<!-- doc/src/sgml/release-10.sgml -->
<!-- See header comment in release.sgml about typical markup -->

 <sect1 id="release-10">
  <title>Release 10</title>

  <formalpara>
   <title>Release date:</title>
   <para>2017-09-XX (CURRENT AS OF 2017-05-14)</para>
  </formalpara>

  <sect2>
   <title>Overview</title>

   <para>
    Major enhancements in <productname>PostgreSQL</> 10 include:
   </para>

   <!-- Items in this list summarize one or more items below -->

   <itemizedlist>

   <listitem><para> </para></listitem>
   </itemizedlist>

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

  </sect2>

  <sect2>

  <title>Migration to Version 10</title>

   <para>
    A dump/restore using <xref linkend="app-pg-dumpall">, or use of <xref
    linkend="pgupgrade">, is required for those wishing to migrate data
    from any previous release.
   </para>

   <para>
    Version 10 contains a number of changes that may affect compatibility
    with previous releases.  Observe the following incompatibilities:
   </para>

   <itemizedlist>

    <listitem>
<!--
2017-04-03 [ea69a0dea] Expand hash indexes more gradually.
-->
     <para>
      <application>pg_upgrade</>-ed hash indexes from previous major
      PostgreSQL versions must be rebuilt.
     </para>

     <para>
      Major hash storage improvements necessitated this requirement.
     </para>
    </listitem>

    <listitem>
<!--
2017-03-27 [3371e4d9b] Change default of log_directory to 'log'
-->
     <para>
      Change the default <link linkend="guc-log-destination">log
      directory</> from <filename>pg_log</> to <filename>log</> (Andreas
      Karlsson)
     </para>
    </listitem>

    <listitem>
<!--
2016-10-20 [f82ec32ac] Rename "pg_xlog" directory to "pg_wal"
-->
     <para>
      Rename <filename>pg_xlog</> to <link
      linkend="wal"><filename>pg_wal</></> (Michael Paquier)
     </para>

     <para>
      This prevents the write-ahead log directory from being confused as
      containing server activity logs, and erroneously truncated.
     </para>
    </listitem>

    <listitem>
<!--
2017-02-09 [806091c96] Remove all references to "xlog" from SQL-callable functi
2017-02-09 [85c11324c] Rename user-facing tools with "xlog" in the name to say
2017-02-09 [62e8b3875] Rename command line options for ongoing xlog -> wal conv
2017-02-15 [0dfa89ba2] Replace reference to "xlog-method" with "wal-method" in
-->
     <para>
      Rename <acronym>SQL</> functions, tools, and options that reference
      <quote>xlog</> to <quote>wal</> (Robert Haas)
     </para>

     <para>
      For example, <function>pg_switch_xlog()</> becomes
      <function>pg_switch_wal()</>, <application>pg_receivexlog</>
      becomes <application>pg_receivewal</>, and <option>--xlogdir</>
      becomes <option>--waldir</>.  This might require adjustments for
      prior-version scripts.
     </para>
    </listitem>

    <listitem>
<!--
2017-03-17 [88e66d193] Rename "pg_clog" directory to "pg_xact".
-->
     <para>
      Rename transaction status directory <filename>pg_clog</> directory
      to <filename>pg_xact</> (Michael Paquier)
     </para>
    </listitem>

    <listitem>
<!--
2017-05-11 [d10c626de] Rename WAL-related functions and views to use "lsn" not
-->
     <para>
      Rename <acronym>WAL</>-related functions and views to use <literal>lsn</>
      instead of <literal>location</> (David Rowley)
     </para>
    </listitem>

    <listitem>
<!--
2017-01-16 [d43a619c6] Fix check_srf_call_placement() to handle VALUES cases co
2017-01-18 [69f4b9c85] Move targetlist SRF handling from expression evaluation
2017-01-18 [f13a1277a] Doc: improve documentation of new SRF-in-tlist behavior.
2017-06-13 [0436f6bde] Disallow set-returning functions inside CASE or COALESCE
-->
     <para>
      Change the implementation of set-returning functions appearing in
      a query's <literal>SELECT</> list (Andres Freund)
     </para>

     <para>
      Set-returning functions are now evaluated before evaluation of scalar
      expressions in the <literal>SELECT</> list, much as though they had
      been placed in a <literal>LATERAL FROM</>-clause item.  This allows
      saner semantics for cases where multiple set-returning functions are
      present.  If they return different numbers of rows, the shorter results
      are extended to match the longest result by adding nulls.  Previously
      the results were cycled until they all terminated at the same time,
      producing a number of rows equal to the least common multiple of the
      functions' periods.  In addition, set-returning functions are now
      disallowed within <literal>CASE</> and <literal>COALESCE</> constructs.
      For more information
      see <xref linkend="xfunc-sql-functions-returning-set">.
     </para>
    </listitem>

