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 <sect1 id="release-8-3-7">
  <title>Release 8.3.7</title>

  <note>
  <title>Release date</title>
  <simpara>2009-03-16</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.3.6.
   For information about new features in the 8.3 major release, see
   <xref linkend="release-8-3">.
  </para>

  <sect2>
   <title>Migration to Version 8.3.7</title>

   <para>
    A dump/restore is not required for those running 8.3.X.
    However, if you are upgrading from a version earlier than 8.3.5,
    see the release notes for 8.3.5.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Prevent error recursion crashes when encoding conversion fails (Tom)
     </para>

     <para>
      This change extends fixes made in the last two minor releases for
      related failure scenarios.  The previous fixes were narrowly tailored
      for the original problem reports, but we have now recognized that
      <emphasis>any</> error thrown by an encoding conversion function could
      potentially lead to infinite recursion while trying to report the
      error.  The solution therefore is to disable translation and encoding
      conversion and report the plain-ASCII form of any error message,
      if we find we have gotten into a recursive error reporting situation.
      (CVE-2009-0922)
     </para>
    </listitem>

    <listitem>
     <para>
      Disallow <command>CREATE CONVERSION</> with the wrong encodings
      for the specified conversion function (Heikki)
     </para>

     <para>
      This prevents one possible scenario for encoding conversion failure.
      The previous change is a backstop to guard against other kinds of
      failures in the same area.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <function>xpath()</> to not modify the path expression unless
      necessary, and to make a saner attempt at it when necessary (Andrew)
     </para>

     <para>
      The SQL standard suggests that <function>xpath</> should work on data
      that is a document fragment, but <application>libxml</> doesn't support
      that, and indeed it's not clear that this is sensible according to the
      XPath standard.  <function>xpath</> attempted to work around this
      mismatch by modifying both the data and the path expression, but the
      modification was buggy and could cause valid searches to fail.  Now,
      <function>xpath</> checks whether the data is in fact a well-formed
      document, and if so invokes <application>libxml</> with no change to the
      data or path expression.  Otherwise, a different modification method
      that is somewhat less likely to fail is used.
     </para>

     <note>
      <para>
       The new modification method is still not 100% satisfactory, and it
       seems likely that no real solution is possible.  This patch should
       therefore be viewed as a band-aid to keep from breaking existing
       applications unnecessarily.  It is likely that
       <productname>PostgreSQL</> 8.4 will simply reject use of
       <function>xpath</> on data that is not a well-formed document.
      </para>
     </note>
    </listitem>

    <listitem>
     <para>
      Fix core dump when <function>to_char()</> is given format codes that
      are inappropriate for the type of the data argument (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible failure in text search when C locale is used with
      a multi-byte encoding (Teodor)
     </para>

     <para>
      Crashes were possible on platforms where <type>wchar_t</> is narrower
      than <type>int</>; Windows in particular.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix extreme inefficiency in text search parser's handling of an
      email-like string containing multiple <literal>@</> characters (Heikki)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix planner problem with sub-<command>SELECT</> in the output list
      of a larger subquery (Tom)
     </para>

     <para>
      The known symptom of this bug is a <quote>failed to locate grouping
      columns</> error that is dependent on the datatype involved;
      but there could be other issues as well.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix decompilation of <literal>CASE WHEN</> with an implicit coercion
      (Tom)
     </para>

     <para>
      This mistake could lead to Assert failures in an Assert-enabled build,
      or an <quote>unexpected CASE WHEN clause</> error message in other
      cases, when trying to examine or dump a view.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible misassignment of the owner of a TOAST table's rowtype (Tom)
     </para>

     <para>
      If <command>CLUSTER</> or a rewriting variant of <command>ALTER TABLE</>
      were executed by someone other than the table owner, the
      <structname>pg_type</> entry for the table's TOAST table would end up
      marked as owned by that someone.  This caused no immediate problems,
      since the permissions on the TOAST rowtype aren't examined by any
      ordinary database operation.  However, it could lead to unexpected
      failures if one later tried to drop the role that issued the command
      (in 8.1 or 8.2), or <quote>owner of data type appears to be invalid</>
      warnings from <application>pg_dump</> after having done so (in 8.3).
     </para>
    </listitem>

    <listitem>
     <para>
      Change <command>UNLISTEN</> to exit quickly if the current session has
      never executed any <command>LISTEN</> command (Tom)
     </para>

     <para>
      Most of the time this is not a particularly useful optimization, but
      since <command>DISCARD ALL</> invokes <command>UNLISTEN</>, the previous
      coding caused a substantial performance problem for applications that
      made heavy use of <command>DISCARD ALL</>.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix PL/pgSQL to not treat <literal>INTO</> after <command>INSERT</> as
      an INTO-variables clause anywhere in the string, not only at the start;
      in particular, don't fail for <command>INSERT INTO</> within
      <command>CREATE RULE</> (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Clean up PL/pgSQL error status variables fully at block exit
      (Ashesh Vashi and Dave Page)
     </para>

