure script moved to top level, not /src (Peter E)
Makefile/configuration/compilation overhaul (Peter E)
New configure --with-python option (Peter E)
Solaris cleanups (Peter E)
Overhaul /contrib Makefiles (Karel)
New OpenSSL configuration option (Magnus, Peter E)
AIX fixes (Andreas)
QNX fixes (Maurizio)
New heap_open(), heap_openr() API (Tom)
Remove colon and semi-colon operators (Thomas)
New pg_class.relkind value for views (Mark Hollomon)
Rename ichar() to chr() (Karel)
New documentation for btrim(), ascii(), chr(), repeat() (Karel)
Fixes for NT/Cygwin (Pete Forman)
AIX port fixes (Andreas)
New BeOS port (David Reid, Cyril Velter)
Add proofreader's changes to docs (Addison-Wesley, Bruce)
New Alpha spinlock code (Adriaan Joubert, Compaq)
UnixWare port overhaul (Peter E)
New Darwin/MacOS X port (Peter Bierman, Bruce Hartzler)
New FreeBSD Alpha port (Alfred)
Overhaul shared memory segments (Tom)
Add IBM S/390 support (Neale Ferguson)
Moved macmanuf to /contrib (Larry Rosenman)
Syslog improvements (Larry Rosenman)
New template0 database that contains no user additions (Tom)
New /contrib/cube and /contrib/seg GIST sample code (Gene Selkov)
Allow NetBSD's libedit instead of readline (Peter)
Improved assembly language source code format (Bruce)
New contrib/pg_logger
New --template option to createdb
New contrib/pg_control utility (Oliver)
New FreeBSD tools ipc_check, start-scripts/freebsd
    </programlisting>
   </para>
  </sect2>
 </sect1>


 <sect1 id="release-7-0-3">
  <title>Release 7.0.3</title>

  <note>
  <title>Release date</title>
  <simpara>2000-11-11</simpara>
  </note>

  <para>
   This has a variety of fixes from 7.0.2.
  </para>


  <sect2>
   <title>Migration to Version 7.0.3</title>

   <para>
    A dump/restore is <emphasis>not</emphasis> required for those running
    7.0.*.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Jdbc fixes (Peter)
Large object fix (Tom)
Fix lean in COPY WITH OIDS leak (Tom)
Fix backwards-index-scan (Tom)
Fix SELECT ... FOR UPDATE so it checks for duplicate keys (Hiroshi)
Add --enable-syslog to configure (Marc)
Fix abort transaction at backend exit in rare cases (Tom)
Fix for psql \l+ when multibyte enabled (Tatsuo)
Allow PL/pgSQL to accept non ascii identifiers (Tatsuo)
Make vacuum always flush buffers (Tom)
Fix to allow cancel while waiting for a lock (Hiroshi)
Fix for memory allocation problem in user authentication code (Tom)
Remove bogus use of int4out() (Tom)
Fixes for multiple subqueries in COALESCE or BETWEEN (Tom)
Fix for failure of triggers on heap open in certain cases (Jeroen van
   Vianen)
Fix for erroneous selectivity of not-equals (Tom)
Fix for erroneous use of strcmp() (Tom)
Fix for bug where storage manager accesses items beyond end of file
   (Tom)
Fix to include kernel errno message in all smgr elog messages (Tom)
Fix for '.' not in PATH at build time (SL Baur)
Fix for out-of-file-descriptors error (Tom)
Fix to make pg_dump dump 'iscachable' flag for functions (Tom)
Fix for subselect in targetlist of Append node (Tom)
Fix for mergejoin plans (Tom)
Fix TRUNCATE failure on relations with indexes (Tom)
Avoid database-wide restart on write error (Hiroshi)
Fix nodeMaterial to honor chgParam by recomputing its output (Tom)
Fix VACUUM problem with moving chain of update row versions when source
   and destination of a row version lie on the same page (Tom)
Fix user.c CommandCounterIncrement (Tom)
Fix for AM/PM boundary problem in to_char() (Karel Zak)
Fix TIME aggregate handling (Tom)
Fix to_char() to avoid coredump on NULL input (Tom)
Buffer fix (Tom)
Fix for inserting/copying longer multibyte strings into char() data
   types (Tatsuo)
Fix for crash of backend, on abort (Tom)
    </programlisting>
   </para>
  </sect2>
 </sect1>


 <sect1 id="release-7-0-2">
  <title>Release 7.0.2</title>

  <note>
  <title>Release date</title>
  <simpara>2000-06-05</simpara>
  </note>

  <para>
   This is a repackaging of 7.0.1 with added documentation.
  </para>


  <sect2>
   <title>Migration to Version 7.0.2</title>

   <para>
    A dump/restore is <emphasis>not</emphasis> required for those running
    7.*.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Added documentation to tarball.
    </programlisting>
   </para>
  </sect2>
 </sect1>


 <sect1 id="release-7-0-1">
  <title>Release 7.0.1</title>

  <note>
  <title>Release date</title>
  <simpara>2000-06-01</simpara>
  </note>

  <para>
   This is a cleanup release for 7.0.
  </para>

  <sect2>
   <title>Migration to Version 7.0.1</title>

   <para>
    A dump/restore is <emphasis>not</emphasis> required for those running
    7.0.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Fix many CLUSTER failures (Tom)
Allow ALTER TABLE RENAME works on indexes (Tom)
Fix plpgsql to handle datetime-&gt;timestamp and timespan-&gt;interval (Bruce)
New configure --with-setproctitle switch to use setproctitle() (Marc, Bruce)
Fix the off by one errors in ResultSet from 6.5.3, and more.
jdbc ResultSet fixes (Joseph Shraibman)
optimizer tunings (Tom)
Fix create user for pgaccess
Fix for UNLISTEN failure
IRIX fixes (David Kaelbling)
QNX fixes (Andreas Kardos)
Reduce COPY IN lock level (Tom)
Change libpqeasy to use PQconnectdb() style parameters (Bruce)
Fix pg_dump to handle OID indexes (Tom)
Fix small memory leak (Tom)
Solaris fix for createdb/dropdb (Tatsuo)
Fix for non-blocking connections (Alfred Perlstein)
Fix improper recovery after RENAME TABLE failures (Tom)
Copy pg_ident.conf.sample into /lib directory in install (Bruce)
Add SJIS UDC (NEC selection IBM kanji) support (Eiji Tokuya)
Fix too long syslog message (Tatsuo)
Fix problem with quoted indexes that are too long (Tom)
JDBC ResultSet.getTimestamp() fix (Gregory Krasnow &amp; Floyd Marinescu)
ecpg changes (Michael)
    </programlisting>
   </para>
  </sect2>
 </sect1>

 <sect1 id="release-7-0">
  <title>Release 7.0</title>

  <note>
  <title>Release date</title>
  <simpara>2000-05-08</simpara>
  </note>

  <para>
   This release contains improvements in many areas, demonstrating
   the continued growth of <productname>PostgreSQL</productname>.
   There are more improvements and fixes in 7.0 than in any previous
   release. The developers have confidence that this is the best
   release yet; we do our best to put out only solid releases, and
   this one is no exception.
  </para>

  <para>
   Major changes in this release:
  </para>

  <variablelist>
   <varlistentry>
    <term>
     Foreign Keys
    </term>
    <listitem>
     <para>
      Foreign keys are now implemented, with the exception of PARTIAL MATCH
      foreign keys. Many users have been asking for this feature, and we are
      pleased to offer it.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     Optimizer Overhaul
    </term>
    <listitem>
     <para>
      Continuing on work started a year ago, the optimizer has been
      improved, allowing better query plan selection and faster performance
      with less memory usage.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     Updated <application>psql</application>
    </term>
    <listitem>
     <para>
      <application>psql</application>, our interactive terminal monitor, has been
      updated with a variety of new features. See the <application>psql</application> manual page for details.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term>
     Join Syntax
    </term>
    <listitem>
     <para>
      SQL92 join syntax is now supported, though only as
      <literal>INNER JOIN</> for this release. <literal>JOIN</>,
      <literal>NATURAL JOIN</>, <literal>JOIN</>/<literal>USING</>,
      and <literal>JOIN</>/<literal>ON</> are available, as are
      column correlation names.
     </para>
    </listitem>

   </varlistentry>
  </variablelist>

  <sect2>
   <title>Migration to Version 7.0</title>

   <para>
    A dump/restore using <application>pg_dump</application>
    is required for those wishing to migrate data from any
    previous release of <productname>PostgreSQL</productname>.
    For those upgrading from 6.5.*, you can instead use
    <application>pg_upgrade</application> to upgrade to this
    release; however, a full dump/reload installation is always the
    most robust method for upgrades.
   </para>

   <para>
    Interface and compatibility issues to consider for the new
    release include:
   </para>

   <itemizedlist>
    <listitem>
     <para>
      The date/time types <type>datetime</type> and
      <type>timespan</type> have been superseded by the
      SQL92-defined types <type>timestamp</type> and
      <type>interval</type>. Although there has been some effort to
      ease the transition by allowing
      <productname>PostgreSQL</productname> to recognize
      the deprecated type names and translate them to the new type
      names, this mechanism cannot be completely transparent to
      your existing application.
     </para>
    </listitem>

    <listitem>
     <para>
      The optimizer has been substantially improved in the area of
      query cost estimation. In some cases, this will result in
      decreased query times as the optimizer makes a better choice
      for the preferred plan. However, in a small number of cases,
      usually involving pathological distributions of data, your
      query times might go up. If you are dealing with large amounts
      of data, you might want to check your queries to verify
      performance.
     </para>
    </listitem>

    <listitem>
     <para>
      The <acronym>JDBC</acronym> and <acronym>ODBC</acronym>
      interfaces have been upgraded and extended.
     </para>
    </listitem>

    <listitem>
     <para>
      The string function <function>CHAR_LENGTH</function> is now a
      native function. Previous versions translated this into a call
      to <function>LENGTH</function>, which could result in
      ambiguity with other types implementing
      <function>LENGTH</function> such as the geometric types.
     </para>
    </listitem>
   </itemizedlist>
  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Bug Fixes
---------
Prevent function calls exceeding maximum number of arguments (Tom)
Improve CASE construct (Tom)
Fix SELECT coalesce(f1,0) FROM int4_tbl GROUP BY f1 (Tom)
Fix SELECT sentence.words[0] FROM sentence GROUP BY sentence.words[0] (Tom)
Fix GROUP BY scan bug (Tom)
Improvements in SQL grammar processing (Tom)
Fix for views involved in INSERT ... SELECT ... (Tom)
Fix for SELECT a/2, a/2 FROM test_missing_target GROUP BY a/2 (Tom)
Fix for subselects in INSERT ... SELECT (Tom)
Prevent INSERT ... SELECT ... ORDER BY (Tom)
Fixes for relations greater than 2GB, including vacuum
Improve propagating system table changes to other backends (Tom)
Improve propagating user table changes to other backends (Tom)
Fix handling of temp tables in complex situations (Bruce, Tom)
Allow table locking at table open, improving concurrent reliability (Tom)
Properly quote sequence names in pg_dump (Ross J. Reedstrom)
Prevent DROP DATABASE while others accessing
Prevent any rows from being returned by GROUP BY if no rows processed (Tom)
Fix SELECT COUNT(1) FROM table WHERE ...' if no rows matching WHERE (Tom)
Fix pg_upgrade so it works for MVCC (Tom)
Fix for SELECT ... WHERE x IN (SELECT ... HAVING SUM(x) &gt; 1) (Tom)
Fix for "f1 datetime DEFAULT 'now'"  (Tom)
Fix problems with CURRENT_DATE used in DEFAULT (Tom)
Allow comment-only lines, and ;;; lines too. (Tom)
Improve recovery after failed disk writes, disk full (Hiroshi)
Fix cases where table is mentioned in FROM but not joined (Tom)
Allow HAVING clause without aggregate functions (Tom)
Fix for "--" comment and no trailing newline, as seen in perl interface
Improve pg_dump failure error reports (Bruce)
Allow sorts and hashes to exceed 2GB file sizes (Tom)
Fix for pg_dump dumping of inherited rules (Tom)
Fix for NULL handling comparisons (Tom)
Fix inconsistent state caused by failed CREATE/DROP commands (Hiroshi)
Fix for dbname with dash
Prevent DROP INDEX from interfering with other backends (Tom)
Fix file descriptor leak in verify_password()
Fix for "Unable to identify an operator =$" problem
Fix ODBC so no segfault if CommLog and Debug enabled (Dirk Niggemann)
Fix for recursive exit call (Massimo)
Fix for extra-long timezones (Jeroen van Vianen)
Make pg_dump preserve primary key information (Peter E)
Prevent databases with single quotes (Peter E)
Prevent DROP DATABASE inside  transaction (Peter E)
ecpg memory leak fixes (Stephen Birch)
Fix for SELECT null::text, SELECT int4fac(null) and SELECT 2 + (null) (Tom)
Y2K timestamp fix (Massimo)
Fix for VACUUM 'HEAP_MOVED_IN was not expected' errors (Tom)
Fix for views with tables/columns containing spaces  (Tom)
Prevent privileges on indexes (Peter E)
Fix for spinlock stuck problem when error is generated (Hiroshi)
Fix ipcclean on Linux
Fix handling of NULL constraint conditions (Tom)
Fix memory leak in odbc driver (Nick Gorham)
Fix for privilege check on UNION tables (Tom)
Fix to allow SELECT 'a' LIKE 'a' (Tom)
Fix for SELECT 1 + NULL (Tom)
Fixes to CHAR
Fix log() on numeric type (Tom)
Deprecate ':' and ';' operators
Allow vacuum of temporary tables
Disallow inherited columns with the same name as new columns
Recover or force failure when disk space is exhausted (Hiroshi)
Fix INSERT INTO ... SELECT with AS columns matching result columns
Fix INSERT ... SELECT ... GROUP BY groups by target columns not source columns (Tom)
Fix CREATE TABLE test (a char(5) DEFAULT text '', b int4) with INSERT (Tom)
Fix UNION with LIMIT
Fix CREATE TABLE x AS SELECT 1 UNION SELECT 2
Fix CREATE TABLE test(col char(2) DEFAULT user)
Fix mismatched types in CREATE TABLE ... DEFAULT
Fix SELECT * FROM pg_class where oid in (0,-1)
Fix SELECT COUNT('asdf') FROM pg_class WHERE oid=12
Prevent user who can create databases can modifying pg_database table (Peter E)
Fix btree to give a useful elog when key &gt; 1/2 (page - overhead) (Tom)
Fix INSERT of 0.0 into DECIMAL(4,4) field (Tom)