    <listitem>
<!--
2017-01-04 [9a4d51077] Make wal streaming the default mode for pg_basebackup
-->
     <para>
      Have <application><xref linkend="app-pgbasebackup"></> stream the
      <acronym>WAL</> needed to restore the backup by default (Magnus
      Hagander)
     </para>

     <para>
      This changes the <application>pg_basebackup</>
      <option>-X</>/<option>--xlog-method</> default to <literal>stream</>.
      An option value <literal>none</> has been added to recreate the old
      behavior.  The <application>pg_basebackup</> option <option>-x</>
      has been removed (use <option>-X</> fetch).
     </para>
    </listitem>

    <listitem>
<!--
2017-02-13 [8df9bd0b4] Change logical replication pg_hba.conf use
-->
     <para>
      Change how logical replication
      uses <link linkend="auth-pg-hba-conf"><filename>pg_hba.conf</filename></link>.
     </para>

     <para>
      In previous releases, a logical replication connection required
      the <literal>replication</literal> keyword in the database column.  As
      of this release, logical replication matches a normal entry with a
      database name or keywords such as <literal>all</literal>.  Physical
      replication continues to use the <literal>replication</literal> keyword.
      Since built-in logical replication is new in this release as well, this
      change only affects users of third-party logical replication plugins.
     </para>
    </listitem>

    <listitem>
<!--
2017-01-14 [05cd12ed5] pg_ctl: Change default to wait for all actions
-->
    <para>
     Make all <application><xref linkend="app-pg-ctl"></> actions wait
     by default for completion (Peter Eisentraut)
    </para>

    <para>
     Previously some <application>pg_ctl</> actions didn't wait for
     completion, and required the use of <option>-w</> to do so.
    </para>
    </listitem>

    <listitem>
<!--
2017-05-08 [eb61136dc] Remove support for password_encryption='off' / 'plain'.
-->
    <para>
     Remove the ability to store unencrypted passwords on the server
     (Heikki Linnakangas)
    </para>

    <para>
     The server-side variable <xref linkend="guc-password-encryption">
     no longer supports <literal>off</> or <literal>plain</>.
     The <literal>UNENCRYPTED</> option is no longer supported for
     <command>CREATE/ALTER USER ... PASSSWORD</>.  Similarly, the
     <option>--unencrypted</> has been removed from <command>createuser</>.
     The default for <option>password_encryption</> is still
     <literal>md5</>, and users migrating passwords from older systems
     will have them stored encrypted by default in this release.
    </para>
    </listitem>

    <listitem>
<!--
2016-10-26 [94aceed31] Support multi-dimensional arrays in PL/python.
2016-10-26 [cfd9c87a5] Only treat Python Lists as array dimensions.
-->
    <para>
     Allow multi-dimensional arrays to be passed into PL/Python functions,
     and returned as nested Python lists (Alexey Grishchenko, Dave Cramer,
     Heikki Linnakangas)
    </para>

    <para>
     This makes a backwards-incompatible change to the handling of
     composite types in arrays. Previously, you could return an array of
     composite types as "[[col1, col2], [col1, col2]]", but now that is
     interpreted as a two- dimensional array. Composite types in arrays
     must now be returned as Python tuples, not lists, to resolve the
     ambiguity. I.e. "[(col1, col2), (col1, col2)]".  See the documentation
     for more details. CLARIFY
    </para>
    </listitem>

    <listitem>
<!--
2017-02-27 [817f2a586] Remove PL/Tcl's "module" facility.
-->
    <para>
     Remove PL/Tcl's "module" auto-loading facility (Tom Lane)
    </para>

    <para>
     Replaced by new PL/Tcl startup <acronym>GUC</>s.
    </para>
    </listitem>

    <listitem>
<!--
2016-12-23 [e13486eba] Remove sql_inheritance GUC.
-->
    <para>
     Remove <varname>sql_inheritance</> <acronym>GUC</> (Robert Haas)
    </para>

    <para>
     Changing this from the default value caused queries referencing
     parent tables to not include children tables.  The <acronym>SQL</>
     standard requires such behavior and this has been the default since
     PostgreSQL 7.1.
    </para>
    </listitem>

    <listitem>
<!--
2017-02-15 [51ee6f316] Replace min_parallel_relation_size with two new GUCs.
-->
    <para>
     Add <acronym>GUC</>s <xref linkend="guc-min-parallel-table-scan-size">
     and <xref linkend="guc-min-parallel-index-scan-size"> to control
     parallel operation (Amit Kapila, Robert Haas)
    </para>

    <para>
     This replaces <varname>min_parallel_relation_size</>, which was
     too generic.
    </para>
    </listitem>

    <listitem>
<!--
2016-10-12 [64f3524e2] Remove pg_dump/pg_dumpall support for dumping from pre-8
-->
    <para>
     Remove <application>pg_dump</>/<application>pg_dumpall</> support
     for dumping from pre-8.0 servers (Tom Lane)
    </para>