     <para>
      This is not a problem for PL/pgSQL itself, but the omission could cause
      the PL/pgSQL Debugger to crash while examining the state of a function.
     </para>
    </listitem>

    <listitem>
     <para>
      Retry failed calls to <function>CallNamedPipe()</> on Windows
      (Steve Marshall, Magnus)
     </para>

     <para>
      It appears that this function can sometimes fail transiently;
      we previously treated any failure as a hard error, which could
      confuse <command>LISTEN</>/<command>NOTIFY</> as well as other
      operations.
     </para>
    </listitem>

    <listitem>
     <para>
      Add <literal>MUST</> (Mauritius Island Summer Time) to the default list
      of known timezone abbreviations (Xavier Bugaud)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-3-6">
  <title>Release 8.3.6</title>

  <note>
  <title>Release date</title>
  <simpara>2009-02-02</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.3.5.
   For information about new features in the 8.3 major release, see
   <xref linkend="release-8-3">.
  </para>

  <sect2>
   <title>Migration to Version 8.3.6</title>

   <para>
    A dump/restore is not required for those running 8.3.X.
    However, if you are upgrading from a version earlier than 8.3.5,
    see the release notes for 8.3.5.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Make <command>DISCARD ALL</> release advisory locks, in addition
      to everything it already did (Tom)
     </para>

     <para>
      This was decided to be the most appropriate behavior.  This could
      affect existing applications, however.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix whole-index GiST scans to work correctly (Teodor)
     </para>

     <para>
      This error could cause rows to be lost if a table is clustered
      on a GiST index.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix crash of <literal>xmlconcat(NULL)</> (Peter)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible crash in <literal>ispell</> dictionary if high-bit-set
      characters are used as flags (Teodor)
     </para>

     <para>
      This is known to be done by one widely available Norwegian dictionary,
      and the same condition may exist in others.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix misordering of <application>pg_dump</> output for composite types
      (Tom)
     </para>

     <para>
      The most likely problem was for user-defined operator classes to
      be dumped after indexes or views that needed them.
     </para>
    </listitem>

    <listitem>
     <para>
      Improve handling of URLs in <function>headline()</> function (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Improve handling of overlength headlines in <function>headline()</>
      function (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Prevent possible Assert failure or misconversion if an encoding
      conversion is created with the wrong conversion function for the
      specified pair of encodings (Tom, Heikki)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible Assert failure if a statement executed in PL/pgSQL is
      rewritten into another kind of statement, for example if an
      <command>INSERT</> is rewritten into an <command>UPDATE</> (Heikki)
     </para>
    </listitem>

    <listitem>
     <para>
      Ensure that a snapshot is available to datatype input functions (Tom)
     </para>

     <para>
      This primarily affects domains that are declared with <literal>CHECK</>
      constraints involving user-defined stable or immutable functions.  Such
      functions typically fail if no snapshot has been set.
     </para>
    </listitem>

    <listitem>
     <para>
      Make it safer for SPI-using functions to be used within datatype I/O;
      in particular, to be used in domain check constraints (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Avoid unnecessary locking of small tables in <command>VACUUM</>
      (Heikki)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix a problem that sometimes kept <command>ALTER TABLE ENABLE/DISABLE
      RULE</> from being recognized by active sessions (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix a problem that made <literal>UPDATE RETURNING tableoid</>
      return zero instead of the correct OID (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Allow functions declared as taking <type>ANYARRAY</> to work on
      the <structname>pg_statistic</> columns of that type (Tom)
     </para>

     <para>
      This used to work, but was unintentionally broken in 8.3.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix planner misestimation of selectivity when transitive equality
      is applied to an outer-join clause (Tom)
     </para>

     <para>
      This could result in bad plans for queries like
      <literal>... from a left join b on a.a1 = b.b1 where a.a1 = 42 ...</>
     </para>
    </listitem>

    <listitem>
     <para>
      Improve optimizer's handling of long <literal>IN</> lists (Tom)
     </para>

     <para>
      This change avoids wasting large amounts of time on such lists
      when constraint exclusion is enabled.
     </para>
    </listitem>

    <listitem>
     <para>
      Prevent synchronous scan during GIN index build (Tom)
     </para>

     <para>
      Because GIN is optimized for inserting tuples in increasing TID order,
      choosing to use a synchronous scan could slow the build by a factor of
      three or more.
     </para>
    </listitem>

    <listitem>
     <para>
      Ensure that the contents of a holdable cursor don't depend on the
      contents of TOAST tables (Tom)
     </para>