Enhancements
------------
New CLI interface include file sqlcli.h, based on SQL3/SQL98
Remove all limits on query length, row length limit still exists (Tom)
Update jdbc protocol to 2.0 (Jens Glaser <email>jens@jens.de</email>)
Add TRUNCATE command to quickly truncate relation (Mike Mascari)
Fix to give super user and createdb user proper update catalog rights (Peter E)
Allow ecpg bool variables to have NULL values (Christof)
Issue ecpg error if NULL value for variable with no NULL indicator (Christof)
Allow ^C to cancel COPY command (Massimo)
Add SET FSYNC and SHOW PG_OPTIONS commands(Massimo)
Function name overloading for dynamically-loaded C functions (Frankpitt)
Add CmdTuples() to libpq++(Vince)
New CREATE CONSTRAINT TRIGGER and SET CONSTRAINTS commands(Jan)
Allow CREATE FUNCTION/WITH clause to be used for all language types
configure --enable-debug adds -g (Peter E)
configure --disable-debug removes -g (Peter E)
Allow more complex default expressions (Tom)
First real FOREIGN KEY constraint trigger functionality (Jan)
Add FOREIGN KEY ... MATCH FULL ... ON DELETE CASCADE (Jan)
Add FOREIGN KEY ... MATCH &lt;unspecified&gt; referential actions (Don Baccus)
Allow WHERE restriction on ctid (physical heap location) (Hiroshi)
Move pginterface from contrib to interface directory, rename to pgeasy (Bruce)
Change pgeasy connectdb() parameter ordering (Bruce)
Require SELECT DISTINCT target list to have all ORDER BY columns (Tom)
Add Oracle's COMMENT ON command (Mike Mascari <email>mascarim@yahoo.com</email>)
libpq's PQsetNoticeProcessor function now returns previous hook(Peter E)
Prevent PQsetNoticeProcessor from being set to NULL (Peter E)
Make USING in COPY optional (Bruce)
Allow subselects in the target list (Tom)
Allow subselects on the left side of comparison operators (Tom)
New parallel regression test (Jan)
Change backend-side COPY to write files with permissions 644 not 666 (Tom)
Force permissions on PGDATA directory to be secure, even if it exists (Tom)
Added psql LASTOID variable to return last inserted oid (Peter E)
Allow concurrent vacuum and remove pg_vlock vacuum lock file (Tom)
Add privilege check for vacuum (Peter E)
New libpq functions to allow asynchronous connections: PQconnectStart(),
  PQconnectPoll(), PQresetStart(), PQresetPoll(), PQsetenvStart(),
  PQsetenvPoll(), PQsetenvAbort (Ewan Mellor)
New libpq PQsetenv() function (Ewan Mellor)
create/alter user extension (Peter E)
New postmaster.pid and postmaster.opts under $PGDATA (Tatsuo)
New scripts for create/drop user/db (Peter E)
Major psql overhaul (Peter E)
Add const to libpq interface (Peter E)
New libpq function PQoidValue (Peter E)
Show specific non-aggregate causing problem with GROUP BY (Tom)
Make changes to pg_shadow recreate pg_pwd file (Peter E)
Add aggregate(DISTINCT ...) (Tom)
Allow flag to control COPY input/output of NULLs (Peter E)
Make postgres user have a password by default (Peter E)
Add CREATE/ALTER/DROP GROUP (Peter E)
All administration scripts now support --long options (Peter E, Karel)
Vacuumdb script now supports --all option (Peter E)
ecpg new portable FETCH syntax
Add ecpg EXEC SQL IFDEF, EXEC SQL IFNDEF, EXEC SQL ELSE, EXEC SQL ELIF
       and EXEC SQL ENDIF directives
Add pg_ctl script to control backend start-up (Tatsuo)
Add postmaster.opts.default file to store start-up flags (Tatsuo)
Allow --with-mb=SQL_ASCII
Increase maximum number of index keys to 16 (Bruce)
Increase maximum number of function arguments to 16 (Bruce)
Allow configuration of maximum number of index keys and arguments (Bruce)
Allow unprivileged users to change their passwords (Peter E)
Password authentication enabled; required for new users (Peter E)
Disallow dropping a user who owns a database (Peter E)
Change initdb option --with-mb to --enable-multibyte
Add option for initdb to prompts for superuser password (Peter E)
Allow complex type casts like col::numeric(9,2) and col::int2::float8 (Tom)
Updated user interfaces on initdb, initlocation, pg_dump, ipcclean (Peter E)
New pg_char_to_encoding() and pg_encoding_to_char() functions (Tatsuo)
libpq non-blocking mode (Alfred Perlstein)
Improve conversion of types in casts that don't specify a length
New plperl internal programming language (Mark Hollomon)
Allow COPY IN to read file that do not end with a newline (Tom)
Indicate when long identifiers are truncated (Tom)
Allow aggregates to use type equivalency (Peter E)
Add Oracle's to_char(), to_date(), to_datetime(), to_timestamp(), to_number()
       conversion functions (Karel Zak &lt;zakkr@zf.jcu.cz&gt;)
Add SELECT DISTINCT ON (expr [, expr ...]) targetlist ... (Tom)
Check to be sure ORDER BY is compatible with the DISTINCT operation (Tom)
Add NUMERIC and int8 types to ODBC
Improve EXPLAIN results for Append, Group, Agg, Unique (Tom)
Add ALTER TABLE ... ADD FOREIGN KEY (Stephan Szabo)
Allow SELECT .. FOR UPDATE in PL/pgSQL (Hiroshi)
Enable backward sequential scan even after reaching EOF (Hiroshi)
Add btree indexing of boolean values, &gt;= and &lt;= (Don Baccus)
Print current line number when COPY FROM fails (Massimo)
Recognize POSIX time zone e.g. "PST+8" and "GMT-8" (Thomas)
Add DEC as synonym for DECIMAL (Thomas)
Add SESSION_USER as SQL92 key word, same as CURRENT_USER (Thomas)
Implement SQL92 column aliases (aka correlation names) (Thomas)
Implement SQL92 join syntax (Thomas)
Make INTERVAL reserved word allowed as a column identifier (Thomas)
Implement REINDEX command (Hiroshi)
Accept ALL in aggregate function SUM(ALL col) (Tom)
Prevent GROUP BY from using column aliases (Tom)
New psql \encoding option (Tatsuo)
Allow PQrequestCancel() to terminate when in waiting-for-lock state (Hiroshi)
Allow negation of a negative number in all cases
Add ecpg descriptors (Christof, Michael)
Allow CREATE VIEW v AS SELECT f1::char(8) FROM tbl
Allow casts with length, like foo::char(8)
New libpq functions PQsetClientEncoding(), PQclientEncoding() (Tatsuo)
Add support for SJIS user defined characters (Tatsuo)
Larger views/rules supported
Make libpq's PQconndefaults() thread-safe (Tom)
Disable // as comment to be ANSI conforming, should use -- (Tom)
Allow column aliases on views CREATE VIEW name (collist)
Fixes for views with subqueries (Tom)
Allow UPDATE table SET fld = (SELECT ...) (Tom)
SET command options no longer require quotes
Update pgaccess to 0.98.6
New SET SEED command
New pg_options.sample file
New SET FSYNC command (Massimo)
Allow pg_descriptions when creating tables
Allow pg_descriptions when creating types, columns, and functions
Allow psql \copy to allow delimiters (Peter E)
Allow psql to print nulls as distinct from "" [null] (Peter E)

Types
-----
Many array fixes (Tom)
Allow bare column names to be subscripted as arrays (Tom)
Improve type casting of int and float constants (Tom)
Cleanups for int8 inputs, range checking, and type conversion (Tom)
Fix for SELECT timespan('21:11:26'::time) (Tom)
netmask('x.x.x.x/0') is 255.255.255.255 instead of 0.0.0.0 (Oleg Sharoiko)
Add btree index on NUMERIC (Jan)
Perl fix for large objects containing NUL characters (Douglas Thomson)
ODBC fix for large objects (free)
Fix indexing of cidr data type
Fix for Ethernet MAC addresses (macaddr type) comparisons
Fix for date/time types when overflows happened in computations (Tom)
Allow array on int8 (Peter E)
Fix for rounding/overflow of NUMERIC type, like NUMERIC(4,4) (Tom)
Allow NUMERIC arrays
Fix bugs in NUMERIC ceil() and floor() functions (Tom)
Make char_length()/octet_length including trailing blanks (Tom)
Made abstime/reltime use int4 instead of time_t (Peter E)
New lztext data type for compressed text fields
Revise code to handle coercion of int and float constants (Tom)
Start at new code to implement a BIT and BIT VARYING type (Adriaan Joubert)
NUMERIC now accepts scientific notation (Tom)
NUMERIC to int4 rounds (Tom)
Convert float4/8 to NUMERIC properly (Tom)
Allow type conversion with NUMERIC (Thomas)
Make ISO date style (2000-02-16 09:33) the default (Thomas)
Add NATIONAL CHAR [ VARYING ] (Thomas)
Allow NUMERIC round and trunc to accept negative scales (Tom)
New TIME WITH TIME ZONE type (Thomas)
Add MAX()/MIN() on time type (Thomas)
Add abs(), mod(), fac() for int8 (Thomas)
Rename functions to round(), sqrt(), cbrt(), pow() for float8 (Thomas)
Add transcendental math functions (e.g. sin(), acos()) for float8 (Thomas)
Add exp() and ln() for NUMERIC type
Rename NUMERIC power() to pow() (Thomas)
Improved TRANSLATE() function (Edwin Ramirez, Tom)
Allow X=-Y operators  (Tom)
Allow SELECT float8(COUNT(*))/(SELECT COUNT(*) FROM t) FROM t GROUP BY f1; (Tom)
Allow LOCALE to use indexes in regular expression searches (Tom)
Allow creation of functional indexes to use default types

Performance
-----------
Prevent exponential space consumption with many AND's and OR's (Tom)
Collect attribute selectivity values for system columns (Tom)
Reduce memory usage of aggregates (Tom)
Fix for LIKE optimization to use indexes with multibyte encodings (Tom)
Fix r-tree index optimizer selectivity (Thomas)
Improve optimizer selectivity computations and functions (Tom)
Optimize btree searching for cases where many equal keys exist (Tom)
Enable fast LIKE index processing only if index present (Tom)
Re-use free space on index pages with duplicates (Tom)
Improve hash join processing (Tom)
Prevent descending sort if result is already sorted(Hiroshi)
Allow commuting of index scan query qualifications (Tom)
Prefer index scans in cases where ORDER BY/GROUP BY is required (Tom)
Allocate large memory requests in fix-sized chunks for performance (Tom)
Fix vacuum's performance by reducing memory allocation requests (Tom)
Implement constant-expression simplification (Bernard Frankpitt, Tom)
Use secondary columns to be used to determine start of index scan (Hiroshi)
Prevent quadruple use of disk space when doing internal sorting (Tom)
Faster sorting by calling fewer functions (Tom)
Create system indexes to match all system caches (Bruce, Hiroshi)
Make system caches use system indexes (Bruce)
Make all system indexes unique (Bruce)
Improve pg_statistics management for VACUUM speed improvement (Tom)
Flush backend cache less frequently (Tom, Hiroshi)
COPY now reuses previous memory allocation, improving performance (Tom)
Improve optimization cost estimation (Tom)
Improve optimizer estimate of range queries x &gt; lowbound AND x &lt; highbound (Tom)
Use DNF instead of CNF where appropriate (Tom, Taral)
Further cleanup for OR-of-AND WHERE-clauses (Tom)
Make use of index in OR clauses (x = 1 AND y = 2) OR (x = 2 AND y = 4) (Tom)
Smarter optimizer computations for random index page access (Tom)
New SET variable to control optimizer costs (Tom)
Optimizer queries based on LIMIT, OFFSET, and EXISTS qualifications (Tom)
Reduce optimizer internal housekeeping of join paths for speedup (Tom)
Major subquery speedup (Tom)
Fewer fsync writes when fsync is not disabled (Tom)
Improved LIKE optimizer estimates (Tom)
Prevent fsync in SELECT-only queries (Vadim)
Make index creation use psort code, because it is now faster (Tom)
Allow creation of sort temp tables &gt; 1 Gig

Source Tree Changes
-------------------
Fix for linux PPC compile
New generic expression-tree-walker subroutine (Tom)
Change form() to varargform() to prevent portability problems
Improved range checking for large integers on Alphas
Clean up #include in /include directory (Bruce)
Add scripts for checking includes (Bruce)
Remove un-needed #include's from *.c files (Bruce)
Change #include's to use &lt;&gt; and "" as appropriate (Bruce)
Enable Windows compilation of libpq
Alpha spinlock fix from Uncle George <email>gatgul@voicenet.com</email>
Overhaul of optimizer data structures (Tom)
Fix to cygipc library (Yutaka Tanida)
Allow pgsql to work on newer Cygwin snapshots (Dan)
New catalog version number (Tom)
Add Linux ARM
Rename heap_replace to heap_update
Update for QNX (Dr. Andreas Kardos)
New platform-specific regression handling (Tom)
Rename oid8 -&gt; oidvector and int28 -&gt; int2vector (Bruce)
Included all yacc and lex files into the distribution (Peter E.)
Remove lextest, no longer needed (Peter E)
Fix for libpq and psql on Windows (Magnus)
Internally change datetime and timespan into timestamp and interval (Thomas)
Fix for plpgsql on BSD/OS
Add SQL_ASCII test case to the regression test (Tatsuo)
configure --with-mb now deprecated (Tatsuo)
NT fixes
NetBSD fixes (Johnny C. Lam <email>lamj@stat.cmu.edu</email>)
Fixes for Alpha compiles
New multibyte encodings
    </programlisting>
   </para>
  </sect2>
 </sect1>

 <sect1 id="release-6-5-3">
  <title>Release 6.5.3</title>

  <note>
  <title>Release date</title>
  <simpara>1999-10-13</simpara>
  </note>

  <para>
   This is basically a cleanup release for 6.5.2.  We have added a new
   <application>PgAccess</> that was missing in 6.5.2, and installed an NT-specific fix.
  </para>


  <sect2>
   <title>Migration to Version 6.5.3</title>

   <para>
    A dump/restore is <emphasis>not</emphasis> required for those running
    6.5.*.
   </para>
  </sect2>
  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Updated version of pgaccess 0.98
NT-specific patch
Fix dumping rules on inherited tables
    </programlisting>
   </para>
  </sect2>
 </sect1>


 <sect1 id="release-6-5-2">
  <title>Release 6.5.2</title>

  <note>
  <title>Release date</title>
  <simpara>1999-09-15</simpara>
  </note>

  <para>
   This is basically a cleanup release for 6.5.1.  We have fixed a variety of
   problems reported by 6.5.1 users.
  </para>


  <sect2>
   <title>Migration to Version 6.5.2</title>

   <para>
    A dump/restore is <emphasis>not</emphasis> required for those running
    6.5.*.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
subselect+CASE fixes(Tom)
Add SHLIB_LINK setting for solaris_i386 and solaris_sparc ports(Daren Sefcik)
Fixes for CASE in WHERE join clauses(Tom)
Fix BTScan abort(Tom)
Repair the check for redundant UNIQUE and PRIMARY KEY indexes(Thomas)
Improve it so that it checks for multicolumn constraints(Thomas)
Fix for Windows making problem with MB enabled(Hiroki Kataoka)
Allow BSD yacc and bison to compile pl code(Bruce)
Fix SET NAMES working
int8 fixes(Thomas)
Fix vacuum's memory consumption(Hiroshi,Tatsuo)
Reduce the total memory consumption of vacuum(Tom)
Fix for timestamp(datetime)
Rule deparsing bugfixes(Tom)
Fix quoting problems in mkMakefile.tcldefs.sh.in and mkMakefile.tkdefs.sh.in(Tom)
This is to re-use space on index pages freed by vacuum(Vadim)
document -x for pg_dump(Bruce)
Fix for unary operators in rule deparser(Tom)
Comment out FileUnlink of excess segments during mdtruncate()(Tom)
IRIX linking fix from Yu Cao &gt;yucao@falcon.kla-tencor.com&lt;
Repair logic error in LIKE: should not return LIKE_ABORT
  when reach end of pattern before end of text(Tom)
Repair incorrect cleanup of heap memory allocation during transaction abort(Tom)
Updated version of pgaccess 0.98
    </programlisting>
   </para>
  </sect2>
 </sect1>

 <sect1 id="release-6-5-1">
  <title>Release 6.5.1</title>

  <note>
  <title>Release date</title>
  <simpara>1999-07-15</simpara>
  </note>

  <para>
   This is basically a cleanup release for 6.5.  We have fixed a variety of
   problems reported by 6.5 users.
  </para>