     <para>
      Users needing dump support for pre-8.0 servers need to use dump
      binaries from PostgreSQL 9.6.
     </para>
    </listitem>

    <listitem>
<!--
2017-02-23 [b6aa17e0a] De-support floating-point timestamps.
-->
     <para>
      Remove support for floating-point datetimes/timestamps (Tom Lane)
     </para>

     <para>
      This removes configure's <option>--disable-integer-datetimes</>
      option.  Floating-point datetimes/timestamps have not been the
      default since PostgreSQL 8.3 and have few advantages.
     </para>
    </listitem>

    <listitem>
<!--
2016-10-11 [2f1eaf87e] Drop server support for FE/BE protocol version 1.0.
-->
     <para>
      Remove support for client/server protocol version 1.0 (Tom Lane)
     </para>

     <para>
      This protocol hasn't had client support since PostgreSQL 6.3.
     </para>
    </listitem>

    <listitem>
<!--
2017-02-13 [7ada2d31f] Remove contrib/tsearch2.
-->
     <para>
      Remove contrib/tsearch2 (Robert Haas)
     </para>

     <para>
      This removes compatibility with the contrib version of full text
      search that shipped in pre-8.3 PostgreSQL versions.
    </para>
    </listitem>

    <listitem>
<!--
2017-03-23 [50c956add] Remove createlang and droplang
-->
     <para>
      Remove createlang and droplang command-line applications (Peter
      Eisentraut)
     </para>
    </listitem>

    <listitem>
<!--
2017-03-30 [5ded4bd21] Remove support for version-0 calling conventions.
-->
     <para>
      Remove support for version-0 function calling conventions (Andres
      Freund)
     </para>
    </listitem>

    <listitem>
<!--
2016-10-11 [2b860f52e] Remove "sco" and "unixware" ports.
-->
     <para>
      Remove <systemitem class="osname">SCO</> and <systemitem
      class="osname">Unixware</> ports (Tom Lane)
     </para>
    </listitem>

   </itemizedlist>

  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    Below you will find a detailed account of the changes between
   <productname>PostgreSQL</productname> 10 and the previous major
    release.
   </para>

   <sect3>
    <title>Server</title>

    <sect4>
     <title>Parallel Queries</title>

     <itemizedlist>

      <listitem>
<!--
2017-02-15 [569174f1b] btree: Support parallel index scans.
2017-02-15 [5262f7a4f] Add optimizer and executor support for parallel index sc
2017-02-19 [0414b26ba] Add optimizer and executor support for parallel index-on
-->
       <para>
        Support parallel B-tree index scans (Rahila Syed, Amit Kapila,
        Robert Haas, Rafia Sabih)
       </para>

       <para>
        Allows B-tree index pages to be checked by separate parallel
        workers.
       </para>
      </listitem>

      <listitem>
<!--
2017-03-08 [98e6e8904] tidbitmap: Support shared iteration.
2017-03-08 [f35742ccb] Support parallel bitmap heap scans.
-->
       <para>
        Support parallel bitmap heap scans (Dilip Kumar)
       </para>

       <para>
        This allows a single index scan to dispatch parallel workers to
        process different areas of the heap.
       </para>
      </listitem>

      <listitem>
<!--
2017-03-07 [3bc7dafa9] Consider parallel merge joins.
-->
       <para>
        Allow merge joins to be performed in parallel (Dilip Kumar)
       </para>
      </listitem>

      <listitem>
<!--
2017-02-14 [5e6d8d2bb] Allow parallel workers to execute subplans.
-->
       <para>
        Allow non-correlated subqueries to be run in parallel (Amit Kapila)
       </para>
      </listitem>

      <listitem>
<!--
2017-03-09 [355d3993c] Add a Gather Merge executor node.
-->
       <para>
        Improve ability of parallel workers to return pre-sorted data
        (Rushabh Lathia)
       </para>
      </listitem>

      <listitem>
<!--
2017-03-24 [61c2e1a95] Improve access to parallel query from procedural languag
-->
       <para>
        Increase parallel query usage in procedural language functions
        (Robert Haas, Rafia Sabih)
       </para>
      </listitem>

      <listitem>
<!--
2016-12-02 [b460f5d66] Add max_parallel_workers GUC.
2016-12-05 [2b959d495] Reduce the default for max_worker_processes back to 8.
-->
       <para>
        Add <acronym>GUC</> <xref linkend="guc-max-parallel-workers">
        to limit the number of worker processes that can be used for
        query parallelism (Julien Rouhaud)
       </para>

       <para>
        This can be set lower than <xref
        linkend="guc-max-worker-processes"> to reserve worker processes
        for purposes other than parallel queries.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Indexes</title>