     <para>
      Previously, large field values in a cursor result might be represented
      as TOAST pointers, which would fail if the referenced table got dropped
      before the cursor is read, or if the large value is deleted and then
      vacuumed away.  This cannot happen with an ordinary cursor,
      but it could with a cursor that is held past its creating transaction.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix memory leak when a set-returning function is terminated without
      reading its whole result (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix encoding conversion problems in XML functions when the database
      encoding isn't UTF-8 (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <filename>contrib/dblink</>'s
      <function>dblink_get_result(text,bool)</> function (Joe)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible garbage output from <filename>contrib/sslinfo</> functions
      (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix incorrect behavior of <filename>contrib/tsearch2</> compatibility
      trigger when it's fired more than once in a command (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible mis-signaling in autovacuum (Heikki)
     </para>
    </listitem>

    <listitem>
     <para>
      Support running as a service on Windows 7 beta (Dave and Magnus)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <application>ecpg</>'s handling of varchar structs (Michael)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <application>configure</> script to properly report failure when
      unable to obtain linkage information for PL/Perl (Andrew)
     </para>
    </listitem>

    <listitem>
     <para>
      Make all documentation reference <literal>pgsql-bugs</> and/or
      <literal>pgsql-hackers</> as appropriate, instead of the
      now-decommissioned <literal>pgsql-ports</> and <literal>pgsql-patches</>
      mailing lists (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Update time zone data files to <application>tzdata</> release 2009a (for
      Kathmandu and historical DST corrections in Switzerland, Cuba)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-3-5">
  <title>Release 8.3.5</title>

  <note>
  <title>Release date</title>
  <simpara>2008-11-03</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.3.4.
   For information about new features in the 8.3 major release, see
   <xref linkend="release-8-3">.
  </para>

  <sect2>
   <title>Migration to Version 8.3.5</title>

   <para>
    A dump/restore is not required for those running 8.3.X.
    However, if you are upgrading from a version earlier than 8.3.1,
    see the release notes for 8.3.1.  Also, if you were running a previous
    8.3.X release, it is recommended to <command>REINDEX</> all GiST
    indexes after the upgrade.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Fix GiST index corruption due to marking the wrong index entry
      <quote>dead</> after a deletion (Teodor)
     </para>

     <para>
      This would result in index searches failing to find rows they
      should have found.  Corrupted indexes can be fixed with
      <command>REINDEX</>.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix backend crash when the client encoding cannot represent a localized
      error message (Tom)
     </para>

     <para>
      We have addressed similar issues before, but it would still fail if
      the <quote>character has no equivalent</> message itself couldn't
      be converted.  The fix is to disable localization and send the plain
      ASCII error message when we detect such a situation.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible crash in <type>bytea</>-to-XML mapping (Michael McMaster)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible crash when deeply nested functions are invoked from
      a trigger (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Improve optimization of <replaceable>expression</> <literal>IN</>
      (<replaceable>expression-list</>) queries (Tom, per an idea from Robert
      Haas)
     </para>

     <para>
      Cases in which there are query variables on the right-hand side had been
      handled less efficiently in 8.2.x and 8.3.x than in prior versions.
      The fix restores 8.1 behavior for such cases.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix mis-expansion of rule queries when a sub-<literal>SELECT</> appears
      in a function call in <literal>FROM</>,  a multi-row <literal>VALUES</>
      list, or a <literal>RETURNING</> list (Tom)
     </para>

     <para>
      The usual symptom of this problem is an <quote>unrecognized node type</>
      error.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix Assert failure during rescan of an <literal>IS NULL</>
      search of a GiST index (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix memory leak during rescan of a hashed aggregation plan (Neil)
     </para>
    </listitem>

    <listitem>
     <para>
      Ensure an error is reported when a newly-defined PL/pgSQL trigger
      function is invoked as a normal function (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Force a checkpoint before <command>CREATE DATABASE</> starts to copy
      files (Heikki)
     </para>

     <para>
      This prevents a possible failure if files had recently been deleted
      in the source database.
     </para>
    </listitem>

    <listitem>
     <para>
      Prevent possible collision of <structfield>relfilenode</> numbers
      when moving a table to another tablespace with <command>ALTER SET
      TABLESPACE</> (Heikki)
     </para>

     <para>
      The command tried to re-use the existing filename, instead of
      picking one that is known unused in the destination directory.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix incorrect text search headline generation when single query
      item matches first word of text (Sushant Sinha)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix improper display of fractional seconds in interval values when
      using a non-ISO datestyle in an <option>--enable-integer-datetimes</>
      build (Ron Mayer)
     </para>
    </listitem>

    <listitem>
     <para>
      Make <literal>ILIKE</> compare characters case-insensitively
      even when they're escaped (Andrew)
     </para>
    </listitem>

    <listitem>
     <para>
      Ensure <command>DISCARD</> is handled properly by statement logging (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix incorrect logging of last-completed-transaction time during
      PITR recovery (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Ensure <function>SPI_getvalue</> and <function>SPI_getbinval</>
      behave correctly when the passed tuple and tuple descriptor have
      different numbers of columns (Tom)
     </para>

     <para>
      This situation is normal when a table has had columns added or removed,
      but these two functions didn't handle it properly.
      The only likely consequence is an incorrect error indication.
     </para>
    </listitem>