  <sect2>
   <title>Migration to Version 6.5.1</title>

   <para>
    A dump/restore is <emphasis>not</emphasis> required for those running
    6.5.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Add NT README file
Portability fixes for linux_ppc, IRIX, linux_alpha, OpenBSD, alpha
Remove QUERY_LIMIT, use SELECT...LIMIT
Fix for EXPLAIN on inheritance(Tom)
Patch to allow vacuum on multisegment tables(Hiroshi)
R-Tree optimizer selectivity fix(Tom)
ACL file descriptor leak fix(Atsushi Ogawa)
New expression subtree code(Tom)
Avoid disk writes for read-only transactions(Vadim)
Fix for removal of temp tables if last transaction was aborted(Bruce)
Fix to prevent too large row from being created(Bruce)
plpgsql fixes
Allow port numbers 32k - 64k(Bruce)
Add ^ precedence(Bruce)
Rename sort files called pg_temp to pg_sorttemp(Bruce)
Fix for microseconds in time values(Tom)
Tutorial source cleanup
New linux_m68k port
Fix for sorting of NULL's in some cases(Tom)
Shared library dependencies fixed (Tom)
Fixed glitches affecting GROUP BY in subselects(Tom)
Fix some compiler warnings (Tomoaki Nishiyama)
Add Win1250 (Czech) support (Pavel Behal)
    </programlisting>
   </para>
  </sect2>
 </sect1>

 <sect1 id="release-6-5">
  <title>Release 6.5</title>

  <note>
  <title>Release date</title>
  <simpara>1999-06-09</simpara>
  </note>

  <para>
   This release marks a major step in the development team's mastery of the source
   code we inherited from Berkeley.  You will see we are now easily adding
   major features, thanks to the increasing size and experience of our
   world-wide development team.
  </para>

  <para>
   Here is a brief summary of the more notable changes:

   <variablelist>
    <varlistentry>
     <term>
      Multiversion concurrency control(MVCC)
     </term>
     <listitem>
      <para>
       This removes our old table-level locking, and replaces it with
       a locking system that is superior to most commercial database
       systems.  In a traditional system, each row that is modified
       is locked until committed, preventing reads by other users.
       MVCC uses the natural multiversion nature of
       <productname>PostgreSQL</productname> to allow readers to
       continue reading consistent data during writer activity.
       Writers continue to use the compact pg_log transaction system.
       This is all performed without having to allocate a lock for
       every row like traditional database systems.  So, basically,
       we no longer are restricted by simple table-level locking; we
       have something better than row-level locking.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Hot backups from <application>pg_dump</application>
     </term>
     <listitem>
      <para>
       <application>pg_dump</application> takes advantage of the new
       MVCC features to give a consistent database dump/backup while
       the database stays online and available for queries.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Numeric data type
     </term>
     <listitem>
      <para>
       We now have a true numeric data type, with
       user-specified precision.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Temporary tables
     </term>
     <listitem>
      <para>
       Temporary tables are guaranteed to have unique names
       within a database session, and are destroyed on session exit.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      New SQL features
     </term>
     <listitem>
      <para>
       We now have CASE, INTERSECT, and EXCEPT statement
       support.  We have new LIMIT/OFFSET, SET TRANSACTION ISOLATION LEVEL,
       SELECT ... FOR UPDATE, and an improved LOCK TABLE command.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Speedups
     </term>
     <listitem>
      <para>
       We continue to speed up <productname>PostgreSQL</productname>,
       thanks to the variety of talents within our team.  We have
       sped up memory allocation, optimization, table joins, and row
       transfer routines.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Ports
     </term>
     <listitem>
      <para>
       We continue to expand our port list, this time including
       <systemitem class="osname">Windows NT</>/<systemitem>ix86</> and <systemitem class="osname">NetBSD</>/<systemitem>arm32</>.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Interfaces
     </term>
     <listitem>
      <para>
       Most interfaces have new versions, and existing functionality
       has been improved.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term>
      Documentation
     </term>
     <listitem>
      <para>
       New and updated material is present throughout the
       documentation. New <acronym>FAQ</acronym>s have been
       contributed for <systemitem class="osname">SGI</> and <systemitem class="osname">AIX</> platforms.
       The <citetitle>Tutorial</citetitle> has introductory information
       on <acronym>SQL</acronym> from Stefan Simkovics.
       For the <citetitle>User's Guide</citetitle>, there are
       reference pages covering the postmaster and more utility
       programs, and a new appendix
       contains details on date/time behavior.
       The <citetitle>Administrator's Guide</citetitle> has a new
       chapter on troubleshooting from Tom Lane.
       And the <citetitle>Programmer's Guide</citetitle> has a
       description of query processing, also from Stefan, and details
       on obtaining the <productname>PostgreSQL</productname> source
       tree via anonymous <productname>CVS</productname> and
       <productname>CVSup</productname>.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>

  <sect2>
   <title>Migration to Version 6.5</title>

   <para>
    A dump/restore using <application>pg_dump</application>
    is required for those wishing to migrate data from any
    previous release of <productname>PostgreSQL</productname>.
    <application>pg_upgrade</application> can <emphasis>not</emphasis>
    be used to upgrade to this release because the on-disk structure
    of the tables has changed compared to previous releases.
   </para>

   <para>
    The new Multiversion Concurrency Control (MVCC) features can
    give somewhat different behaviors in multiuser
    environments. <emphasis>Read and understand the following section
     to ensure that your existing applications will give you the
     behavior you need.</emphasis>
   </para>

   <sect3>
    <title>Multiversion Concurrency Control</title>

    <para>
     Because readers in 6.5 don't lock data, regardless of transaction
     isolation level, data read by one transaction can be overwritten by
     another. In other words, if a row is returned by
     <command>SELECT</command> it doesn't mean that this row really exists
     at the time it is returned (i.e. sometime after the statement or
     transaction began) nor that the row is protected from being deleted or
     updated by concurrent transactions before the current transaction does
     a commit or rollback.
    </para>

    <para>
     To ensure the actual existence of a row and protect it against
     concurrent updates one must use <command>SELECT FOR UPDATE</command> or
     an appropriate <command>LOCK TABLE</command> statement. This should be
     taken into account when porting applications from previous releases of
     <productname>PostgreSQL</productname> and other environments.
    </para>

    <para>
     Keep the above in mind if you are using
     <filename>contrib/refint.*</filename> triggers for
     referential integrity. Additional techniques are required now. One way is
     to use <command>LOCK parent_table IN SHARE ROW EXCLUSIVE MODE</command>
     command if a transaction is going to update/delete a primary key and
     use <command>LOCK parent_table IN SHARE MODE</command> command if a
     transaction is going to update/insert a foreign key.

     <note>
      <para>
       Note that if you run a transaction in SERIALIZABLE mode then you must
       execute the <command>LOCK</command> commands above before execution of any
       <acronym>DML</acronym> statement
       (<command>SELECT/INSERT/DELETE/UPDATE/FETCH/COPY_TO</command>) in the
       transaction.
      </para>
     </note>
    </para>

    <para>
     These inconveniences will disappear in the future
     when the ability to read dirty
     (uncommitted) data (regardless of isolation level) and true referential
     integrity will be implemented.
    </para>
   </sect3>
   </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Bug Fixes
---------
Fix text&lt;-&gt;float8 and text&lt;-&gt;float4 conversion functions(Thomas)
Fix for creating tables with mixed-case constraints(Billy)
Change exp()/pow() behavior to generate error on underflow/overflow(Jan)
Fix bug in pg_dump -z
Memory overrun cleanups(Tatsuo)
Fix for lo_import crash(Tatsuo)
Adjust handling of data type names to suppress double quotes(Thomas)
Use type coercion for matching columns and DEFAULT(Thomas)
Fix deadlock so it only checks once after one second of sleep(Bruce)
Fixes for aggregates and PL/pgsql(Hiroshi)
Fix for subquery crash(Vadim)
Fix for libpq function PQfnumber and case-insensitive names(Bahman Rafatjoo)
Fix for large object write-in-middle, no extra block, memory consumption(Tatsuo)
Fix for pg_dump -d or -D and  quote special characters in INSERT
Repair serious problems with dynahash(Tom)
Fix INET/CIDR portability problems
Fix problem with selectivity error in ALTER TABLE ADD COLUMN(Bruce)
Fix executor so mergejoin of different column types works(Tom)
Fix for Alpha OR selectivity bug
Fix OR index selectivity problem(Bruce)
Fix so \d shows proper length for char()/varchar()(Ryan)
Fix tutorial code(Clark)
Improve destroyuser checking(Oliver)
Fix for Kerberos(Rodney McDuff)
Fix for dropping database while dirty buffers(Bruce)
Fix so sequence nextval() can be case-sensitive(Bruce)
Fix !!= operator
Drop buffers before destroying database files(Bruce)
Fix case where executor evaluates functions twice(Tatsuo)
Allow sequence nextval actions to be case-sensitive(Bruce)
Fix optimizer indexing not working for negative numbers(Bruce)
Fix for memory leak in executor with fjIsNull
Fix for aggregate memory leaks(Erik Riedel)
Allow user name containing a dash to grant privileges
Cleanup of NULL in inet types
Clean up system table bugs(Tom)
Fix problems of PAGER and \? command(Masaaki Sakaida)
Reduce default multisegment file size limit to 1GB(Peter)
Fix for dumping of CREATE OPERATOR(Tom)
Fix for backward scanning of cursors(Hiroshi Inoue)
Fix for COPY FROM STDIN when using \i(Tom)
Fix for subselect is compared inside an expression(Jan)
Fix handling of error reporting while returning rows(Tom)
Fix problems with reference to array types(Tom,Jan)
Prevent UPDATE SET oid(Jan)
Fix pg_dump so -t option can handle case-sensitive tablenames
Fixes for GROUP BY in special cases(Tom, Jan)
Fix for memory leak in failed queries(Tom)
DEFAULT now supports mixed-case identifiers(Tom)
Fix for multisegment uses of DROP/RENAME table, indexes(Ole Gjerde)
Disable use of pg_dump with both -o and -d options(Bruce)
Allow pg_dump to properly dump group privileges(Bruce)
Fix GROUP BY in INSERT INTO table SELECT * FROM table2(Jan)
Fix for computations in views(Jan)
Fix for aggregates on array indexes(Tom)
Fix for DEFAULT handles single quotes in value requiring too many quotes
Fix security problem with non-super users importing/exporting large objects(Tom)
Rollback of transaction that creates table cleaned up properly(Tom)
Fix to allow long table and column names to generate proper serial names(Tom)

Enhancements
------------
Add "vacuumdb" utility
Speed up libpq by allocating memory better(Tom)
EXPLAIN all indexes used(Tom)
Implement CASE, COALESCE, NULLIF  expression(Thomas)
New pg_dump table output format(Constantin)
Add string min()/max() functions(Thomas)
Extend new type coercion techniques to aggregates(Thomas)
New moddatetime contrib(Terry)
Update to pgaccess 0.96(Constantin)
Add routines for single-byte "char" type(Thomas)
Improved substr() function(Thomas)
Improved multibyte handling(Tatsuo)
Multiversion concurrency control/MVCC(Vadim)
New Serialized mode(Vadim)
Fix for tables over 2gigs(Peter)
New SET TRANSACTION ISOLATION LEVEL(Vadim)
New LOCK TABLE IN ... MODE(Vadim)
Update ODBC driver(Byron)
New NUMERIC data type(Jan)
New SELECT FOR UPDATE(Vadim)
Handle "NaN" and "Infinity" for input values(Jan)
Improved date/year handling(Thomas)
Improved handling of backend connections(Magnus)
New options ELOG_TIMESTAMPS and USE_SYSLOG options for log files(Massimo)
New TCL_ARRAYS option(Massimo)
New INTERSECT and EXCEPT(Stefan)
New pg_index.indisprimary for primary key tracking(D'Arcy)
New pg_dump option to allow dropping of tables before creation(Brook)
Speedup of row output routines(Tom)
New READ COMMITTED isolation level(Vadim)
New TEMP tables/indexes(Bruce)
Prevent sorting if result is already sorted(Jan)
New memory allocation optimization(Jan)
Allow psql to do \p\g(Bruce)
Allow multiple rule actions(Jan)
Added LIMIT/OFFSET functionality(Jan)
Improve optimizer when joining a large number of tables(Bruce)
New intro to SQL from S. Simkovics' Master's Thesis (Stefan, Thomas)
New intro to backend processing from S. Simkovics' Master's Thesis (Stefan)
Improved int8 support(Ryan Bradetich, Thomas, Tom)
New routines to convert between int8 and text/varchar types(Thomas)
New bushy plans, where meta-tables are joined(Bruce)
Enable right-hand queries by default(Bruce)
Allow reliable maximum number of backends to be set at configure time
     (--with-maxbackends and postmaster switch (-N backends))(Tom)
GEQO default now 10 tables because of optimizer speedups(Tom)
Allow NULL=Var for MS-SQL portability(Michael, Bruce)
Modify contrib check_primary_key() so either "automatic" or "dependent"(Anand)
Allow psql \d on a view show query(Ryan)
Speedup for LIKE(Bruce)
Ecpg fixes/features, see src/interfaces/ecpg/ChangeLog file(Michael)
JDBC fixes/features, see src/interfaces/jdbc/CHANGELOG(Peter)
Make % operator have precedence like /(Bruce)
Add new postgres -O option to allow system table structure changes(Bruce)
Update contrib/pginterface/findoidjoins script(Tom)
Major speedup in vacuum of deleted rows with indexes(Vadim)
Allow non-SQL functions to run different versions based on arguments(Tom)
Add -E option that shows actual queries sent by \dt and friends(Masaaki Sakaida)
Add version number in start-up banners for psql(Masaaki Sakaida)
New contrib/vacuumlo removes large objects not referenced(Peter)
New initialization for table sizes so non-vacuumed tables perform better(Tom)
Improve error messages when a connection is rejected(Tom)
Support for arrays of char() and varchar() fields(Massimo)
Overhaul of hash code to increase reliability and performance(Tom)
Update to PyGreSQL 2.4(D'Arcy)
Changed debug options so -d4 and -d5 produce different node displays(Jan)
New pg_options: pretty_plan, pretty_parse, pretty_rewritten(Jan)
Better optimization statistics for system table access(Tom)
Better handling of non-default block sizes(Massimo)
Improve GEQO optimizer memory consumption(Tom)
UNION now supports ORDER BY of columns not in target list(Jan)
Major libpq++ improvements(Vince Vielhaber)
pg_dump now uses -z(ACL's) as default(Bruce)
backend cache, memory speedups(Tom)
have pg_dump do everything in one snapshot transaction(Vadim)
fix for large object memory leakage, fix for pg_dumping(Tom)
INET type now respects netmask for comparisons
Make VACUUM ANALYZE only use a readlock(Vadim)
Allow VIEWs on UNIONS(Jan)
pg_dump now can generate consistent snapshots on active databases(Vadim)

Source Tree Changes
-------------------
Improve port matching(Tom)
Portability fixes for SunOS
Add Windows NT backend port and enable dynamic loading(Magnus and Daniel Horak)
New port to Cobalt Qube(Mips) running Linux(Tatsuo)
Port to NetBSD/m68k(Mr. Mutsuki Nakajima)
Port to NetBSD/sun3(Mr. Mutsuki Nakajima)
Port to NetBSD/macppc(Toshimi Aoki)
Fix for tcl/tk configuration(Vince)
Removed CURRENT key word for rule queries(Jan)
NT dynamic loading now works(Daniel Horak)
Add ARM32 support(Andrew McMurry)
Better support for HP-UX 11 and UnixWare
Improve file handling to be more uniform, prevent file descriptor leak(Tom)
New install commands for plpgsql(Jan)
    </programlisting>
   </para>
  </sect2>
 </sect1>


<sect1 id="release-6-4-2">
<title>Release 6.4.2</title>

  <note>
  <title>Release date</title>
  <simpara>1998-12-20</simpara>
  </note>

<para>
The 6.4.1 release was improperly packaged.  This also has one additional
bug fix.
</para>


<sect2>
<title>Migration to Version 6.4.2</title>

<para>
A dump/restore is <emphasis>not</emphasis> required for those running
6.4.*.
</para>
</sect2>
<sect2>
<title>Changes</title>

<para>
<programlisting>
Fix for datetime constant problem on some platforms(Thomas)
</programlisting>
</para>
</sect2>
</sect1>