     <itemizedlist>

      <listitem>
<!--
2016-08-23 [77e290682] Create an SP-GiST opclass for inet/cidr.
-->
       <para>
        Add <acronym>SP-GiST</> index support for <type>INET</> and
        <type>CIDR</> data types (Emre Hasegeli)
       </para>

       <para>
        These data types already had GiST support.
       </para>
      </listitem>

      <listitem>
<!--
2017-03-23 [218f51584] Reduce page locking in GIN vacuum
-->
       <para>
        Reduce page locking during vacuuming of <acronym>GIN</> indexes
        (Andrey Borodin)
       </para>
      </listitem>

      <listitem>
<!--
2017-04-01 [7526e1022] BRIN auto-summarization
-->
       <para>
        Add option to allow <acronym>BRIN</> index summarization to happen
        more aggressively (&Aacute;lvaro Herrera)
       </para>

       <para>
        Specifically, a new <link linkend="SQL-CREATEINDEX"><command>CREATE
        INDEX</></> option allows auto-summarizion of the
        previous <acronym>BRIN</> page range when a new page
        range is created.
       </para>
      </listitem>

      <listitem>
<!--
2017-04-01 [c655899ba] BRIN de-summarization
-->
       <para>
        Add functions to remove and re-add <acronym>BRIN</>
        summarization for <acronym>BRIN</> index ranges (&Aacute;lvaro
        Herrera)
       </para>

       <para>
        New <acronym>SQL</> function <link
        linkend="functions-admin-index-table"><function>brin_summarize_range()</></>
        updates <acronym>BRIN</> index summarization for a specified
        range and <function>brin_desummarize_range()</> removes it.
        This is helpful to update summarization of a range that is now
        smaller due to <command>UPDATE</>s and <command>DELETE</>s.
       </para>
      </listitem>

      <listitem>
<!--
2017-04-06 [7e534adcd] Fix BRIN cost estimation
-->
       <para>
        Improve accuracy in determining if a <acronym>BRIN</> index scan
        is beneficial (David Rowley, Emre Hasegeli)
       </para>
      </listitem>

      <listitem>
<!--
2016-09-09 [b1328d78f] Invent PageIndexTupleOverwrite, and teach BRIN and GiST
-->
       <para>
        Allow faster <acronym>GiST</> inserts and updates by reusing
        index space more efficiently (Andrey Borodin)
       </para>
      </listitem>

     </itemizedlist>

     <sect5>
      <title><link linkend="indexes-types">Hash Indexes</link></title>

      <itemizedlist>

       <listitem>
<!--
2017-02-27 [30df93f69] hash: Refactor overflow page allocation.
2017-03-14 [c11453ce0] hash: Add write-ahead logging support.
2017-02-27 [b0f18cb77] hash: Refactor bucket squeeze code.
-->
        <para>
         Add write-ahead logging support to hash indexes (Amit Kapila)
        </para>

        <para>
         This makes hash indexes crash-safe and replicated, and removes
         the warning message about their use.
        </para>
       </listitem>

       <listitem>
<!--
2016-11-30 [6d46f4783] Improve hash index bucket split behavior.
2017-02-07 [293e24e50] Cache hash index's metapage in rel->rd_amcache.
-->
        <para>
         Improve hash bucket split performance by reducing locking
         requirements (Amit Kapila, Mithun Cy)
        </para>

        <para>
         Also cache hash index meta-information for faster lookups.
        </para>
       </listitem>

       <listitem>
<!--
2017-04-03 [ea69a0dea] Expand hash indexes more gradually.
-->
        <para>
         Improve efficiency of hash index growth (Amit Kapila, Mithun Cy)
        </para>
       </listitem>

       <listitem>
<!--
2017-03-15 [6977b8b7f] Port single-page btree vacuum logic to hash indexes.
-->
        <para>
         Allow single-page hash pruning (Ashutosh Sharma)
        </para>
       </listitem>

      </itemizedlist>

     </sect5>

    </sect4>

    <sect4>

     <title>Locking</title>

     <itemizedlist>

      <listitem>
<!--
2017-03-31 [64d4da511] For foreign keys, check REFERENCES privilege only on the
-->
       <para>
        Only check for <literal>REFERENCES</> permission on referenced
        tables (Tom Lane)
       </para>

       <para>
        Previously <literal>REFERENCES</> permission on the referencing
        table was also required.
       </para>
      </listitem>

      <listitem>
<!--
2016-09-05 [15bc038f9] Relax transactional restrictions on ALTER TYPE ... ADD V
-->
       <para>
        Reduce locking required for adding values to enum types (Andrew
        Dunstan, Tom Lane)
       </para>

       <para>
        Previously it was impossible to run <command>ALTER TYPE ... ADD
        VALUE</> in a transaction block unless the enum type was created
        in the same block.  Now, only references to uncommitted enum
        values from other transactions is prohibited.
       </para>
      </listitem>