    <listitem>
     <para>
      Mark <varname>SessionReplicationRole</> as <literal>PGDLLIMPORT</>
      so it can be used by <application>Slony</> on Windows (Magnus)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix small memory leak when using <application>libpq</>'s
      <literal>gsslib</> parameter (Magnus)
     </para>

     <para>
      The space used by the parameter string was not freed at connection
      close.
     </para>
    </listitem>

    <listitem>
     <para>
      Ensure <application>libgssapi</> is linked into <application>libpq</>
      if needed (Markus Schaaf)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <application>ecpg</>'s parsing of <command>CREATE ROLE</> (Michael)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix recent breakage of <literal>pg_ctl restart</> (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Ensure <filename>pg_control</> is opened in binary mode
      (Itagaki Takahiro)
     </para>

     <para>
      <application>pg_controldata</> and <application>pg_resetxlog</>
      did this incorrectly, and so could fail on Windows.
     </para>
    </listitem>

    <listitem>
     <para>
      Update time zone data files to <application>tzdata</> release 2008i (for
      DST law changes in Argentina, Brazil, Mauritius, Syria)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-3-4">
  <title>Release 8.3.4</title>

  <note>
  <title>Release date</title>
  <simpara>2008-09-22</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.3.3.
   For information about new features in the 8.3 major release, see
   <xref linkend="release-8-3">.
  </para>

  <sect2>
   <title>Migration to Version 8.3.4</title>

   <para>
    A dump/restore is not required for those running 8.3.X.
    However, if you are upgrading from a version earlier than 8.3.1,
    see the release notes for 8.3.1.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Fix bug in btree WAL recovery code (Heikki)
     </para>

     <para>
      Recovery failed if the WAL ended partway through a page split operation.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix potential use of wrong cutoff XID for HOT page pruning (Alvaro)
     </para>

     <para>
      This error created a risk of corruption in system
      catalogs that are consulted by <command>VACUUM</>: dead tuple versions
      might be removed too soon.  The impact of this on actual database
      operations would be minimal, since the system doesn't follow MVCC
      rules while examining catalogs, but it might result in transiently
      wrong output from <application>pg_dump</> or other client programs.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix potential miscalculation of <structfield>datfrozenxid</> (Alvaro)
     </para>

     <para>
      This error may explain some recent reports of failure to remove old
      <structname>pg_clog</> data.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix incorrect HOT updates after <structname>pg_class</> is reindexed
      (Tom)
     </para>

     <para>
      Corruption of <structname>pg_class</> could occur if <literal>REINDEX
      TABLE pg_class</> was followed in the same session by an <literal>ALTER
      TABLE RENAME</> or <literal>ALTER TABLE SET SCHEMA</> command.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix missed <quote>combo cid</> case (Karl Schnaitter)
     </para>

     <para>
      This error made rows incorrectly invisible to a transaction in which they
      had been deleted by multiple subtransactions that all aborted.
     </para>
    </listitem>

    <listitem>
     <para>
      Prevent autovacuum from crashing if the table it's currently
      checking is deleted at just the wrong time (Alvaro)
     </para>
    </listitem>

    <listitem>
     <para>
      Widen local lock counters from 32 to 64 bits (Tom)
     </para>

     <para>
      This responds to reports that the counters could overflow in
      sufficiently long transactions, leading to unexpected <quote>lock is
      already held</> errors.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible duplicate output of tuples during a GiST index scan (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Regenerate foreign key checking queries from scratch when either
      table is modified (Tom)
     </para>

     <para>
      Previously, 8.3 would attempt to replan the query, but would work from
      previously generated query text.  This led to failures if a
      table or column was renamed.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix missed permissions checks when a view contains a simple
      <literal>UNION ALL</> construct (Heikki)
     </para>

     <para>
      Permissions for the referenced tables were checked properly, but not
      permissions for the view itself.
     </para>
    </listitem>

    <listitem>
     <para>
      Add checks in executor startup to ensure that the tuples produced by an
      <command>INSERT</> or <command>UPDATE</> will match the target table's
      current rowtype (Tom)
     </para>

     <para>
      This situation is believed to be impossible in 8.3, but it can happen in
      prior releases, so a check seems prudent.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible repeated drops during <command>DROP OWNED</> (Tom)
     </para>

     <para>
      This would typically result in strange errors such as <quote>cache
      lookup failed for relation NNN</>.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix several memory leaks in XML operations (Kris Jurka, Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <function>xmlserialize()</> to raise error properly for
      unacceptable target data type (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix a couple of places that mis-handled multibyte characters in text
      search configuration file parsing (Tom)
     </para>

     <para>
      Certain characters occurring in configuration files would always cause
      <quote>invalid byte sequence for encoding</> failures.
     </para>
    </listitem>

    <listitem>
     <para>
      Provide file name and line number location for all errors reported
      in text search configuration files (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <literal>AT TIME ZONE</> to first try to interpret its timezone
      argument as a timezone abbreviation, and only try it as a full timezone
      name if that fails, rather than the other way around as formerly (Tom)
     </para>