<sect1 id="release-6-4-1">
<title>Release 6.4.1</title>

  <note>
  <title>Release date</title>
  <simpara>1998-12-18</simpara>
  </note>

<para>
This is basically a cleanup release for 6.4.  We have fixed a variety of
problems reported by 6.4 users.
</para>


<sect2>
<title>Migration to Version 6.4.1</title>

<para>
A dump/restore is <emphasis>not</emphasis> required for those running
6.4.
</para>
</sect2>
<sect2>
<title>Changes</title>

<para>
<programlisting>
Add pg_dump -N flag to force double quotes around identifiers.  This is
       the default(Thomas)
Fix for NOT in where clause causing crash(Bruce)
EXPLAIN VERBOSE coredump fix(Vadim)
Fix shared-library problems on Linux
Fix test for table existence to allow mixed-case and whitespace in
       the table name(Thomas)
Fix a couple of pg_dump bugs
Configure matches template/.similar entries better(Tom)
Change builtin function names from SPI_* to spi_*
OR WHERE clause fix(Vadim)
Fixes for mixed-case table names(Billy)
contrib/linux/postgres.init.csh/sh fix(Thomas)
libpq memory overrun fix
SunOS fixes(Tom)
Change exp() behavior to generate error on underflow(Thomas)
pg_dump fixes for memory leak, inheritance constraints, layout change
update pgaccess to 0.93
Fix prototype for 64-bit platforms
Multibyte fixes(Tatsuo)
New ecpg man page
Fix memory overruns(Tatsuo)
Fix for lo_import() crash(Bruce)
Better search for install program(Tom)
Timezone fixes(Tom)
HP-UX fixes(Tom)
Use implicit type coercion for matching DEFAULT values(Thomas)
Add routines to help with single-byte (internal) character type(Thomas)
Compilation of libpq for Windows fixes(Magnus)
Upgrade to PyGreSQL 2.2(D'Arcy)
</programlisting>
</para>
</sect2>
</sect1>



<sect1 id="release-6-4">
<title>Release 6.4</title>

  <note>
  <title>Release date</title>
  <simpara>1998-10-30</simpara>
  </note>

<para>
There are <emphasis>many</emphasis> new features and improvements in this release.
Thanks to our developers and maintainers, nearly every aspect of the system
has received some attention since the previous release.
Here is a brief, incomplete summary:

<itemizedlist>
<listitem>
<para>
Views and rules are now functional thanks to extensive new code in the
rewrite rules system from Jan Wieck. He also wrote a chapter on it
for the <citetitle>Programmer's Guide</citetitle>.
</para>
</listitem>
<listitem>
<para>
Jan also contributed a second procedural language, <application>PL/pgSQL</application>, to go with the
original <application>PL/pgTCL</application> procedural language he contributed last release.
</para>
</listitem>

<listitem>
<para>
We have optional multiple-byte character set support from Tatsuo Ishii
to complement our existing locale support.
</para>
</listitem>

<listitem>
<para>
Client/server communications has been cleaned up, with better support for
asynchronous messages and interrupts thanks to Tom Lane.
</para>
</listitem>

<listitem>
<para>
The parser will now perform automatic type coercion to match arguments
to available operators and functions, and to match columns and expressions
with target columns. This uses a generic mechanism which supports
the type extensibility features of <productname>PostgreSQL</productname>.
There is a new chapter in the <citetitle>User's Guide</citetitle>
which covers this topic.
</para>
</listitem>

<listitem>
<para>
Three new data types have been added.
Two types, <type>inet</type> and <type>cidr</type>, support various forms
of IP network, subnet, and machine addressing. There is now an 8-byte integer
type available on some platforms. See the chapter on data types
in the <citetitle>User's Guide</citetitle> for details.
A fourth type, <type>serial</type>, is now supported by the parser as an
amalgam of the <type>int4</type> type, a sequence, and a unique index.
</para>
</listitem>

<listitem>
<para>
Several more <acronym>SQL92</acronym>-compatible syntax features have been
added, including <command>INSERT DEFAULT VALUES</command>
</para>
</listitem>

<listitem>
<para>
The automatic configuration and installation system has received some
attention, and should be more robust for more platforms than it has ever
been.
</para>
</listitem>

</itemizedlist>
</para>

<sect2>
<title>Migration to Version 6.4</title>

<para>
A dump/restore using <application>pg_dump</application>
or <application>pg_dumpall</application>
is required for those wishing to migrate data from any
previous release of <productname>PostgreSQL</productname>.
</para>
</sect2>

  <sect2>
<title>Changes</title>

   <para>
    <programlisting>
Bug Fixes
---------
Fix for a tiny memory leak in PQsetdb/PQfinish(Bryan)
Remove char2-16 data types, use char/varchar(Darren)
Pqfn not handles a NOTICE message(Anders)
Reduced busywaiting overhead for spinlocks with many backends (dg)
Stuck spinlock detection (dg)
Fix up "ISO-style" timespan decoding and encoding(Thomas)
Fix problem with table drop after rollback of transaction(Vadim)
Change error message and remove non-functional update message(Vadim)
Fix for COPY array checking
Fix for SELECT 1 UNION SELECT NULL
Fix for buffer leaks in large object calls(Pascal)
Change owner from oid to int4 type(Bruce)
Fix a bug in the oracle compatibility functions btrim() ltrim() and rtrim()
Fix for shared invalidation cache overflow(Massimo)
Prevent file descriptor leaks in failed COPY's(Bruce)
Fix memory leak in libpgtcl's pg_select(Constantin)
Fix problems with username/passwords over 8 characters(Tom)
Fix problems with handling of asynchronous NOTIFY in backend(Tom)
Fix of many bad system table entries(Tom)

Enhancements
------------
Upgrade ecpg and ecpglib,see src/interfaces/ecpc/ChangeLog(Michael)
Show the index used in an EXPLAIN(Zeugswetter)
EXPLAIN  invokes  rule system and shows plan(s) for rewritten queries(Jan)
Multibyte awareness of many data types and functions, via configure(Tatsuo)
New configure --with-mb option(Tatsuo)
New initdb --pgencoding option(Tatsuo)
New createdb -E multibyte option(Tatsuo)
Select version(); now returns PostgreSQL version(Jeroen)
libpq now allows asynchronous clients(Tom)
Allow cancel from client of backend query(Tom)
psql now cancels query with Control-C(Tom)
libpq users need not issue dummy queries to get NOTIFY messages(Tom)
NOTIFY now sends sender's PID, so you can tell whether it was your own(Tom)
PGresult struct now includes associated error message, if any(Tom)
Define "tz_hour" and "tz_minute" arguments to date_part()(Thomas)
Add routines to convert between varchar and bpchar(Thomas)
Add routines to allow sizing of varchar and bpchar into target columns(Thomas)
Add bit flags to support timezonehour and minute in data retrieval(Thomas)
Allow more variations on valid floating point numbers (e.g. ".1", "1e6")(Thomas)
Fixes for unary minus parsing with leading spaces(Thomas)
Implement TIMEZONE_HOUR, TIMEZONE_MINUTE per SQL92 specs(Thomas)
Check for and properly ignore FOREIGN KEY column constraints(Thomas)
Define USER as synonym for CURRENT_USER per SQL92 specs(Thomas)
Enable HAVING clause but no fixes elsewhere yet.
Make "char" type a synonym for "char(1)" (actually implemented as bpchar)(Thomas)
Save string type if specified for DEFAULT clause handling(Thomas)
Coerce operations involving different data types(Thomas)
Allow some index use for columns of different types(Thomas)
Add capabilities for automatic type conversion(Thomas)
Cleanups for large objects, so file is truncated on open(Peter)
Readline cleanups(Tom)
Allow psql  \f \ to make spaces as delimiter(Bruce)
Pass pg_attribute.atttypmod to the frontend for column field lengths(Tom,Bruce)
Msql compatibility library in /contrib(Aldrin)
Remove the requirement that ORDER/GROUP BY clause identifiers be
included in the target list(David)
Convert columns to match columns in UNION clauses(Thomas)
Remove fork()/exec() and only do fork()(Bruce)
Jdbc cleanups(Peter)
Show backend status on ps command line(only works on some platforms)(Bruce)
Pg_hba.conf now has a sameuser option in the database field
Make lo_unlink take oid param, not int4
New DISABLE_COMPLEX_MACRO for compilers that cannot handle our macros(Bruce)
Libpgtcl now handles NOTIFY as a Tcl event, need not send dummy queries(Tom)
libpgtcl cleanups(Tom)
Add -error option to libpgtcl's pg_result command(Tom)
New locale patch, see docs/README/locale(Oleg)
Fix for pg_dump so CONSTRAINT and CHECK syntax is correct(ccb)
New contrib/lo code for large object orphan removal(Peter)
New psql command "SET CLIENT_ENCODING TO 'encoding'" for multibytes
feature, see /doc/README.mb(Tatsuo)
contrib/noupdate code to revoke update permission on a column
libpq can now be compiled on Windows(Magnus)
Add PQsetdbLogin() in libpq
New 8-byte integer type, checked by configure for OS support(Thomas)
Better support for quoted table/column names(Thomas)
Surround table and column names with double-quotes in pg_dump(Thomas)
PQreset() now works with passwords(Tom)
Handle case of GROUP BY target list column number out of range(David)
Allow UNION in subselects
Add auto-size to screen to \d? commands(Bruce)
Use UNION to show all \d? results in one query(Bruce)
Add \d? field search feature(Bruce)
Pg_dump issues fewer \connect requests(Tom)
Make pg_dump -z flag work better, document it in manual page(Tom)
Add HAVING clause with full support for subselects and unions(Stephan)
Full text indexing routines in contrib/fulltextindex(Maarten)
Transaction ids now stored in shared memory(Vadim)
New PGCLIENTENCODING when issuing COPY command(Tatsuo)
Support for SQL92 syntax "SET NAMES"(Tatsuo)
Support for LATIN2-5(Tatsuo)
Add UNICODE regression test case(Tatsuo)
Lock manager cleanup, new locking modes for LLL(Vadim)
Allow index use with OR clauses(Bruce)
Allows "SELECT NULL ORDER BY 1;"
Explain VERBOSE prints the plan, and now pretty-prints the plan to
the postmaster log file(Bruce)
Add indexes display to \d command(Bruce)
Allow GROUP BY on functions(David)
New pg_class.relkind for large objects(Bruce)
New way to send libpq NOTICE messages to a different location(Tom)
New \w write command to psql(Bruce)
New /contrib/findoidjoins scans oid columns to find join relationships(Bruce)
Allow binary-compatible indexes to be considered when checking for valid
Indexes for restriction clauses containing a constant(Thomas)
New ISBN/ISSN code in /contrib/isbn_issn
Allow NOT LIKE, IN, NOT IN, BETWEEN, and NOT BETWEEN constraint(Thomas)
New rewrite system fixes many problems with rules and views(Jan)
       * Rules on relations work
       * Event qualifications on insert/update/delete work
       * New OLD variable to reference CURRENT, CURRENT will be remove in future
       * Update rules can reference NEW and OLD in rule qualifications/actions
       * Insert/update/delete rules on views work
       * Multiple rule actions are now supported, surrounded by parentheses
       * Regular users can create views/rules on tables they have RULE permits
       * Rules and views inherit the privileges of the creator
       * No rules at the column level
       * No UPDATE NEW/OLD rules
       * New pg_tables, pg_indexes, pg_rules and pg_views system views
       * Only a single action on SELECT rules
       * Total rewrite overhaul, perhaps for 6.5
       * handle subselects
       * handle aggregates on views
       * handle insert into select from view works
System indexes are now multikey(Bruce)
Oidint2, oidint4, and oidname types are removed(Bruce)
Use system cache for more system table lookups(Bruce)
New backend programming language PL/pgSQL in backend/pl(Jan)
New SERIAL data type, auto-creates sequence/index(Thomas)
Enable assert checking without a recompile(Massimo)
User lock enhancements(Massimo)
New setval() command to set sequence value(Massimo)
Auto-remove unix socket file on start-up if no postmaster running(Massimo)
Conditional trace package(Massimo)
New UNLISTEN command(Massimo)
psql and libpq now compile under Windows using win32.mak(Magnus)
Lo_read no longer stores trailing NULL(Bruce)
Identifiers are now truncated to 31 characters internally(Bruce)
Createuser options now available on the command line
Code for 64-bit integer supported added, configure tested, int8 type(Thomas)
Prevent file descriptor leaf from failed COPY(Bruce)
New pg_upgrade command(Bruce)
Updated /contrib directories(Massimo)
New CREATE TABLE DEFAULT VALUES statement available(Thomas)
New INSERT INTO TABLE DEFAULT VALUES statement available(Thomas)
New DECLARE and FETCH feature(Thomas)
libpq's internal structures now not exported(Tom)
Allow up to 8 key indexes(Bruce)
Remove ARCHIVE key word, that is no longer used(Thomas)
pg_dump -n flag to suppress quotes around indentifiers
disable system columns for views(Jan)
new INET and CIDR types for network addresses(TomH, Paul)
no more double quotes in psql output
pg_dump now dumps views(Terry)
new SET QUERY_LIMIT(Tatsuo,Jan)

Source Tree Changes
-------------------
/contrib cleanup(Jun)
Inline some small functions called for every row(Bruce)
Alpha/linux fixes
HP-UX cleanups(Tom)
Multibyte regression tests(Soonmyung.)
Remove --disabled options from configure
Define PGDOC to use POSTGRESDIR by default
Make regression optional
Remove extra braces code to pgindent(Bruce)
Add bsdi shared library support(Bruce)
New --without-CXX support configure option(Brook)
New FAQ_CVS
Update backend flowchart in tools/backend(Bruce)
Change atttypmod from int16 to int32(Bruce, Tom)
Getrusage() fix for platforms that do not have it(Tom)
Add PQconnectdb, PGUSER, PGPASSWORD to libpq man page
NS32K platform fixes(Phil Nelson, John Buller)
SCO 7/UnixWare 2.x fixes(Billy,others)
Sparc/Solaris 2.5 fixes(Ryan)
Pgbuiltin.3 is obsolete, move to doc files(Thomas)
Even more documentation(Thomas)
Nextstep support(Jacek)
Aix support(David)
pginterface manual page(Bruce)
shared libraries all have version numbers
merged all OS-specific shared library defines into one file
smarter TCL/TK configuration checking(Billy)
smarter perl configuration(Brook)
configure uses supplied install-sh if no install script found(Tom)
new Makefile.shlib for shared library configuration(Tom)
</programlisting>
</para>
</sect2>
</sect1>

<sect1 id="release-6-3-2">
<title>Release 6.3.2</title>

  <note>
  <title>Release date</title>
  <simpara>1998-04-07</simpara>
  </note>

<para>
This is a bug-fix release for 6.3.x.
Refer to the release notes for version 6.3 for a more complete summary of new features.
</para>
<para>
Summary:

<itemizedlist>
<listitem>
<para>
Repairs automatic configuration support for some platforms, including Linux,
from breakage inadvertently introduced in version 6.3.1.
</para>
</listitem>

<listitem>
<para>
Correctly handles function calls on the left side of BETWEEN and LIKE clauses.
</para>
</listitem>

</itemizedlist>
</para>
<para>
A dump/restore is NOT required for those running 6.3 or 6.3.1.  A
<literal>make distclean</>, <literal>make</>, and <literal>make install</> is all that is required.
This last step should be performed while the postmaster is not running.
You should re-link any custom applications that use <productname>PostgreSQL</productname> libraries.
</para>
<para>
For upgrades from pre-6.3 installations,
refer to the installation and migration instructions for version 6.3.
</para>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Configure detection improvements for tcl/tk(Brook Milligan, Alvin)
Manual page improvements(Bruce)
BETWEEN and LIKE fix(Thomas)
fix for psql \connect used by pg_dump(Oliver Elphick)
New odbc driver
pgaccess, version 0.86
qsort removed, now uses libc version, cleanups(Jeroen)
fix for buffer over-runs detected(Maurice Gittens)
fix for buffer overrun in libpgtcl(Randy Kunkee)
fix for UNION with DISTINCT or ORDER BY(Bruce)
gettimeofday configure check(Doug Winterburn)
Fix "indexes not used" bug(Vadim)
docs additions(Thomas)
Fix for backend memory leak(Bruce)
libreadline cleanup(Erwan MAS)
Remove DISTDIR(Bruce)
Makefile dependency cleanup(Jeroen van Vianen)
ASSERT fixes(Bruce)
    </programlisting>
   </para>
  </sect2>
 </sect1>