      <listitem>
<!--
2017-04-07 [c63172d60] Add GUCs for predicate lock promotion thresholds.
-->
       <para>
        Allow tuning of predicate lock promotion thresholds (Dagfinn
        Ilmari Manns&aring;ker)
       </para>

       <para>
        The new settings are <xref
        linkend="guc-max-pred-locks-per-relation"> and
        <xref linkend="guc-max-pred-locks-per-page">.
       </para>
      </listitem>

    </itemizedlist>

    </sect4>

    <sect4>
     <title>Optimizer</title>

     <itemizedlist>

      <listitem>
<!--
2017-03-24 [7b504eb28] Implement multivariate n-distinct coefficients
2017-04-05 [2686ee1b7] Collect and use multi-column dependency stats
-->
      <para>
       Add multi-column optimizer statistics to compute the correlation
       ratio and number of distinct values (Tomas Vondra, David Rowley,
       &Aacute;lvaro Herrera)
      </para>

      <para>
       New commands are <command><link
       linkend="SQL-CREATESTATISTICS">CREATE</></>,
      <command><link linkend="SQL-ALTERSTATISTICS">ALTER</></>, and
      <command><link linkend="SQL-DROPSTATISTICS">DROP STATISTICS</></>.
      This is helpful in
       estimating query memory usage and when combining the statistics
       from individual columns.
      </para>
      </listitem>

      <listitem>
<!--
2017-01-15 [0777f7a2e] Fix matching of boolean index columns to sort ordering.
-->
      <para>
       Improve planner matching of <type>boolean</type> indexes (Tom Lane)
      </para>
      </listitem>

      <listitem>
<!--
2017-01-18 [215b43cdc] Improve RLS planning by marking individual quals with se
-->
      <para>
       Improve performance of queries referencing row-level security
       restrictions (Tom Lane)
      </para>

      <para>
       The optimizer now has more flexibility in reordering executor
       behavior.
      </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>General Performance</title>

     <itemizedlist>

      <listitem>
<!--
2016-09-02 [9cca11c91] Speed up SUM calculation in numeric aggregates.
-->
       <para>
        Speed up <function>SUM()</> calculations (Heikki Linnakangas)
       </para>

       <para>
        This uses an optimized numeric accumulator.
       </para>
      </listitem>

      <listitem>
<!--
2017-03-13 [aeed17d00] Use radix tree for character encoding conversions.
-->
       <para>
        Improve the performance of character encoding conversions by
        using radix trees (Kyotaro Horiguchi, Heikki Linnakangas)
       </para>
      </listitem>

      <listitem>
<!--
2017-03-25 [b8d7f053c] Faster expression evaluation and targetlist projection.
-->
       <para>
        Reduce the function call overhead during query execution (Andres
        Freund)
       </para>

       <para>
        This is particularly helpful for queries that process many rows.
       </para>
      </listitem>

      <listitem>
<!--
2017-03-27 [b5635948a] Support hashed aggregation with grouping sets.
-->
       <para>
        Improve the performance of grouping sets (Andrew Gierth)
       </para>
      </listitem>

      <listitem>
<!--
2017-04-07 [9c7f5229a] Optimize joins when the inner relation can be proven uni
-->
       <para>
        Use uniqueness guarantees to optimize certain join types (David
        Rowley)
       </para>
      </listitem>

      <listitem>
<!--
2017-03-29 [f90d23d0c] Implement SortSupport for macaddr data type
-->
       <para>
        Improve sort performance of the <type>macaddr</type> data type (Brandur Leach)
       </para>
      </listitem>

      <listitem>
<!--
2017-03-27 [090010f2e] Improve performance of find_tabstat_entry()/get_tabstat_
-->
       <para>
        Reduce statistics tracking overhead in sessions that reference
        many thousands of relations (Aleksander Alekseev)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Monitoring</title>

     <itemizedlist>

      <listitem>
<!--
2016-12-20 [1753b1b02] Add pg_sequence system catalog
2016-11-18 [67dc4ccbb] Add pg_sequences view
-->
       <para>
        Create a <link
        linkend="catalog-pg-sequence"><structname>pg_sequence</></>
        system catalog to store sequence metadata (Peter Eisentraut)
       </para>

       <para>
        Sequence metadata includes start, increment, etc,
        which is now transactional.  Sequence counters are
        still stored in separate heap relations.  Also add <link
        linkend="view-pg-sequences"><structname>pg_sequences</></> view
        to show all sequences.
       </para>
      </listitem>

      <listitem>
<!--
2017-03-08 [f9b1a0dd4] Expose explain's SUMMARY option
-->
       <para>
        Allow explicit control over <command><link
        linkend="SQL-EXPLAIN">EXPLAIN</></>'s display of planning and
        execution time (Ashutosh Bapat)
       </para>

       <para>
        By default planning and execution time are displayed by
        <command>EXPLAIN ANALYZE</> and are not displayed in other cases.
        The new <command>EXPLAIN</> option <literal>SUMMARY</> allows
        explicit control of this.
       </para>
      </listitem>