     <para>
      The timestamp input functions have always resolved ambiguous zone names
      in this order.  Making <literal>AT TIME ZONE</> do so as well improves
      consistency, and fixes a compatibility bug introduced in 8.1:
      in ambiguous cases we now behave the same as 8.0 and before did,
      since in the older versions <literal>AT TIME ZONE</> accepted
      <emphasis>only</> abbreviations.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix datetime input functions to correctly detect integer overflow when
      running on a 64-bit platform (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Prevent integer overflows during units conversion when displaying a
      configuration parameter that has units (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Improve performance of writing very long log messages to syslog (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Allow spaces in the suffix part of an LDAP URL in
      <filename>pg_hba.conf</> (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix bug in backwards scanning of a cursor on a <literal>SELECT DISTINCT
      ON</> query (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix planner bug that could improperly push down <literal>IS NULL</>
      tests below an outer join (Tom)
     </para>

     <para>
      This was triggered by occurrence of <literal>IS NULL</> tests for
      the same relation in all arms of an upper <literal>OR</> clause.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix planner bug with nested sub-select expressions (Tom)
     </para>

     <para>
      If the outer sub-select has no direct dependency on the parent query,
      but the inner one does, the outer value might not get recalculated
      for new parent query rows.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix planner to estimate that <literal>GROUP BY</> expressions yielding
      boolean results always result in two groups, regardless of the
      expressions' contents (Tom)
     </para>

     <para>
      This is very substantially more accurate than the regular <literal>GROUP
      BY</> estimate for certain boolean tests like <replaceable>col</>
      <literal>IS NULL</>.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix PL/PgSQL to not fail when a <literal>FOR</> loop's target variable
      is a record containing composite-type fields (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix PL/Tcl to behave correctly with Tcl 8.5, and to be more careful
      about the encoding of data sent to or from Tcl (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Improve performance of <function>PQescapeBytea()</> (Rudolf Leitgeb)
     </para>
    </listitem>

    <listitem>
     <para>
      On Windows, work around a Microsoft bug by preventing
      <application>libpq</> from trying to send more than 64kB per system call
      (Magnus)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <application>ecpg</> to handle variables properly in <command>SET</>
      commands (Michael)
     </para>
    </listitem>

    <listitem>
     <para>
      Improve <application>pg_dump</> and <application>pg_restore</>'s
      error reporting after failure to send a SQL command (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <application>pg_ctl</> to properly preserve postmaster
      command-line arguments across a <literal>restart</> (Bruce)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix erroneous WAL file cutoff point calculation in
      <application>pg_standby</> (Simon)
     </para>
    </listitem>

    <listitem>
     <para>
      Update time zone data files to <application>tzdata</> release 2008f (for
      DST law changes in Argentina, Bahamas, Brazil, Mauritius, Morocco,
      Pakistan, Palestine, and Paraguay)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-3-3">
  <title>Release 8.3.3</title>

  <note>
  <title>Release date</title>
  <simpara>2008-06-12</simpara>
  </note>

  <para>
   This release contains one serious and one minor bug fix over 8.3.2.
   For information about new features in the 8.3 major release, see
   <xref linkend="release-8-3">.
  </para>

  <sect2>
   <title>Migration to Version 8.3.3</title>

   <para>
    A dump/restore is not required for those running 8.3.X.
    However, if you are upgrading from a version earlier than 8.3.1,
    see the release notes for 8.3.1.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Make <function>pg_get_ruledef()</> parenthesize negative constants (Tom)
     </para>

     <para>
      Before this fix, a negative constant in a view or rule might be dumped
      as, say, <literal>-42::integer</>, which is subtly incorrect: it should
      be <literal>(-42)::integer</> due to operator precedence rules.
      Usually this would make little difference, but it could interact with
      another recent patch to cause
      <productname>PostgreSQL</> to reject what had been a valid
      <command>SELECT DISTINCT</> view query.  Since this could result in
      <application>pg_dump</> output failing to reload, it is being treated
      as a high-priority fix.  The only released versions in which dump
      output is actually incorrect are 8.3.1 and 8.2.7.
     </para>
    </listitem>

    <listitem>
     <para>
      Make <command>ALTER AGGREGATE ... OWNER TO</> update
      <structname>pg_shdepend</> (Tom)
     </para>

     <para>
      This oversight could lead to problems if the aggregate was later
      involved in a <command>DROP OWNED</> or <command>REASSIGN OWNED</>
      operation.
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-3-2">
  <title>Release 8.3.2</title>

  <note>
  <title>Release date</title>
  <simpara>never released</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.3.1.
   For information about new features in the 8.3 major release, see
   <xref linkend="release-8-3">.
  </para>