 <sect1 id="release-6-3-1">
  <title>Release 6.3.1</title>

  <note>
  <title>Release date</title>
  <simpara>1998-03-23</simpara>
  </note>

  <para>
   Summary:

<itemizedlist>
<listitem>
<para>
Additional support for multibyte character sets.
</para>
</listitem>

<listitem>
<para>
Repair byte ordering for mixed-endian clients and servers.
</para>
</listitem>

<listitem>
<para>
Minor updates to allowed SQL syntax.
</para>
</listitem>

<listitem>
<para>
Improvements to the configuration autodetection for installation.
</para>
</listitem>

</itemizedlist>
</para>
<para>
A dump/restore is NOT required for those running 6.3.  A
<literal>make distclean</>, <literal>make</>, and <literal>make install</> is all that is required.
This last step should be performed while the postmaster is not running.
You should re-link any custom applications that use <productname>PostgreSQL</productname> libraries.
</para>
<para>
For upgrades from pre-6.3 installations,
refer to the installation and migration instructions for version 6.3.
</para>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
ecpg cleanup/fixes, now version 1.1(Michael Meskes)
pg_user cleanup(Bruce)
large object fix for pg_dump and tclsh (alvin)
LIKE fix for multiple adjacent underscores
fix for redefining builtin functions(Thomas)
ultrix4 cleanup
upgrade to pg_access 0.83
updated CLUSTER manual page
multibyte character set support, see doc/README.mb(Tatsuo)
configure --with-pgport fix
pg_ident fix
big-endian fix for backend communications(Kataoka)
SUBSTR() and substring() fix(Jan)
several jdbc fixes(Peter)
libpgtcl improvements, see libptcl/README(Randy Kunkee)
Fix for "Datasize = 0" error(Vadim)
Prevent \do from wrapping(Bruce)
Remove duplicate Russian character set entries
Sunos4 cleanup
Allow optional TABLE key word in LOCK and SELECT INTO(Thomas)
CREATE SEQUENCE options to allow a negative integer(Thomas)
Add "PASSWORD" as an allowed column identifier(Thomas)
Add checks for UNION target fields(Bruce)
Fix Alpha port(Dwayne Bailey)
Fix for text arrays containing quotes(Doug Gibson)
Solaris compile fix(Albert Chin-A-Young)
Better identify tcl and tk libs and includes(Bruce)
    </programlisting>
   </para>
  </sect2>
 </sect1>

 <sect1 id="release-6-3">
  <title>Release 6.3</title>

  <note>
  <title>Release date</title>
  <simpara>1998-03-01</simpara>
  </note>

  <para>
   There are <emphasis>many</emphasis> new features and improvements in this release.
   Here is a brief, incomplete summary:

   <itemizedlist>
    <listitem>
     <para>
      Many new SQL features, including
      full <acronym>SQL92</acronym> subselect capability
      (everything is here but target-list subselects).
     </para>
    </listitem>

    <listitem>
     <para>
      Support for client-side environment variables to specify time zone and date style.
     </para>
    </listitem>

    <listitem>
     <para>
      Socket interface for client/server connection. This is the default now
      so you might need to start <application>postmaster</application> with the
      <option>-i</option> flag.
     </para>
    </listitem>

    <listitem>
     <para>
      Better password authorization mechanisms. Default table privileges have changed.
     </para>
    </listitem>

    <listitem>
     <para>
      Old-style <firstterm>time travel</firstterm>
      has been removed. Performance has been improved.
     </para>
    </listitem>
   </itemizedlist>
  </para>

  <note>
   <para>
    Bruce Momjian wrote the following notes to introduce the new release.
   </para>
  </note>

  <para>
   There are some general 6.3 issues that I want to mention.  These are
   only the big items that cannot be described in one sentence.  A review
   of the detailed changes list is still needed.
  </para>
  <para>
   First, we now have subselects.  Now that we have them, I would like to
   mention that without subselects, SQL is a very limited language.
   Subselects are a major feature, and you should review your code for
   places where subselects provide a better solution for your queries.  I
   think you will find that there are more uses for subselects than you might
   think.  Vadim has put us on the big SQL map with subselects, and fully
   functional ones too.  The only thing you cannot do with subselects is to
   use them in the target list.
  </para>
  <para>
   Second, 6.3 uses Unix domain sockets rather than TCP/IP by default.  To
   enable connections from other machines, you have to use the new
   postmaster -i option, and of course edit <filename>pg_hba.conf</filename>.  Also, for this
   reason, the format of <filename>pg_hba.conf</filename> has changed.
  </para>
  <para>
   Third, <type>char()</type> fields will now allow faster access than <type>varchar()</type> or
   <type>text</type>. Specifically, the <type>text</> and <type>varchar()</type> have a penalty for access to
   any columns after the first column of this type.  <type>char()</type> used to also
   have this access penalty, but it no longer does.  This might suggest that
   you redesign some of your tables, especially if you have short character
   columns that you have defined as <type>varchar()</type> or <type>text</type>.  This and other
   changes make 6.3 even faster than earlier releases.
  </para>
  <para>
   We now have passwords definable independent of any Unix file.  There are
   new SQL USER commands.
   See the <citetitle>Administrator's Guide</citetitle> for more
   information.  There is a new table, pg_shadow, which is used to store
   user information and user passwords, and it by default only SELECT-able
   by the <systemitem>postgres</systemitem> super-user.  pg_user is now a view of pg_shadow, and is
   SELECT-able by PUBLIC.  You should keep using pg_user in your
   application without changes.
  </para>
  <para>
   User-created tables now no longer have SELECT privilege to PUBLIC by
   default.  This was done because the ANSI standard requires it.  You can
   of course GRANT any privileges you want after the table is created.
   System tables continue to be SELECT-able by PUBLIC.
  </para>
  <para>
   We also have real deadlock detection code.  No more sixty-second
   timeouts.  And the new locking code implements a <acronym>FIFO</acronym> better, so there
   should be less resource starvation during heavy use.
  </para>
  <para>
   Many complaints have been made about inadequate documentation in previous
   releases.  Thomas has put much effort into many new manuals for this
   release.  Check out the doc/ directory.
  </para>
  <para>
   For performance reasons, time travel is gone, but can be implemented
   using triggers (see <filename>pgsql/contrib/spi/README</filename>).  Please check out the new
   \d command for types, operators, etc.  Also, views have their own
   privileges now, not based on the underlying tables, so privileges on
   them have to be set separately.  Check <filename>/pgsql/interfaces</filename> for some new
   ways to talk to <productname>PostgreSQL</productname>.
  </para>
  <para>
   This is the first release that really required an explanation for
   existing users.  In many ways, this was necessary because the new
   release removes many limitations, and the work-arounds people were using
   are no longer needed.
  </para>

  <sect2>
   <title>Migration to Version 6.3</title>

   <para>
    A dump/restore using <application>pg_dump</application>
    or <application>pg_dumpall</application>
    is required for those wishing to migrate data from any
    previous release of <productname>PostgreSQL</productname>.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Bug Fixes
---------
Fix binary cursors broken by MOVE implementation(Vadim)
Fix for tcl library crash(Jan)
Fix for array handling, from Gerhard Hintermayer
Fix acl error, and remove duplicate pqtrace(Bruce)
Fix psql \e for empty file(Bruce)
Fix for textcat on varchar() fields(Bruce)
Fix for DBT Sendproc (Zeugswetter Andres)
Fix vacuum analyze syntax problem(Bruce)
Fix for international identifiers(Tatsuo)
Fix aggregates on inherited tables(Bruce)
Fix substr() for out-of-bounds data
Fix for select 1=1 or 2=2, select 1=1 and 2=2, and select sum(2+2)(Bruce)
Fix notty output to show status result.  -q option still turns it off(Bruce)
Fix for count(*), aggs with views and multiple tables and sum(3)(Bruce)
Fix cluster(Bruce)
Fix for PQtrace start/stop several times(Bruce)
Fix a variety of locking problems like newer lock waiters getting
       lock before older waiters, and having readlock people not share
       locks if a writer is waiting for a lock, and waiting writers not
       getting priority over waiting readers(Bruce)
Fix crashes in psql when executing queries from external files(James)
Fix problem with multiple order by columns, with the first one having
       NULL values(Jeroen)
Use correct hash table support functions for float8 and int4(Thomas)
Re-enable JOIN= option in CREATE OPERATOR statement (Thomas)
Change precedence for boolean operators to match expected behavior(Thomas)
Generate elog(ERROR) on over-large integer(Bruce)
Allow multiple-argument functions in constraint clauses(Thomas)
Check boolean input literals for 'true','false','yes','no','1','0'
       and throw elog(ERROR) if unrecognized(Thomas)
Major large objects fix
Fix for GROUP BY showing duplicates(Vadim)
Fix for index scans in MergeJoin(Vadim)

Enhancements
------------
Subselects with EXISTS, IN, ALL, ANY key words (Vadim, Bruce, Thomas)
New User Manual(Thomas, others)
Speedup by inlining some frequently-called functions
Real deadlock detection, no more timeouts(Bruce)
Add SQL92 "constants" CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP,
       CURRENT_USER(Thomas)
Modify constraint syntax to be SQL92-compliant(Thomas)
Implement SQL92 PRIMARY KEY and UNIQUE clauses using indexes(Thomas)
Recognize SQL92 syntax for FOREIGN KEY. Throw elog notice(Thomas)
Allow NOT NULL UNIQUE constraint clause (each allowed separately before)(Thomas)
Allow PostgreSQL-style casting ("::") of non-constants(Thomas)
Add support for SQL3 TRUE and FALSE boolean constants(Thomas)
Support SQL92 syntax for IS TRUE/IS FALSE/IS NOT TRUE/IS NOT FALSE(Thomas)
Allow shorter strings for boolean literals (e.g. "t", "tr", "tru")(Thomas)
Allow SQL92 delimited identifiers(Thomas)
Implement SQL92 binary and hexadecimal string decoding (b'10' and x'1F')(Thomas)
Support SQL92 syntax for type coercion of literal strings
       (e.g. "DATETIME 'now'")(Thomas)
Add conversions for int2, int4, and OID types to and from text(Thomas)
Use shared lock when building indexes(Vadim)
Free memory allocated for an user query inside transaction block after
       this query is done, was turned off in &lt;= 6.2.1(Vadim)
New SQL statement CREATE PROCEDURAL LANGUAGE(Jan)
New <productname>PostgreSQL</productname> Procedural Language (PL) backend interface(Jan)
Rename pg_dump -H option to -h(Bruce)
Add Java support for passwords, European dates(Peter)
Use indexes for LIKE and ~, !~ operations(Bruce)
Add hash functions for datetime and timespan(Thomas)
Time Travel removed(Vadim, Bruce)
Add paging for \d and \z, and fix \i(Bruce)
Add Unix domain socket support to backend and to frontend library(Goran)
Implement CREATE DATABASE/WITH LOCATION and initlocation utility(Thomas)
Allow more SQL92 and/or <productname>PostgreSQL</productname> reserved words as column identifiers(Thomas)
Augment support for SQL92 SET TIME ZONE...(Thomas)
SET/SHOW/RESET TIME ZONE uses TZ backend environment variable(Thomas)
Implement SET keyword = DEFAULT and SET TIME ZONE DEFAULT(Thomas)
Enable SET TIME ZONE using TZ environment variable(Thomas)
Add PGDATESTYLE environment variable to frontend and backend initialization(Thomas)
Add PGTZ, PGCOSTHEAP, PGCOSTINDEX, PGRPLANS, PGGEQO
       frontend library initialization environment variables(Thomas)
Regression tests time zone automatically set with "setenv PGTZ PST8PDT"(Thomas)
Add pg_description table for info on tables, columns, operators, types, and
       aggregates(Bruce)
Increase 16 char limit on system table/index names to 32 characters(Bruce)
Rename system indexes(Bruce)
Add 'GERMAN' option to SET DATESTYLE(Thomas)
Define an "ISO-style" timespan output format with "hh:mm:ss" fields(Thomas)
Allow fractional values for delta times (e.g. '2.5 days')(Thomas)
Validate numeric input more carefully for delta times(Thomas)
Implement day of year as possible input to date_part()(Thomas)
Define timespan_finite() and text_timespan() functions(Thomas)
Remove archive stuff(Bruce)
Allow for a pg_password authentication database that is separate from
       the system password file(Todd)
Dump ACLs, GRANT, REVOKE privileges(Matt)
Define text, varchar, and bpchar string length functions(Thomas)
Fix Query handling for inheritance, and cost computations(Bruce)
Implement CREATE TABLE/AS SELECT (alternative to SELECT/INTO)(Thomas)
Allow NOT, IS NULL, IS NOT NULL in constraints(Thomas)
Implement UNIONs for SELECT(Bruce)
Add UNION, GROUP, DISTINCT to INSERT(Bruce)
varchar() stores only necessary bytes on disk(Bruce)
Fix for BLOBs(Peter)
Mega-Patch for JDBC...see README_6.3 for list of changes(Peter)
Remove unused "option" from PQconnectdb()
New LOCK command and lock manual page describing deadlocks(Bruce)
Add new psql \da, \dd, \df, \do, \dS, and \dT commands(Bruce)
Enhance psql \z to show sequences(Bruce)
Show NOT NULL and DEFAULT in psql \d table(Bruce)
New psql .psqlrc file start-up(Andrew)
Modify sample start-up script in contrib/linux to show syslog(Thomas)
New types for IP and MAC addresses in contrib/ip_and_mac(TomH)
Unix system time conversions with date/time types in contrib/unixdate(Thomas)
Update of contrib stuff(Massimo)
Add Unix socket support to DBD::Pg(Goran)
New python interface (PyGreSQL 2.0)(D'Arcy)
New frontend/backend protocol has a version number, network byte order(Phil)
Security features in pg_hba.conf enhanced and documented, many cleanups(Phil)
CHAR() now faster access than VARCHAR() or TEXT
ecpg embedded SQL preprocessor
Reduce system column overhead(Vadmin)
Remove pg_time table(Vadim)
Add pg_type attribute to identify types that need length (bpchar, varchar)
Add report of offending line when COPY command fails
Allow VIEW privileges to be set separately from the underlying tables.
       For security, use GRANT/REVOKE on views as appropriate(Jan)
Tables now have no default GRANT SELECT TO PUBLIC.  You must
       explicitly grant such privileges.
Clean up tutorial examples(Darren)

Source Tree Changes
-------------------
Add new html development tools, and flow chart in /tools/backend
Fix for SCO compiles
Stratus computer port Robert Gillies
Added support for shlib for BSD44_derived &amp; i386_solaris
Make configure more automated(Brook)
Add script to check regression test results
Break parser functions into smaller files, group together(Bruce)
Rename heap_create to heap_create_and_catalog, rename heap_creatr
       to heap_create()(Bruce)
Sparc/Linux patch for locking(TomS)
Remove PORTNAME and reorganize port-specific stuff(Marc)
Add optimizer README file(Bruce)
Remove some recursion in optimizer and clean up some code there(Bruce)
Fix for NetBSD locking(Henry)
Fix for libptcl make(Tatsuo)
AIX patch(Darren)
Change IS TRUE, IS FALSE, ... to expressions using "=" rather than
       function calls to istrue() or isfalse() to allow optimization(Thomas)
Various fixes NetBSD/Sparc related(TomH)
Alpha linux locking(Travis,Ryan)
Change elog(WARN) to elog(ERROR)(Bruce)
FAQ for FreeBSD(Marc)
Bring in the PostODBC source tree as part of our standard distribution(Marc)
A minor patch for HP/UX 10 vs 9(Stan)
New pg_attribute.atttypmod for type-specific info like varchar length(Bruce)
UnixWare patches(Billy)
New i386 'lock' for spinlock asm(Billy)
Support for multiplexed backends is removed
Start an OpenBSD port
Start an AUX port
Start a Cygnus port
Add string functions to regression suite(Thomas)
Expand a few function names formerly truncated to 16 characters(Thomas)
Remove un-needed malloc() calls and replace with palloc()(Bruce)
</programlisting>
</para>
</sect2>
</sect1>