      <listitem>
<!--
2017-03-18 [17f8ffa1e] Fix REFRESH MATERIALIZED VIEW to report activity to the
-->
       <para>
        Properly update the statistics collector during <link
        linkend="SQL-REFRESHMATERIALIZEDVIEW"><command>REFRESH MATERIALIZED
        VIEW</></> (Jim Mlodgenski)
       </para>
      </listitem>

      <listitem>
<!--
2017-03-30 [25fff4079] Default monitoring roles
-->
       <para>
        Add default monitoring roles (Dave Page)
       </para>

       <para>
        New roles <literal>pg_monitor</>, <literal>pg_read_all_settings</>,
        <literal>pg_read_all_stats</>, and <literal>pg_stat_scan_tables</>
        allow simplified permission configuration.
       </para>
      </listitem>

     </itemizedlist>

     <sect5>
      <title>Logging</title>

      <itemizedlist>

       <listitem>
<!--
2016-10-17 [7d3235ba4] By default, set log_line_prefix = '%m [%p] '.
-->
        <para>
         Change <xref linkend="guc-log-line-prefix"> default to include
         current timestamp with milliseconds and the process id (Christoph
         Berg)
        </para>

        <para>
         The previous default was not to output a prefix.
        </para>
       </listitem>

       <listitem>
<!--
2017-03-16 [befd73c50] Add pg_ls_logdir() and pg_ls_waldir() functions.
-->
        <para>
         Add functions to return the log and <acronym>WAL</> directory
         names (Dave Page)
        </para>

        <para>
         The new functions are <link
         linkend="functions-admin-genfile-table"><function>pg_ls_logdir()</></>
         and
        <link
        linkend="functions-admin-genfile-table"><function>pg_ls_waldir()</></>
        and can be
         executed by non-super users with the proper permissions.
        </para>
       </listitem>

       <listitem>
<!--
2017-03-03 [19dc233c3] Add pg_current_logfile() function.
-->
        <para>
         Add function <link
         linkend="functions-info-session-table"><function>pg_current_logfile()</></>
         to read logging collector's current stderr and csvlog output file names
         (Gilles Darold)
        </para>
       </listitem>

       <listitem>
<!--
2017-03-10 [f9dfa5c97] Improve postmaster's logging of listen socket creation.
2017-03-14 [2b32ac2a5] Include port number when logging successful binding to a
-->
        <para>
         Report the address and port number of successful startup socket
         binding in the server logs (Tom Lane)
        </para>

        <para>
         Also, report bind socket failure details in the server logs.
        </para>
       </listitem>

       <listitem>
<!--
2017-03-10 [6ec4c8584] Reduce log verbosity of startup/shutdown for launcher su
-->
        <para>
         Reduce log chatter about the starting and stopping of launcher
         subprocesses (Tom Lane)
        </para>

        <para>
         These are now <literal>DEBUG1</>-level messages.
        </para>
       </listitem>

       <listitem>
<!--
2016-11-17 [a43f1939d] Remove or reduce verbosity of some debug messages.
-->
        <para>
         Reduce message verbosity of lower-numbered debug levels
         controlled by
        <xref linkend="guc-log-min-messages"> (Robert Haas)
        </para>

        <para>
         This also changes the verbosity of <xref
         linkend="guc-client-min-messages"> debug levels.
        </para>
       </listitem>

      </itemizedlist>

     </sect5>

     <sect5>
      <title><link linkend="pg-stat-activity-view"><structname>pg_stat_activity</></link></title>

      <itemizedlist>

       <listitem>
<!--
2016-10-04 [6f3bd98eb] Extend framework from commit 53be0b1ad to report latch w
-->
        <para>
         Add <structname>pg_stat_activity</> reporting of latch wait states
         (Michael Paquier, Robert Haas)
        </para>

        <para>
         This includes the remaining wait events, like client reads,
         client writes, and synchronous replication.
        </para>
       </listitem>

       <listitem>
<!--
2017-03-18 [249cf070e] Create and use wait events for read, write, and fsync op
-->
        <para>
         Add <structname>pg_stat_activity</> reporting of waits on reads,
         writes, and fsyncs (Rushabh Lathia)
        </para>
       </listitem>

       <listitem>
<!--
2017-03-26 [fc70a4b0d] Show more processes in pg_stat_activity.
-->
        <para>
         Show auxiliary processes and background workers in
         <structname>pg_stat_activity</> (Kuntal Ghosh)
        </para>

        <para>
         New column <structfield>backend_type</> identifies the process
         type.
        </para>
       </listitem>

       <listitem>
<!--
2016-09-12 [fc3d4a44e] Identify walsenders in pg_stat_activity
-->
        <para>
         Display walsender processes in <structname>pg_stat_activity</>
         (Michael Paquier)
        </para>