  <sect2>
   <title>Migration to Version 8.3.2</title>

   <para>
    A dump/restore is not required for those running 8.3.X.
    However, if you are upgrading from a version earlier than 8.3.1,
    see the release notes for 8.3.1.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Fix <literal>ERRORDATA_STACK_SIZE exceeded</literal> crash that
      occurred on Windows when using UTF-8 database encoding and a different
      client encoding (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix incorrect archive truncation point calculation for the
      <literal>%r</> macro in <varname>recovery_command</> parameters
      (Simon)
     </para>

     <para>
      This could lead to data loss if a warm-standby script relied on
      <literal>%r</> to decide when to throw away WAL segment files.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <command>ALTER TABLE ADD COLUMN ... PRIMARY KEY</> so that the new
      column is correctly checked to see if it's been initialized to all
      non-nulls (Brendan Jurd)
     </para>

     <para>
      Previous versions neglected to check this requirement at all.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <command>REASSIGN OWNED</> so that it works on procedural
      languages too (Alvaro)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix problems with <command>SELECT FOR UPDATE/SHARE</> occurring as a
      subquery in a query with a non-<command>SELECT</> top-level operation
      (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible <command>CREATE TABLE</> failure when inheriting the
      <quote>same</> constraint from multiple parent relations that
      inherited that constraint from a common ancestor (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <function>pg_get_ruledef()</> to show the alias, if any, attached
      to the target table of an <command>UPDATE</> or <command>DELETE</>
      (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Restore the pre-8.3 behavior that an out-of-range block number in a
      TID being used in a TidScan plan results in silently not matching any
      rows (Tom)
     </para>

     <para>
      8.3.0 and 8.3.1 threw an error instead.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix GIN bug that could result in a <literal>too many LWLocks
      taken</literal> failure (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix broken GiST comparison function for <type>tsquery</> (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <function>tsvector_update_trigger()</> and <function>ts_stat()</>
      to accept domains over the types they expect to work with (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix failure to support enum data types as foreign keys (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Avoid possible crash when decompressing corrupted data
      (Zdenek Kotala)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix race conditions between delayed unlinks and <command>DROP
      DATABASE</> (Heikki)
     </para>

     <para>
      In the worst case this could result in deleting a newly created table
      in a new database that happened to get the same OID as the
      recently-dropped one; but of course that is an extremely
      low-probability scenario.
     </para>
    </listitem>

    <listitem>
     <para>
      Repair two places where SIGTERM exit of a backend could leave corrupted
      state in shared memory (Tom)
     </para>

     <para>
      Neither case is very important if SIGTERM is used to shut down the
      whole database cluster together, but there was a problem if someone
      tried to SIGTERM individual backends.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible crash due to incorrect plan generated for an
      <literal><replaceable>x</> IN (SELECT <replaceable>y</>
      FROM ...)</literal> clause when <replaceable>x</> and <replaceable>y</>
      have different data types; and make sure the behavior is semantically
      correct when the conversion from <replaceable>y</>'s type to
      <replaceable>x</>'s type is lossy (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix oversight that prevented the planner from substituting known Param
      values as if they were constants (Tom)
     </para>

     <para>
      This mistake partially disabled optimization of unnamed
      extended-Query statements in 8.3.0 and 8.3.1: in particular the
      LIKE-to-indexscan optimization would never be applied if the LIKE
      pattern was passed as a parameter, and constraint exclusion
      depending on a parameter value didn't work either.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix planner failure when an indexable <function>MIN</> or
      <function>MAX</> aggregate is used with <literal>DISTINCT</> or
      <literal>ORDER BY</> (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix planner to ensure it never uses a <quote>physical tlist</> for a
      plan node that is feeding a Sort node (Tom)
     </para>

     <para>
      This led to the sort having to push around more data than it really
      needed to, since unused column values were included in the sorted
      data.
     </para>
    </listitem>

    <listitem>
     <para>
      Avoid unnecessary copying of query strings (Tom)
     </para>

     <para>
      This fixes a performance problem introduced in 8.3.0 when a very large
      number of commands are submitted as a single query string.
     </para>
    </listitem>

    <listitem>
     <para>
      Make <function>TransactionIdIsCurrentTransactionId()</> use binary
      search instead of linear search when checking child-transaction XIDs
      (Heikki)
     </para>

     <para>
      This fixes some cases in which 8.3.0 was significantly
      slower than earlier releases.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix conversions between ISO-8859-5 and other encodings to handle
      Cyrillic <quote>Yo</> characters (<literal>e</> and <literal>E</> with
      two dots) (Sergey Burladyan)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix several datatype input functions, notably <function>array_in()</>,
      that were allowing unused bytes in their results to contain
      uninitialized, unpredictable values (Tom)
     </para>

     <para>
      This could lead to failures in which two apparently identical literal
      values were not seen as equal, resulting in the parser complaining
      about unmatched <literal>ORDER BY</> and <literal>DISTINCT</>
      expressions.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix a corner case in regular-expression substring matching
      (<literal>substring(<replaceable>string</> from
      <replaceable>pattern</>)</literal>) (Tom)
     </para>