<sect1 id="release-6-2-1">
<title>Release 6.2.1</title>

  <note>
  <title>Release date</title>
  <simpara>1997-10-17</simpara>
  </note>

<para>
6.2.1 is a bug-fix and usability release on 6.2.
</para>
<para>
Summary:

<itemizedlist>
<listitem>
<para>
Allow strings to span lines, per <acronym>SQL92</acronym>.
</para>
</listitem>

<listitem>
<para>
Include example trigger function for inserting user names on table updates.
</para>
</listitem>

</itemizedlist>
</para>
<para>
This is a minor bug-fix release on 6.2.
For upgrades from pre-6.2 systems, a full dump/reload is required.
Refer to the 6.2 release notes for instructions.
</para>

<sect2>
<title>Migration from version 6.2 to version 6.2.1</title>

<para>
This is a minor bug-fix release. A dump/reload is not required from version 6.2,
but is required from any release prior to 6.2.
</para>
<para>
In upgrading from version 6.2, if you choose to dump/reload you will find that
avg(money) is now calculated correctly. All other bug fixes take effect
upon updating the executables.
</para>
<para>
Another way to avoid dump/reload is to use the following SQL command
from <command>psql</command> to update the existing system table:

<programlisting>
 update pg_aggregate set aggfinalfn = 'cash_div_flt8'
  where aggname = 'avg' and aggbasetype = 790;
</programlisting>
</para>
<para>
This will need to be done to every existing database, including template1.
</para>
</sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Allow TIME and TYPE column names(Thomas)
Allow larger range of true/false as boolean values(Thomas)
Support output of "now" and "current"(Thomas)
Handle DEFAULT with INSERT of NULL properly(Vadim)
Fix for relation reference counts problem in buffer manager(Vadim)
Allow strings to span lines, like ANSI(Thomas)
Fix for backward cursor with ORDER BY(Vadim)
Fix avg(cash) computation(Thomas)
Fix for specifying a column twice in ORDER/GROUP BY(Vadim)
Documented new libpq function to return affected rows, PQcmdTuples(Bruce)
Trigger function for inserting user names for INSERT/UPDATE(Brook Milligan)
    </programlisting>
   </para>
  </sect2>
 </sect1>

<sect1 id="release-6-2">
<title>Release 6.2</title>

  <note>
  <title>Release date</title>
  <simpara>1997-10-02</simpara>
  </note>

<para>
A dump/restore is required for those wishing to migrate data from
previous releases of <productname>PostgreSQL</productname>.
</para>

<sect2>
<title>Migration from version 6.1 to version 6.2</title>

<para>
This migration requires a complete dump of the 6.1 database and a
restore of the database in 6.2.
</para>
<para>
Note that the <command>pg_dump</command> and <command>pg_dumpall</command> utility from 6.2 should be used
to dump the 6.1 database.
</para>
</sect2>

<sect2>
<title>Migration from version 1.<replaceable>x</> to version 6.2</title>

<para>
Those migrating from earlier 1.* releases should first upgrade to 1.09
because the COPY output format was improved from the 1.02 release.
</para>
</sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Bug Fixes
---------
Fix problems with pg_dump for inheritance, sequences, archive tables(Bruce)
Fix compile errors on overflow due to shifts, unsigned, and bad prototypes
        from Solaris(Diab Jerius)
Fix bugs in geometric line arithmetic (bad intersection calculations)(Thomas)
Check for geometric intersections at endpoints to avoid rounding ugliness(Thomas)
Catch non-functional delete attempts(Vadim)
Change time function names to be more consistent(Michael Reifenberg)
Check for zero divides(Michael Reifenberg)
Fix very old bug which made rows changed/inserted by a command
       visible to the command itself (so we had multiple update of
       updated rows, etc.)(Vadim)
Fix for SELECT null, 'fail' FROM pg_am (Patrick)
SELECT NULL as EMPTY_FIELD now allowed(Patrick)
Remove un-needed signal stuff from contrib/pginterface
Fix OR (where x != 1 or x isnull didn't return rows with x NULL) (Vadim)
Fix time_cmp function (Vadim)
Fix handling of functions with non-attribute first argument in
       WHERE clauses (Vadim)
Fix GROUP BY when order of entries is different from order
       in target list (Vadim)
Fix pg_dump for aggregates without sfunc1 (Vadim)

Enhancements
------------
Default genetic optimizer GEQO parameter is now 8(Bruce)
Allow use parameters in target list having aggregates in functions(Vadim)
Added JDBC driver as an interface(Adrian &amp; Peter)
pg_password utility
Return number of rows inserted/affected by INSERT/UPDATE/DELETE etc.(Vadim)
Triggers implemented with CREATE TRIGGER (SQL3)(Vadim)
SPI (Server Programming Interface) allows execution of queries inside
       C-functions (Vadim)
NOT NULL implemented (SQL92)(Robson Paniago de Miranda)
Include reserved words for string handling, outer joins, and unions(Thomas)
Implement extended comments ("/* ... */") using exclusive states(Thomas)
Add "//" single-line comments(Bruce)
Remove some restrictions on characters in operator names(Thomas)
DEFAULT and CONSTRAINT for tables implemented (SQL92)(Vadim &amp; Thomas)
Add text concatenation operator and function (SQL92)(Thomas)
Support WITH TIME ZONE syntax (SQL92)(Thomas)
Support INTERVAL unit TO unit syntax (SQL92)(Thomas)
Define types DOUBLE PRECISION, INTERVAL, CHARACTER,
       and CHARACTER VARYING (SQL92)(Thomas)
Define type FLOAT(p) and rudimentary DECIMAL(p,s), NUMERIC(p,s) (SQL92)(Thomas)
Define EXTRACT(), POSITION(), SUBSTRING(), and TRIM() (SQL92)(Thomas)
Define CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP (SQL92)(Thomas)
Add syntax and warnings for UNION, HAVING, INNER and OUTER JOIN (SQL92)(Thomas)
Add more reserved words, mostly for SQL92 compliance(Thomas)
Allow hh:mm:ss time entry for timespan/reltime types(Thomas)
Add center() routines for lseg, path, polygon(Thomas)
Add distance() routines for circle-polygon, polygon-polygon(Thomas)
Check explicitly for points and polygons contained within polygons
       using an axis-crossing algorithm(Thomas)
Add routine to convert circle-box(Thomas)
Merge conflicting operators for different geometric data types(Thomas)
Replace distance operator "&lt;===&gt;" with "&lt;-&gt;"(Thomas)
Replace "above" operator "!^" with "&gt;^" and "below" operator "!|" with "&lt;^"(Thomas)
Add routines for text trimming on both ends, substring, and string position(Thomas)
Added conversion routines circle(box) and poly(circle)(Thomas)
Allow internal sorts to be stored in memory rather than in files(Bruce &amp; Vadim)
Allow functions and operators on internally-identical types to succeed(Bruce)
Speed up backend start-up after profiling analysis(Bruce)
Inline frequently called functions for performance(Bruce)
Reduce open() calls(Bruce)
psql:  Add PAGER for \h and \?,\C fix
Fix for psql pager when no tty(Bruce)
New entab utility(Bruce)
General trigger functions for referential integrity (Vadim)
General trigger functions for time travel (Vadim)
General trigger functions for AUTOINCREMENT/IDENTITY feature (Vadim)
MOVE implementation (Vadim)

Source Tree Changes
-------------------
HP-UX 10 patches (Vladimir Turin)
Added SCO support, (Daniel Harris)
MkLinux patches (Tatsuo Ishii)
Change geometric box terminology from "length" to "width"(Thomas)
Deprecate temporary unstored slope fields in geometric code(Thomas)
Remove restart instructions from INSTALL(Bruce)
Look in /usr/ucb first for install(Bruce)
Fix c++ copy example code(Thomas)
Add -o to psql manual page(Bruce)
Prevent relname unallocated string length from being copied into database(Bruce)
Cleanup for NAMEDATALEN use(Bruce)
Fix pg_proc names over 15 chars in output(Bruce)
Add strNcpy() function(Bruce)
remove some (void) casts that are unnecessary(Bruce)
new interfaces directory(Marc)
Replace fopen() calls with calls to fd.c functions(Bruce)
Make functions static where possible(Bruce)
enclose unused functions in #ifdef NOT_USED(Bruce)
Remove call to difftime() in timestamp support to fix SunOS(Bruce &amp; Thomas)
Changes for Digital Unix
Portability fix for pg_dumpall(Bruce)
Rename pg_attribute.attnvals to attdispersion(Bruce)
"intro/unix" manual page now "pgintro"(Bruce)
"built-in" manual page now "pgbuiltin"(Bruce)
"drop" manual page now "drop_table"(Bruce)
Add "create_trigger", "drop_trigger" manual pages(Thomas)
Add constraints regression test(Vadim &amp; Thomas)
Add comments syntax regression test(Thomas)
Add PGINDENT and support program(Bruce)
Massive commit to run PGINDENT on all *.c and *.h files(Bruce)
Files moved to /src/tools directory(Bruce)
SPI and Trigger programming guides (Vadim &amp; D'Arcy)
</programlisting>
</para>
</sect2>
</sect1>

<sect1 id="release-6-1-1">
<title>Release 6.1.1</title>

  <note>
  <title>Release date</title>
  <simpara>1997-07-22</simpara>
  </note>

<sect2>
<title>Migration from version 6.1 to version 6.1.1</title>

<para>
This is a minor bug-fix release. A dump/reload is not required from version 6.1,
but is required from any release prior to 6.1.
Refer to the release notes for 6.1 for more details.
</para>
</sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
fix for SET with options (Thomas)
allow pg_dump/pg_dumpall to preserve ownership of all tables/objects(Bruce)
new psql \connect option allows changing usernames without changing databases
fix for initdb --debug option(Yoshihiko Ichikawa))
lextest cleanup(Bruce)
hash fixes(Vadim)
fix date/time month boundary arithmetic(Thomas)
fix timezone daylight handling for some ports(Thomas, Bruce, Tatsuo)
timestamp overhauled to use standard functions(Thomas)
other code cleanup in date/time routines(Thomas)
psql's \d now case-insensitive(Bruce)
psql's backslash commands can now have trailing semicolon(Bruce)
fix memory leak in psql when using \g(Bruce)
major fix for endian handling of communication to server(Thomas, Tatsuo)
Fix for Solaris assembler and include files(Yoshihiko Ichikawa)
allow underscores in usernames(Bruce)
pg_dumpall now returns proper status, portability fix(Bruce)
    </programlisting>
   </para>
  </sect2>
 </sect1>

<sect1 id="release-6-1">
<title>Release 6.1</title>

  <note>
  <title>Release date</title>
  <simpara>1997-06-08</simpara>
  </note>

<para>
 The regression tests have been adapted and extensively modified for the
 6.1 release of <productname>PostgreSQL</productname>.
</para>

<para>
 Three new data types (<type>datetime</type>, <type>timespan</type>, and <type>circle</type>) have been added to
 the native set of <productname>PostgreSQL</productname> types. Points, boxes, paths, and polygons
 have had their output formats made consistent across the data types.
 The polygon output in misc.out has only been spot-checked for correctness
 relative to the original regression output.
</para>

<para>
 <productname>PostgreSQL</productname> 6.1 introduces a new, alternate
optimizer which uses <firstterm>genetic</firstterm>
 algorithms. These algorithms introduce a random behavior in the ordering
 of query results when the query contains multiple qualifiers or multiple
 tables (giving the optimizer a choice on order of evaluation). Several
 regression tests have been modified to explicitly order the results, and
 hence are insensitive to optimizer choices. A few regression tests are
 for data types which are inherently unordered (e.g. points and time
 intervals) and tests involving those types are explicitly bracketed with
 <command>set geqo to 'off'</command> and <command>reset geqo</command>.
</para>

<para>
 The interpretation of array specifiers (the curly braces around atomic
 values) appears to have changed sometime after the original regression
 tests were generated. The current <filename>./expected/*.out</filename> files reflect this
 new interpretation, which might not be correct!
</para>

<para>
 The float8 regression test fails on at least some platforms. This is due
 to differences in implementations of <function>pow()</function> and <function>exp()</function> and the signaling
 mechanisms used for overflow and underflow conditions.
</para>

<para>
 The <quote>random</> results in the random test should cause the
 <quote>random</quote> test to be <quote>failed</quote>, since the
 regression tests are evaluated using a simple diff. However,
 <quote>random</> does not seem to produce random results on my test
 machine (Linux/<application>gcc</>/i686).
</para>

<sect2>
<title>Migration to Version 6.1</title>

<para>
This migration requires a complete dump of the 6.0 database and a
restore of the database in 6.1.
</para>
<para>
Those migrating from earlier 1.* releases should first upgrade to 1.09
because the COPY output format was improved from the 1.02 release.
</para>
</sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Bug Fixes
---------
packet length checking in library routines
lock manager priority patch
check for under/over flow of float8(Bruce)
multitable join fix(Vadim)
SIGPIPE crash fix(Darren)
large object fixes(Sven)
allow btree indexes to handle NULLs(Vadim)
timezone fixes(D'Arcy)
select SUM(x) can return NULL on no rows(Thomas)
internal optimizer, executor bug fixes(Vadim)
fix problem where inner loop in &lt; or &lt;= has no rows(Vadim)
prevent re-commuting join index clauses(Vadim)
fix join clauses for multiple tables(Vadim)
fix hash, hashjoin for arrays(Vadim)
fix btree for abstime type(Vadim)
large object fixes(Raymond)
fix buffer leak in hash indexes (Vadim)
fix rtree for use in inner scan (Vadim)
fix gist for use in inner scan, cleanups (Vadim, Andrea)
avoid unnecessary local buffers allocation (Vadim, Massimo)
fix local buffers leak in transaction aborts (Vadim)
fix file manager memmory leaks, cleanups (Vadim, Massimo)
fix storage manager memmory leaks (Vadim)
fix btree duplicates handling (Vadim)
fix deleted rows reincarnation caused by vacuum (Vadim)
fix SELECT varchar()/char() INTO TABLE made zero-length fields(Bruce)
many psql, pg_dump, and libpq memory leaks fixed using Purify (Igor)

Enhancements
------------
attribute optimization statistics(Bruce)
much faster new btree bulk load code(Paul)
BTREE UNIQUE added to bulk load code(Vadim)
new lock debug code(Massimo)
massive changes to libpg++(Leo)
new GEQO optimizer speeds table multitable optimization(Martin)
new WARN message for non-unique insert into unique key(Marc)
update x=-3, no spaces, now valid(Bruce)
remove case-sensitive identifier handling(Bruce,Thomas,Dan)
debug backend now pretty-prints tree(Darren)
new Oracle character functions(Edmund)
new plaintext password functions(Dan)
no such class or insufficient privilege changed to distinct messages(Dan)
new ANSI timestamp function(Dan)
new ANSI Time and Date types (Thomas)
move large chunks of data in backend(Martin)
multicolumn btree indexes(Vadim)
new SET var TO value command(Martin)
update transaction status on reads(Dan)
new locale settings for character types(Oleg)
new SEQUENCE serial number generator(Vadim)
GROUP BY function now possible(Vadim)
re-organize regression test(Thomas,Marc)
new optimizer operation weights(Vadim)
new psql \z grant/permit option(Marc)
new MONEY data type(D'Arcy,Thomas)
tcp socket communication speed improved(Vadim)
new VACUUM option for attribute statistics, and for certain columns (Vadim)
many geometric type improvements(Thomas,Keith)
additional regression tests(Thomas)
new datestyle variable(Thomas,Vadim,Martin)
more comparison operators for sorting types(Thomas)
new conversion functions(Thomas)
new more compact btree format(Vadim)
allow pg_dumpall to preserve database ownership(Bruce)
new SET GEQO=# and R_PLANS variable(Vadim)
old (!GEQO) optimizer can use right-sided plans (Vadim)
typechecking improvement in SQL parser(Bruce)
new SET, SHOW, RESET commands(Thomas,Vadim)
new \connect database USER option
new destroydb -i option (Igor)
new \dt and \di psql commands (Darren)
SELECT "\n" now escapes newline (A. Duursma)
new geometry conversion functions from old format (Thomas)