        <para>
         This simplifies monitoring.
        </para>
       </listitem>

       <listitem>
<!--
2017-02-22 [4c728f382] Pass the source text for a parallel query to the workers
-->
        <para>
         Allow <structname>pg_stat_activity</> to show the source query
         being executed by parallel workers (Rafia Sabih)
        </para>
       </listitem>

       <listitem>
<!--
2016-12-16 [3761fe3c2] Simplify LWLock tranche machinery by removing array_base
-->
        <para>
         Rename
         <structname>pg_stat_activity</>.<structfield>wait_event_type</>
         values <literal>LWLockTranche</> and
        <literal>LWLockNamed</> to <literal>LWLock</> (Robert Haas)
        </para>

        <para>
         This makes the output more consistent.
        </para>
       </listitem>

      </itemizedlist>

     </sect5>
    </sect4>

    <sect4>
     <title><acronym>Authentication</></title>

     <itemizedlist>

      <listitem>
<!--
2017-03-07 [818fd4a67] Support SCRAM-SHA-256 authentication (RFC 5802 and 7677)
2017-03-24 [7ac955b34] Allow SCRAM authentication, when pg_hba.conf says 'md5'.
2017-04-07 [60f11b87a] Use SASLprep to normalize passwords for SCRAM authentica
2017-04-18 [c727f120f] Rename "scram" to "scram-sha-256" in pg_hba.conf and pas
-->
       <para>
        Add <link linkend="auth-pg-hba-conf"><literal>SCRAM-SHA-256</></>
        support for password negotiation and storage (Michael Paquier,
        Heikki Linnakangas)
      </para>

       <para>
        This provides better security than the existing <literal>md5</>
        negotiation and storage method.
       </para>
      </listitem>

      <listitem>
<!--
2016-09-28 [babe05bc2] Turn password_encryption GUC into an enum.
-->
       <para>
        Change <acronym>GUC</> <xref linkend="guc-password-encryption">
        from <type>boolean</> to <type>enum</> (Michael Paquier)
       </para>

       <para>
        This was necessary to support additional password hashing options.
       </para>
      </listitem>

      <listitem>
<!--
2017-01-30 [de16ab723] Invent pg_hba_file_rules view to show the content of pg_
-->
       <para>
        Add view <link
        linkend="view-pg-hba-file-rules"><structname>pg_hba_file_rules</></>
        to display the contents of <filename>pg_hba.conf</> (Haribabu
        Kommi)
       </para>

       <para>
        This shows the file contents, not the currently active settings.
       </para>
      </listitem>

      <listitem>
<!--
2017-03-22 [6b76f1bb5] Support multiple RADIUS servers
-->
       <para>
        Support multiple <acronym>RADIUS</> servers (Magnus Hagander)
       </para>

       <para>
        All the <acronym>RADIUS</> related parameters are now plural and
        support a comma-separated list of servers.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Server Configuration</title>

     <itemizedlist>

      <listitem>
<!--
2017-01-02 [de41869b6] Allow SSL configuration to be updated at SIGHUP.
2017-01-03 [1e942c747] Disable prompting for passphrase while (re)loading SSL c
2017-01-04 [6667d9a6d] Re-allow SSL passphrase prompt at server start, but not
-->
       <para>
        Allow <acronym>SSL</> configuration to be updated during
        configuration reload (Andreas Karlsson, Tom Lane)
       </para>

       <para>
        This allows <acronym>SSL</> to be reconfigured without a server
        restart by using <command>pg_ctl reload</>, <command>SELECT
        pg_reload_conf()</>, or sending a <literal>SIGHUP</> signal.
        Reload <acronym>SSL</> configuration updates do not work if the
        <acronym>SSL</> key requires a passphrase.
       </para>
      </listitem>

      <listitem>
<!--
2016-11-30 [81c52728f] doc: Remove claim about large shared_buffers on Windows
-->
       <para>
        Remove documented restriction about using large shared buffers on
       <systemitem class="osname">Windows</> (Takayuki Tsunakawa)
       </para>
      </listitem>

      <listitem>
<!--
2017-03-06 [21d4e2e20] Reduce lock levels for table storage params related to p
2017-04-05 [68ea2b7f9] Reduce lock level for CREATE STATISTICS
-->
       <para>
        Reduce locking required to change table parameters (Simon Riggs,
        Fabr&iacute;zio Mello)
       </para>

       <para>
        For example, changing a table's <xref
        linkend="guc-effective-io-concurrency"> setting can now be done
        with a more lightweight lock.
       </para>
      </listitem>

      <listitem>
<!--
2017-02-02 [14ca9abfb] Increase upper bound for bgwriter_lru_maxpages.
-->
       <para>
        Make the maximum value of <xref
        linkend="guc-bgwriter-lru-maxpages"> effectively unlimited
        (Jim Nasby)
       </para>
      </listitem>