     <para>
      The problem occurs when there is a match to the pattern overall but
      the user has specified a parenthesized subexpression and that
      subexpression hasn't got a match.  An example is
      <literal>substring('foo' from 'foo(bar)?')</>.
      This should return NULL, since <literal>(bar)</> isn't matched, but
      it was mistakenly returning the whole-pattern match instead (ie,
      <literal>foo</>).
     </para>
    </listitem>

    <listitem>
     <para>
      Prevent cancellation of an auto-vacuum that was launched to prevent
      XID wraparound (Alvaro)
     </para>
    </listitem>

    <listitem>
     <para>
      Improve <command>ANALYZE</>'s handling of in-doubt tuples (those
      inserted or deleted by a not-yet-committed transaction) so that the
      counts it reports to the stats collector are more likely to be correct
      (Pavan Deolasee)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <application>initdb</> to reject a relative path for its
      <literal>--xlogdir</> (<literal>-X</>) option (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Make <application>psql</> print tab characters as an appropriate
      number of spaces, rather than <literal>\x09</literal> as was done in
      8.3.0 and 8.3.1 (Bruce)
     </para>
    </listitem>

    <listitem>
     <para>
      Update time zone data files to <application>tzdata</> release 2008c (for
      DST law changes in Morocco, Iraq, Choibalsan, Pakistan, Syria, Cuba, and
      Argentina/San_Luis)
     </para>
    </listitem>

    <listitem>
     <para>
      Add <function>ECPGget_PGconn()</> function to
      <application>ecpglib</> (Michael)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix incorrect result from <application>ecpg</>'s
      <function>PGTYPEStimestamp_sub()</> function (Michael)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix handling of continuation line markers in <application>ecpg</>
      (Michael)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible crashes in <filename>contrib/cube</> functions (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix core dump in <filename>contrib/xml2</>'s
      <function>xpath_table()</> function when the input query returns a
      NULL value (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <filename>contrib/xml2</>'s makefile to not override
      <literal>CFLAGS</>, and make it auto-configure properly for
      <application>libxslt</> present or not (Tom)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-8-3-1">
  <title>Release 8.3.1</title>

  <note>
  <title>Release date</title>
  <simpara>2008-03-17</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 8.3.0.
   For information about new features in the 8.3 major release, see
   <xref linkend="release-8-3">.
  </para>

  <sect2>
   <title>Migration to Version 8.3.1</title>

   <para>
    A dump/restore is not required for those running 8.3.X.
    However, you might need to <command>REINDEX</> indexes on textual
    columns after updating, if you are affected by the Windows locale
    issue described below.
   </para>

  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

    <listitem>
     <para>
      Fix character string comparison for Windows locales that consider
      different character combinations as equal (Tom)
     </para>

     <para>
      This fix applies only on Windows and only when using UTF-8
      database encoding.  The same fix was made for all other cases
      over two years ago, but Windows with UTF-8 uses a separate code
      path that was not updated.  If you are using a locale that
      considers some non-identical strings as equal, you may need to
      <command>REINDEX</> to fix existing indexes on textual columns.
     </para>
    </listitem>

    <listitem>
     <para>
      Repair corner-case bugs in <command>VACUUM FULL</> (Tom)
     </para>

     <para>
      A potential deadlock between concurrent <command>VACUUM FULL</>
      operations on different system catalogs was introduced in 8.2.
      This has now been corrected.  8.3 made this worse because the
      deadlock could occur within a critical code section, making it
      a PANIC rather than just ERROR condition.
     </para>

     <para>
      Also, a <command>VACUUM FULL</> that failed partway through
      vacuuming a system catalog could result in cache corruption in
      concurrent database sessions.
     </para>

     <para>
      Another <command>VACUUM FULL</> bug introduced in 8.3 could
      result in a crash or out-of-memory report when dealing with
      pages containing no live tuples.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix misbehavior of foreign key checks involving <type>character</>
      or <type>bit</> columns (Tom)
     </para>

     <para>
      If the referencing column were of a different but compatible type
      (for instance <type>varchar</>), the constraint was enforced incorrectly.
     </para>
    </listitem>

    <listitem>
     <para>
      Avoid needless deadlock failures in no-op foreign-key checks (Stephan
      Szabo, Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible core dump when re-planning a prepared query (Tom)
     </para>

     <para>
      This bug affected only protocol-level prepare operations, not
      SQL <command>PREPARE</>, and so tended to be seen only with
      JDBC, DBI, and other client-side drivers that use prepared
      statements heavily.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix possible failure when re-planning a query that calls an SPI-using
      function (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix failure in row-wise comparisons involving columns of different
      datatypes (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix longstanding <command>LISTEN</>/<command>NOTIFY</>
      race condition (Tom)
     </para>

     <para>
      In rare cases a session that had just executed a
      <command>LISTEN</> might not get a notification, even though
      one would be expected because the concurrent transaction executing
      <command>NOTIFY</> was observed to commit later.
     </para>