Source tree changes
-------------------
new configuration script(Marc)
readline configuration option added(Marc)
OS-specific configuration options removed(Marc)
new OS-specific template files(Marc)
no more need to edit Makefile.global(Marc)
re-arrange include files(Marc)
nextstep patches (Gregor Hoffleit)
removed Windows-specific code(Bruce)
removed postmaster -e option, now only postgres -e option (Bruce)
merge duplicate library code in front/backends(Martin)
now works with eBones, international Kerberos(Jun)
more shared library support
c++ include file cleanup(Bruce)
warn about buggy flex(Bruce)
DG/UX, Ultrix, IRIX, AIX portability fixes
</programlisting>
</para>
</sect2>
</sect1>

<sect1 id="release-6-0">
<title>Release 6.0</title>

  <note>
  <title>Release date</title>
  <simpara>1997-01-29</simpara>
  </note>

<para>
A dump/restore is required for those wishing to migrate data from
previous releases of <productname>PostgreSQL</productname>.
</para>

<sect2>
<title>Migration from version 1.09 to version 6.0</title>

<para>
This migration requires a complete dump of the 1.09 database and a
restore of the database in 6.0.
</para>
</sect2>

<sect2>
<title>Migration from pre-1.09 to version 6.0</title>

<para>
Those migrating from earlier 1.* releases should first upgrade to 1.09
because the COPY output format was improved from the 1.02 release.
</para>
</sect2>

  <sect2>
   <title>Changes</title>

   <para>
    <programlisting>
Bug Fixes
---------
ALTER TABLE bug - running postgres process needs to re-read table definition
Allow vacuum to be run on one table or entire database(Bruce)
Array fixes
Fix array over-runs of memory writes(Kurt)
Fix elusive btree range/non-range bug(Dan)
Fix for hash indexes on some types like time and date
Fix for pg_log size explosion
Fix permissions on lo_export()(Bruce)
Fix uninitialized reads of memory(Kurt)
Fixed ALTER TABLE ... char(3) bug(Bruce)
Fixed a few small memory leaks
Fixed EXPLAIN handling of options and changed full_path option name
Fixed output of group acl privileges
Memory leaks (hunt and destroy with tools like Purify(Kurt)
Minor improvements to rules system
NOTIFY fixes
New asserts for run-checking
Overhauled parser/analyze code to properly report errors and increase speed
Pg_dump -d now handles NULL's properly(Bruce)
Prevent SELECT NULL from crashing server (Bruce)
Properly report errors when INSERT ... SELECT columns did not match
Properly report errors when insert column names were not correct
psql \g filename now works(Bruce)
psql fixed problem with multiple statements on one line with multiple outputs
Removed duplicate system OIDs
SELECT * INTO TABLE . GROUP/ORDER BY gives unlink error if table exists(Bruce)
Several fixes for queries that crashed the backend
Starting quote in insert string errors(Bruce)
Submitting an empty query now returns empty status, not just " " query(Bruce)

Enhancements
------------
Add EXPLAIN manual page(Bruce)
Add UNIQUE index capability(Dan)
Add hostname/user level access control rather than just hostname and user
Add synonym of != for &lt;&gt;(Bruce)
Allow "select oid,* from table"
Allow BY,ORDER BY to specify columns by number, or by non-alias table.column(Bruce)
Allow COPY from the frontend(Bryan)
Allow GROUP BY to use alias column name(Bruce)
Allow actual compression, not just reuse on the same page(Vadim)
Allow installation-configuration option to auto-add all local users(Bryan)
Allow libpq to distinguish between text value '' and null(Bruce)
Allow non-postgres users with createdb privs to destroydb's
Allow restriction on who can create C functions(Bryan)
Allow restriction on who can do backend COPY(Bryan)
Can shrink tables, pg_time and pg_log(Vadim &amp; Erich)
Change debug level 2 to print queries only, changed debug heading layout(Bruce)
Change default decimal constant representation from float4 to float8(Bruce)
European date format now set when postmaster is started
Execute lowercase function names if not found with exact case
Fixes for aggregate/GROUP processing, allow 'select sum(func(x),sum(x+y) from z'
Gist now included in the distribution(Marc)
Idend authentication of local users(Bryan)
Implement BETWEEN qualifier(Bruce)
Implement IN qualifier(Bruce)
libpq has PQgetisnull()(Bruce)
libpq++ improvements
New options to initdb(Bryan)
Pg_dump allow dump of OIDs(Bruce)
Pg_dump create indexes after tables are loaded for speed(Bruce)
Pg_dumpall dumps all databases, and the user table
Pginterface additions for NULL values(Bruce)
Prevent postmaster from being run as root
psql \h and \? is now readable(Bruce)
psql allow backslashed, semicolons anywhere on the line(Bruce)
psql changed command prompt for lines in query or in quotes(Bruce)
psql char(3) now displays as (bp)char in \d output(Bruce)
psql return code now more accurate(Bryan?)
psql updated help syntax(Bruce)
Re-visit and fix vacuum(Vadim)
Reduce size of regression diffs, remove timezone name difference(Bruce)
Remove compile-time parameters to enable binary distributions(Bryan)
Reverse meaning of HBA masks(Bryan)
Secure Authentication of local users(Bryan)
Speed up vacuum(Vadim)
Vacuum now had VERBOSE option(Bruce)

Source tree changes
-------------------
All functions now have prototypes that are compared against the calls
Allow asserts to be disabled easily from Makefile.global(Bruce)
Change oid constants used in code to #define names
Decoupled sparc and solaris defines(Kurt)
Gcc -Wall compiles cleanly with warnings only from unfixable constructs
Major include file reorganization/reduction(Marc)
Make now stops on compile failure(Bryan)
Makefile restructuring(Bryan, Marc)
Merge bsdi_2_1 to bsdi(Bruce)
Monitor program removed
Name change from Postgres95 to PostgreSQL
New config.h file(Marc, Bryan)
PG_VERSION now set to 6.0 and used by postmaster
Portability additions, including Ultrix, DG/UX, AIX, and Solaris
Reduced the number of #define's, centralized #define's
Remove duplicate OIDS in system tables(Dan)
Remove duplicate system catalog info or report mismatches(Dan)
Removed many os-specific #define's
Restructured object file generation/location(Bryan, Marc)
Restructured port-specific file locations(Bryan, Marc)
Unused/uninitialized variables corrected
</programlisting>
</para>
</sect2>
</sect1>

<sect1 id="release-1-09">
<title>Release 1.09</title>

  <note>
  <title>Release date</title>
  <simpara>1996-11-04</simpara>
  </note>

<para>
Sorry, we didn't keep track of changes from 1.02 to 1.09.  Some of
the changes listed in 6.0 were actually included in the 1.02.1 to 1.09
releases.
</para>
</sect1>

<sect1 id="release-1-02">
<title>Release 1.02</title>

  <note>
  <title>Release date</title>
  <simpara>1996-08-01</simpara>
  </note>

<sect2>
<title>Migration from version 1.02 to version 1.02.1</title>

<para>
Here is a new migration file for 1.02.1.  It includes the 'copy' change
and a script to convert old <acronym>ASCII</acronym> files.
</para>
<note>
<para>
The following notes are for the benefit of users who want to migrate
databases from <productname>Postgres95</> 1.01 and 1.02 to <productname>Postgres95</> 1.02.1.
</para>
<para>
If you are starting afresh with <productname>Postgres95</> 1.02.1 and do not need
to migrate old databases, you do not need to read any further.
</para>
</note>

<para>
In order to upgrade older <productname>Postgres95</> version 1.01 or 1.02 databases to
version 1.02.1, the following steps are required:
</para>
<procedure>
<step>
<para>
Start up a new 1.02.1 postmaster
</para>
</step>
<step>
<para>
Add the new built-in functions and operators of 1.02.1 to 1.01 or 1.02
  databases.  This is done by running the new 1.02.1 server against
  your own 1.01 or 1.02 database and applying the queries attached at
  the end of the file.   This can be done easily through <command>psql</>.  If your
  1.01 or 1.02 database is named <literal>testdb</literal> and you have cut the commands
  from the end of this file and saved them in <filename>addfunc.sql</filename>:
<programlisting>
       % psql testdb -f addfunc.sql
</programlisting>

Those upgrading 1.02 databases will get a warning when executing the
last two statements in the file because they are already present in 1.02.  This is
not a cause for concern.
</para>
</step>
</procedure>
</sect2>

<sect2>
<title>Dump/Reload Procedure</title>

<para>
If you are trying to reload a pg_dump or text-mode, <literal>copy tablename to
stdout</literal> generated with a previous version, you will need to run the
attached <command>sed</command> script on the ASCII file before loading it into the
database.  The old format used '.' as end-of-data, while '\.' is now the
end-of-data marker.  Also, empty strings are now loaded in as '' rather
than NULL. See the copy manual page for full details.

<programlisting>
       sed 's/^\.$/\\./g' &lt;in_file &gt;out_file
</programlisting>
</para>
<para>
If you are loading an older binary copy or non-<systemitem>stdout</> copy, there is no
end-of-data character, and hence no conversion necessary.

<programlisting>
-- following lines added by agc to reflect the case-insensitive
-- regexp searching for varchar (in 1.02), and bpchar (in 1.02.1)
create operator ~* (leftarg = bpchar, rightarg = text, procedure = texticregexeq);
create operator !~* (leftarg = bpchar, rightarg = text, procedure = texticregexne);
create operator ~* (leftarg = varchar, rightarg = text, procedure = texticregexeq);
create operator !~* (leftarg = varchar, rightarg = text, procedure = texticregexne);
</programlisting>
</para>
</sect2>

<sect2>
<title>Changes</title>

<para>
<programlisting>
Source code maintenance and development
 * worldwide team of volunteers
 * the source tree now in CVS at ftp.ki.net

Enhancements
 * psql (and underlying libpq library) now has many more options for
   formatting output, including HTML
 * pg_dump now output the schema and/or the data, with many fixes to
   enhance completeness.
 * psql used in place of monitor in administration shell scripts.
   monitor to be deprecated in next release.
 * date/time functions enhanced
 * NULL insert/update/comparison fixed/enhanced
 * TCL/TK lib and shell fixed to work with both tck7.4/tk4.0 and tcl7.5/tk4.1

Bug Fixes (almost too numerous to mention)
 * indexes
 * storage management
 * check for NULL pointer before dereferencing
 * Makefile fixes

New Ports
 * added SolarisX86 port
 * added BSD/OS 2.1 port
 * added DG/UX port
</programlisting>
</para>
<!--
Contributors (apologies to any missed)
 * Kurt J. Lidl &lt;lidl@va.pubnix.com&gt;
        (missed in first run, but no less important)
 * Erich Stamberger &lt;eberger@gewi.kfunigraz.ac.at&gt;
 * Jason Wright &lt;jason@shiloh.vnet.net&gt;
 * Cees de Groot &lt;C.deGroot@inter.NL.net&gt;
 * ernst.molitor@uni-bonn.de
 * michael.siebenborn@ae3.Hypo.DE (Michael Siebenborn (6929))
 * Brian E. Gallew &lt;geek+@cmu.edu&gt;
 * Vadim B. Mikheev &lt;vadim@sable.krasnoyarsk.su&gt;
 * Adam Sussman &lt;myddryn@vidya.com&gt;
 * Chris Dunlop &lt;chris@onthe.net.au&gt;
 * Marc G. Fournier &lt;scrappy@ki.net&gt;
 * Dan McGuirk &lt;mcguirk@indirect.com&gt;
 * Dr_George_D_Detlefsen &lt;drgeorge@ilt.com&gt;
 * Erich Stamberger &lt;eberger@gewi.kfunigraz.ac.at&gt;
 * Massimo Dal Zotto &lt;dz@cs.unitn.it&gt;
 * Randy Kunkee &lt;kunkee@Starbase.NeoSoft.COM&gt;
 * Rick Weldon &lt;rick@wisetech.com&gt;
 * Thomas van Reimersdahl &lt;reimersd@dali.techinfo.rwth-aachen.de&gt;
 * david bennett &lt;dave@bensoft.com&gt;
 * ernst.molitor@uni-bonn.de
 * Julian Assange &lt;proff@suburbia.net&gt;
 * Bruce Momjian &lt;pgman@candle.pha.pa.us&gt;
 * Paul "Shag" Walmsley &lt;ccshag@cclabs.missouri.edu&gt;
 * "Alistair G. Crooks" &lt;azcb0@sde.uts.amdahl.com&gt;
-->
</sect2>
</sect1>

<sect1 id="release-1-01">
<title>Release 1.01</title>

   <note>
   <title>Release date</title>
   <simpara>1996-02-23</simpara>
   </note>


<sect2>
<title>Migration from version 1.0 to version 1.01</title>

<para>
The following notes are for the benefit of users who want to migrate
databases from <productname>Postgres95</> 1.0 to <productname>Postgres95</> 1.01.
</para>
<para>
If you are starting afresh with <productname>Postgres95</> 1.01 and do not need
to migrate old databases, you do not need to read any further.
</para>
<para>
In order to <productname>Postgres95</> version 1.01 with databases created with
<productname>Postgres95</> version 1.0, the following steps are required:
</para>
<procedure>
<step>
<para>
Set the definition of <symbol>NAMEDATALEN</symbol> in <filename>src/Makefile.global</filename> to 16
   and <symbol>OIDNAMELEN</symbol> to 20.
</para>
</step>
<step>
<para>
Decide whether you want to use Host based authentication.
</para>
<substeps>
<step>
<para>
If you do, you must create a file name <literal>pg_hba</literal> in your top-level data
   directory (typically the value of your <envar>$PGDATA</envar>).  <filename>src/libpq/pg_hba</filename>
   shows an example syntax.
</para>
</step>
<step>
<para>
If you do not want host-based authentication, you can comment out
   the line:
<programlisting>
        HBA = 1
</programlisting>
   in <filename>src/Makefile.global</filename>
</para>
<para>
   Note that host-based authentication is turned on by default, and if
   you do not take steps A or B above, the out-of-the-box 1.01 will
   not allow you to connect to 1.0 databases.
</para>
</step>
</substeps>
</step>

<step>
<para>
Compile and install 1.01, but DO NOT do the <command>initdb</command> step.
</para>
</step>
<step>
<para>
Before doing anything else, terminate your 1.0 postmaster, and
   backup your existing <envar>$PGDATA</envar> directory.
</para>
</step>
<step>
<para>
Set your <envar>PGDATA</envar> environment variable to your 1.0 databases, but set up
   path up so that 1.01 binaries are being used.
</para>
</step>
<step>
<para>
Modify the file <filename><envar>$PGDATA</envar>/PG_VERSION</filename> from 5.0 to 5.1
</para>
</step>
<step>
<para>
Start up a new 1.01 postmaster
</para>
</step>
<step>
<para>
Add the new built-in functions and operators of 1.01 to 1.0
   databases.  This is done by running the new 1.01 server against
   your own 1.0 database and applying the queries attached and saving
   in the file 1.0_to_1.01.sql.   This can be done easily through <command>psql</command>.
   If your 1.0 database is name <literal>testdb</literal>:

<programlisting>
        % psql testdb -f 1.0_to_1.01.sql
</programlisting>

and then execute the following commands (cut and paste from here):

<programlisting>
-- add builtin functions that are new to 1.01

create function int4eqoid (int4, oid) returns bool as 'foo'
language 'internal';
create function oideqint4 (oid, int4) returns bool as 'foo'
language 'internal';
create function char2icregexeq (char2, text) returns bool as 'foo'
language 'internal';
create function char2icregexne (char2, text) returns bool as 'foo'
language 'internal';
create function char4icregexeq (char4, text) returns bool as 'foo'
language 'internal';
create function char4icregexne (char4, text) returns bool as 'foo'
language 'internal';
create function char8icregexeq (char8, text) returns bool as 'foo'
language 'internal';
create function char8icregexne (char8, text) returns bool as 'foo'
language 'internal';
create function char16icregexeq (char16, text) returns bool as 'foo'
language 'internal';
create function char16icregexne (char16, text) returns bool as 'foo'
language 'internal';
create function texticregexeq (text, text) returns bool as 'foo'
language 'internal';
create function texticregexne (text, text) returns bool as 'foo'
language 'internal';

-- add builtin functions that are new to 1.01

create operator = (leftarg = int4, rightarg = oid, procedure = int4eqoid);
create operator = (leftarg = oid, rightarg = int4, procedure = oideqint4);
create operator ~* (leftarg = char2, rightarg = text, procedure = char2icregexeq);
create operator !~* (leftarg = char2, rightarg = text, procedure = char2icregexne);
create operator ~* (leftarg = char4, rightarg = text, procedure = char4icregexeq);
create operator !~* (leftarg = char4, rightarg = text, procedure = char4icregexne);
create operator ~* (leftarg = char8, rightarg = text, procedure = char8icregexeq);
create operator !~* (leftarg = char8, rightarg = text, procedure = char8icregexne);
create operator ~* (leftarg = char16, rightarg = text, procedure = char16icregexeq);
create operator !~* (leftarg = char16, rightarg = text, procedure = char16icregexne);
create operator ~* (leftarg = text, rightarg = text, procedure = texticregexeq);
create operator !~* (leftarg = text, rightarg = text, procedure = texticregexne);
</programlisting>
</para>
</step>
</procedure>
</sect2>

<sect2>
<title>Changes</title>

<para>
<programlisting>
Incompatibilities:
 * 1.01 is backwards compatible with 1.0 database provided the user
   follow the steps outlined in the MIGRATION_from_1.0_to_1.01 file.
   If those steps are not taken, 1.01 is not compatible with 1.0 database.

Enhancements:
 * added PQdisplayTuples() to libpq and changed monitor and psql to use it
 * added NeXT port (requires SysVIPC implementation)
 * added CAST .. AS ... syntax
 * added ASC and DESC key words
 * added 'internal' as a possible language for CREATE FUNCTION
   internal functions are C functions which have been statically linked
   into the postgres backend.
 * a new type "name" has been added for system identifiers (table names,
   attribute names, etc.)  This replaces the old char16 type.   The
   of name is set by the NAMEDATALEN #define in src/Makefile.global
 * a readable reference manual that describes the query language.
 * added host-based access control.  A configuration file ($PGDATA/pg_hba)
   is used to hold the configuration data.  If host-based access control
   is not desired, comment out HBA=1 in src/Makefile.global.
 * changed regex handling to be uniform use of Henry Spencer's regex code
   regardless of platform.  The regex code is included in the distribution
 * added functions and operators for case-insensitive regular expressions.
   The operators are ~* and !~*.
 * pg_dump uses COPY instead of SELECT loop for better performance

Bug fixes:
 * fixed an optimizer bug that was causing core dumps when
   functions calls were used in comparisons in the WHERE clause
 * changed all uses of getuid to geteuid so that effective uids are used
 * psql now returns non-zero status on errors when using -c
 * applied public patches 1-14
</programlisting>
</para>
</sect2>
</sect1>

<sect1 id="release-1-0">
<title>Release 1.0</title>

   <note>
   <title>Release date</title>
   <simpara>1995-09-05</simpara>
   </note>

<sect2>
<title>Changes</title>

<para>
<programlisting>
Copyright change:
 * The copyright of <productname>Postgres</productname> 1.0 has been loosened to be freely modifiable
   and modifiable for any purpose.  Please read the COPYRIGHT file.
   Thanks to Professor Michael Stonebraker for making this possible.

Incompatibilities:
 *  date formats have to be MM-DD-YYYY (or DD-MM-YYYY if you're using
   EUROPEAN STYLE).  This follows SQL-92 specs.
 *  "delimiters" is now a key word

Enhancements:
 *  sql LIKE syntax has been added
 *  copy command now takes an optional USING DELIMITER specification.
   delimiters can be any single-character string.
 *  IRIX 5.3 port has been added.
   Thanks to Paul Walmsley and others.
 *  updated pg_dump to work with new libpq
 *  \d has been added psql
   Thanks to Keith Parks
 *  regexp performance for architectures that use POSIX regex has been
   improved due to caching of precompiled patterns.
   Thanks to Alistair Crooks
 *  a new version of libpq++
   Thanks to William Wanders

Bug fixes:
 *  arbitrary userids can be specified in the createuser script
 *  \c to connect to other databases in psql now works.
 *  bad pg_proc entry for float4inc() is fixed
 *  users with usecreatedb field set can now create databases without
   having to be usesuper
 *  remove access control entries when the entry no longer has any
   privileges
 *  fixed non-portable datetimes implementation
 *  added kerberos flags to the src/backend/Makefile
 *  libpq now works with kerberos
 *  typographic errors in the user manual have been corrected.
 *  btrees with multiple index never worked, now we tell you they don't
   work when you try to use them
</programlisting>
</para>
</sect2>
</sect1>

<sect1 id="release-0-03">
<title><productname>Postgres95</productname> Release 0.03</title>

   <note>
   <title>Release date</title>
   <simpara>1995-07-21</simpara>
   </note>

<sect2>
<title>Changes</title>
<para>
<programlisting>
Incompatible changes:
 * BETA-0.3 IS INCOMPATIBLE WITH DATABASES CREATED WITH PREVIOUS VERSIONS
   (due to system catalog changes and indexing structure changes).
 * double-quote (") is deprecated as a quoting character for string literals;
   you need to convert them to single quotes ('). <!-- " -->
 * name of aggregates (eg. int4sum) are renamed in accordance with the
   SQL standard (eg. sum).
 * CHANGE ACL syntax is replaced by GRANT/REVOKE syntax.
 * float literals (eg. 3.14) are now of type float4 (instead of float8 in
   previous releases); you might have to do typecasting if you depend on it
   being of type float8.  If you neglect to do the typecasting and you assign
   a float literal to a field of type float8, you might get incorrect values
   stored!
 * LIBPQ has been totally revamped so that frontend applications
   can connect to multiple backends
 * the usesysid field in pg_user has been changed from int2 to int4 to
   allow wider range of Unix user ids.
 * the netbsd/freebsd/bsd o/s ports have been consolidated into a
   single BSD44_derived port.  (thanks to Alistair Crooks)

SQL standard-compliance (the following details changes that makes postgres95
more compliant to the SQL-92 standard):
 * the following SQL types are now built-in: smallint, int(eger), float, real,
   char(N), varchar(N), date and time.

   The following are aliases to existing postgres types:
                smallint -&gt; int2
                integer, int -&gt; int4
                float, real  -&gt; float4
   char(N) and varchar(N) are implemented as truncated text types. In
   addition, char(N) does blank-padding.
 * single-quote (') is used for quoting string literals; '' (in addition to
   \') is supported as means of inserting a single quote in a string
 * SQL standard aggregate names (MAX, MIN, AVG, SUM, COUNT) are used
   (Also, aggregates can now be overloaded, i.e. you can define your
   own MAX aggregate to take in a user-defined type.)
 * CHANGE ACL removed. GRANT/REVOKE syntax added.
   - Privileges can be given to a group using the "GROUP" key word.
        For example:
                GRANT SELECT ON foobar TO GROUP my_group;
        The key word 'PUBLIC' is also supported to mean all users.

        Privileges can only be granted or revoked to one user or group
        at a time.

        "WITH GRANT OPTION" is not supported.  Only class owners can change
        access control
   - The default access control is to grant users readonly access.
     You must explicitly grant insert/update access to users.  To change
     this, modify the line in
                src/backend/utils/acl.h
     that defines ACL_WORLD_DEFAULT

Bug fixes:
 * the bug where aggregates of empty tables were not run has been fixed. Now,
   aggregates run on empty tables will return the initial conditions of the
   aggregates. Thus, COUNT of an empty  table will now properly return 0.
   MAX/MIN of an empty table will return a row of value NULL.
 * allow the use of \; inside the monitor
 * the LISTEN/NOTIFY asynchronous notification mechanism now work
 * NOTIFY in rule action bodies now work
 * hash indexes work, and access methods in general should perform better.
   creation of large btree indexes should be much faster.  (thanks to Paul
   Aoki)

Other changes and enhancements:
 * addition of an EXPLAIN statement used for explaining the query execution
   plan (eg. "EXPLAIN SELECT * FROM EMP" prints out the execution plan for
   the query).
 * WARN and NOTICE messages no longer have timestamps on them. To turn on
   timestamps of error messages, uncomment the line in
   src/backend/utils/elog.h:
        /* define ELOG_TIMESTAMPS */
 * On an access control violation, the message
        "Either no such class or insufficient privilege"
   will be given.  This is the same message that is returned when
   a class is not found.  This dissuades non-privileged users from
   guessing the existence of privileged classes.
 * some additional system catalog changes have been made that are not
   visible to the user.

libpgtcl changes:
 * The -oid option has been added to the "pg_result" tcl command.
   pg_result -oid returns oid of the last row inserted.   If the
   last command was not an INSERT, then pg_result -oid returns "".
 * the large object interface is available as pg_lo* tcl commands:
   pg_lo_open, pg_lo_close, pg_lo_creat, etc.

Portability enhancements and New Ports:
 * flex/lex problems have been cleared up.  Now, you should be able to use
   flex instead of lex on any platforms.  We no longer make assumptions of
   what lexer you use based on the platform you use.
 * The Linux-ELF port is now supported.  Various configuration have been
   tested:  The following configuration is known to work:
        kernel 1.2.10, gcc 2.6.3, libc 4.7.2, flex 2.5.2, bison 1.24
   with everything in ELF format,

New utilities:
 * ipcclean added to the distribution
   ipcclean usually does not need to be run, but if your backend crashes
   and leaves shared memory segments hanging around, ipcclean will
   clean them up for you.

New documentation:
 * the user manual has been revised and libpq documentation added.
</programlisting>
</para>
</sect2>
</sect1>

<sect1 id="release-0-02">
<title><productname>Postgres95</productname> Release 0.02</title>

   <note>
   <title>Release date</title>
   <simpara>1995-05-25</simpara>
   </note>

<sect2>
<title>Changes</title>

<para>
<programlisting>
Incompatible changes:
 * The SQL statement for creating a database is 'CREATE DATABASE' instead
   of 'CREATEDB'. Similarly, dropping a database is 'DROP DATABASE' instead
   of 'DESTROYDB'. However, the names of the executables 'createdb' and
   'destroydb' remain the same.

New tools:
 * pgperl - a Perl (4.036) interface to Postgres95
 * pg_dump - a utility for dumping out a postgres database into a
        script file containing query commands. The script files are in a ASCII
        format and can be used to reconstruct the database, even on other
        machines and other architectures. (Also good for converting
        a Postgres 4.2 database to Postgres95 database.)

The following ports have been incorporated into postgres95-beta-0.02:
 * the NetBSD port by Alistair Crooks
 * the AIX port by Mike Tung
 * the Windows NT port by Jon Forrest (more stuff but not done yet)
 * the Linux ELF port by Brian Gallew

The following bugs have been fixed in postgres95-beta-0.02:
 * new lines not escaped in COPY OUT and problem with COPY OUT when first
   attribute is a '.'
 * cannot type return to use the default user id in createuser
 * SELECT DISTINCT on big tables crashes
 * Linux installation problems
 * monitor doesn't allow use of 'localhost' as PGHOST
 * psql core dumps when doing \c or \l
 * the "pgtclsh" target missing from src/bin/pgtclsh/Makefile
 * libpgtcl has a hard-wired default port number
 * SELECT DISTINCT INTO TABLE hangs
 * CREATE TYPE doesn't accept 'variable' as the internallength
 * wrong result using more than 1 aggregate in a SELECT
</programlisting>
</para>
</sect2>
</sect1>

<sect1 id="release-0-01">
<title><productname>Postgres95</productname> Release 0.01</title>

   <note>
   <title>Release date</title>
   <simpara>1995-05-01</simpara>
   </note>

<para>
Initial release.
</para>
</sect1>

<![IGNORE[
  <sect1 id="timing-results">
   <title>Timing Results</title>

   <para>
    These timing results are from running the regression test with the commands

    <programlisting>
% cd src/test/regress
% make all
% time make runtest
    </programlisting>
   </para>
   <para>
    Timing under Linux 2.0.27 seems to have a roughly 5% variation from run
    to run, presumably due to the scheduling vagaries of multitasking systems.
   </para>

   <sect2>
    <title>Version 6.5</title>

    <para>
     As has been the case for previous releases, timing between
     releases is not directly comparable since new regression tests
     have been added. In general, 6.5 is faster than previous
     releases.
    </para>

    <para>
     Timing with <function>fsync()</function> disabled:

     <programlisting>
  Time   System
  02:00  Dual Pentium Pro 180, 224MB, UW-SCSI, Linux 2.0.36, gcc 2.7.2.3 -O2 -m486
  04:38  Sparc Ultra 1 143MHz, 64MB, Solaris 2.6
     </programlisting>
    </para>

    <para>
     Timing with <function>fsync()</function> enabled:

     <programlisting>
  Time   System
  04:21  Dual Pentium Pro 180, 224MB, UW-SCSI, Linux 2.0.36, gcc 2.7.2.3 -O2 -m486
     </programlisting>

     For the <systemitem class="osname">Linux</systemitem> system above, using <acronym>UW-SCSI</acronym> disks rather than (older) <acronym>IDE</acronym>
     disks leads to a 50% improvement in speed on the regression test.
    </para>
   </sect2>

<sect2>
<title>Version 6.4beta</title>

<para>
The times for this release are not directly comparable to those for previous releases
since some additional regression tests have been included.
In general, however, 6.4 should be slightly faster than the previous release (thanks, Bruce!).
</para>
<para>
<programlisting>
  Time   System
  02:26  Dual Pentium Pro 180, 96MB, UW-SCSI, Linux 2.0.30, gcc 2.7.2.1 -O2 -m486
</programlisting>
</para>
</sect2>

<sect2>
<title>Version 6.3</title>

<para>
The times for this release are not directly comparable to those for previous releases
since some additional regression tests have been included and some obsolete tests involving
time travel have been removed.
In general, however, 6.3 is substantially faster than previous releases (thanks, Bruce!).
</para>
<para>
<programlisting>
  Time   System
  02:30  Dual Pentium Pro 180, 96MB, UW-SCSI, Linux 2.0.30, gcc 2.7.2.1 -O2 -m486
  04:12  Dual Pentium Pro 180, 96MB, EIDE, Linux 2.0.30, gcc 2.7.2.1 -O2 -m486
</programlisting>
</para>
</sect2>

<sect2>
<title>Version 6.1</title>

<para>
<programlisting>
  Time   System
  06:12  Pentium Pro 180, 32MB, EIDE, Linux 2.0.30, gcc 2.7.2 -O2 -m486
  12:06  P-100, 48MB, Linux 2.0.29, gcc
  39:58  Sparc IPC 32MB, Solaris 2.5, gcc 2.7.2.1 -O -g
</programlisting>
</para>
</sect2>
</sect1>
]]>
</appendix>