     <para>
      A side effect of the fix is that a transaction that has executed
      a not-yet-committed <command>LISTEN</> command will not see any
      row in <structname>pg_listener</> for the <command>LISTEN</>,
      should it choose to look; formerly it would have.  This behavior
      was never documented one way or the other, but it is possible that
      some applications depend on the old behavior.
     </para>
    </listitem>

    <listitem>
     <para>
      Disallow <command>LISTEN</> and <command>UNLISTEN</> within a
      prepared transaction (Tom)
     </para>

     <para>
      This was formerly allowed but trying to do it had various unpleasant
      consequences, notably that the originating backend could not exit
      as long as an <command>UNLISTEN</> remained uncommitted.
     </para>
    </listitem>

    <listitem>
     <para>
      Disallow dropping a temporary table within a
      prepared transaction (Heikki)
     </para>

     <para>
      This was correctly disallowed by 8.1, but the check was inadvertently
      broken in 8.2 and 8.3.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix rare crash when an error occurs during a query using a hash index
      (Heikki)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix incorrect comparison of <type>tsquery</> values (Teodor)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix incorrect behavior of <literal>LIKE</> with non-ASCII characters
      in single-byte encodings (Rolf Jentsch)
     </para>
    </listitem>

    <listitem>
     <para>
      Disable <function>xmlvalidate</> (Tom)
     </para>

     <para>
      This function should have been removed before 8.3 release, but
      was inadvertently left in the source code.  It poses a small
      security risk since unprivileged users could use it to read the
      first few characters of any file accessible to the server.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix memory leaks in certain usages of set-returning functions (Neil)
     </para>
    </listitem>

    <listitem>
     <para>
      Make <function>encode(<replaceable>bytea</>, 'escape')</> convert all
      high-bit-set byte values into <literal>\</><replaceable>nnn</> octal
      escape sequences (Tom)
     </para>

     <para>
      This is necessary to avoid encoding problems when the database
      encoding is multi-byte.  This change could pose compatibility issues
      for applications that are expecting specific results from
      <function>encode</>.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix input of datetime values for February 29 in years BC (Tom)
     </para>

     <para>
      The former coding was mistaken about which years were leap years.
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <quote>unrecognized node type</> error in some variants of
      <command>ALTER OWNER</> (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Avoid tablespace permissions errors in <command>CREATE TABLE LIKE
      INCLUDING INDEXES</> (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Ensure <structname>pg_stat_activity</>.<structfield>waiting</> flag
      is cleared when a lock wait is aborted (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix handling of process permissions on Windows Vista (Dave, Magnus)
     </para>

     <para>
      In particular, this fix allows starting the server as the Administrator
      user.
     </para>
    </listitem>

    <listitem>
     <para>
      Update time zone data files to <application>tzdata</> release 2008a
      (in particular, recent Chile changes); adjust timezone abbreviation
      <literal>VET</> (Venezuela) to mean UTC-4:30, not UTC-4:00 (Tom)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <application>ecpg</> problems with arrays (Michael)
     </para>
    </listitem>

    <listitem>
     <para>
      Fix <application>pg_ctl</> to correctly extract the postmaster's port
      number from command-line options (Itagaki Takahiro, Tom)
     </para>

     <para>
      Previously, <literal>pg_ctl start -w</> could try to contact the
      postmaster on the wrong port, leading to bogus reports of startup
      failure.
     </para>
    </listitem>

    <listitem>
     <para>
      Use <option>-fwrapv</> to defend against possible misoptimization
      in recent <application>gcc</> versions (Tom)
     </para>

     <para>
      This is known to be necessary when building <productname>PostgreSQL</>
      with <application>gcc</> 4.3 or later.
     </para>
    </listitem>

    <listitem>
     <para>
      Enable building <filename>contrib/uuid-ossp</> with MSVC (Hiroshi Saito)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

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

  <note>
   <title>Release date</title>
   <simpara>2008-02-04</simpara>
  </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 and <command>DELETE</>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 database or 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>, using asynchronous commit does not put
       database consistency at risk; the worst case is that after a crash the
       last few reportedly-committed transactions might not be committed after
       all.
       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 and <command>DELETE</>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 automatically reclaimed at
       the time of <command>INSERT</> or <command>UPDATE</> 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</>.  The <varname>synchronize_seqscans</>
       configuration parameter can be used to disable this if necessary.
      </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>
       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>
       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>
       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>
       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>
       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>
       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>

     <listitem>
      <para>
       Prevent <command>COPY</> from using digits and lowercase letters as
       delimiters (Tom)
      </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>

     <listitem>
      <para>
       Remove <literal>-u</> option (this option has long been deprecated)
       (Tom)
      </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>

     <listitem>
      <para>
       Remove <literal>-u</> option (this option has long been deprecated)
       (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>

     <listitem>
      <para>
       Add documentation about preventing database server spoofing when
       the server is down (Bruce)
      </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>