    </itemizedlist>

    </sect4>

    <sect4>
     <title>Reliability</title>

     <itemizedlist>

      <listitem>
<!--
2017-03-27 [1b02be21f] Fsync directory after creating or unlinking file.
-->
       <para>
        Perform an fsync on the directory after creating or unlinking files
        (Michael Paquier)
       </para>

       <para>
        This reduces the risk of data loss after a power failure.
       </para>
      </listitem>

     </itemizedlist>

     <sect5>
      <title><link linkend="wal">Write-Ahead Log</> (<acronym>WAL</>)</title>

      <itemizedlist>

       <listitem>
<!--
2016-12-22 [6ef2eba3f] Skip checkpoints, archiving on idle systems.
-->
        <para>
         Prevent checkpoints and <acronym>WAL</> archiving on
         otherwise-idle systems (Michael Paquier)
        </para>
       </listitem>

       <listitem>
<!--
2017-02-08 [a507b8690] Add WAL consistency checking facility.
2017-03-14 [bb4a39637] hash: Support WAL consistency checking.
-->
        <para>
         Add <acronym>GUC</> <xref linkend="guc-wal-consistency-checking">
         to add details to <acronym>WAL</> that can be sanity-checked on
         the standby (Kuntal Ghosh, Robert Haas)
        </para>

        <para>
         Any sanity-check failure generates a fatal error on the standby.
        </para>
       </listitem>

       <listitem>
<!--
2017-04-05 [00b6b6feb] Allow -\-with-wal-segsize=n up to n=1024MB
-->
        <para>
         Increase the maximum configurable <acronym>WAL</> segment size
         to one gigabyte (Beena Emerson)
        </para>

        <para>
         Larger <acronym>WAL</> segment sizes allows for fewer
         <xref linkend="guc-archive-command"> invocations and fewer
         <acronym>WAL</> files to manage.
        </para>
       </listitem>

      </itemizedlist>

     </sect5>

    </sect4>

   </sect3>

   <sect3>
    <title>Replication and Recovery</title>

    <itemizedlist>

     <listitem>
<!--
2017-01-20 [665d1fad9] Logical replication
2017-03-23 [7c4f52409] Logical replication support for initial data copy
2017-04-12 [ff7bce174] Add max_sync_workers_per_subscription to postgresql.conf
-->
      <para>
       Add the ability to <link linkend="logical-replication">logically
       replicate</> tables to standby servers (Petr Jelinek)
      </para>

      <para>
       This allows more fine-grained replication options, including
       replication between different major versions of PostgreSQL and
       selective-table replication.
      </para>
     </listitem>

     <listitem>
<!--
2016-12-19 [3901fd70c] Support quorum-based synchronous replication.
-->
      <para>
       Allow waiting for commit acknowledgement from standby
       servers irrespective of the order they appear in <xref
       linkend="guc-synchronous-standby-names"> (Masahiko Sawada)
      </para>

      <para>
       Previously the server always waited for the active standbys that
       appeared first in <varname>synchronous_standby_names</>.  The new
       <varname>synchronous_standby_names</> keyword <literal>ANY</> allows
       waiting for any number of standbys irrespective of their ordering.
       This is known as quorum commit.
      </para>
     </listitem>

     <listitem>
<!--
2017-01-14 [f6d6d2920] Change default values for backup and replication paramet
2017-05-02 [34fc61673] Change hot_standby default value to 'on'
-->
      <para>
       Reduce configuration necessary to perform streaming backup and
       replication (Magnus Hagander, Dang Minh Huong)
      </para>

      <para>
       Specifically, defaults were changed for <xref
       linkend="guc-wal-level">, <xref linkend="guc-max-wal-senders">,
       <xref linkend="guc-max-replication-slots">, and <xref
       linkend="guc-hot-standby">.
      </para>
     </listitem>

     <listitem>
<!--
2017-03-09 [be37c2120] Enable replication connections by default in pg_hba.conf
-->
      <para>
       Enable replication from localhost connections by default in
       <link linkend="auth-pg-hba-conf"><filename>pg_hba.conf</></>
       (Michael Paquier)
      </para>

      <para>
       Previously <filename>pg_hba.conf</>'s replication connection
       lines were commented out.  This is particularly useful for
       <application><xref linkend="app-pgbasebackup"></>.
      </para>
     </listitem>

     <listitem>
<!--
2017-03-23 [6912acc04] Replication lag tracking for walsenders
-->
      <para>
       Add columns to <link
       linkend="monitoring-stats-views-table"><structname>pg_stat_replication</></>
       to report replication delay times (Thomas Munro)
      </para>

      <para>
       The new columns are <structfield>write_lag</>,
       <structfield>flush_lag</>, and <structfield>replay_lag</>.
      </para>
     </listitem>

     <listitem>
<!--
2016-09-03 [35250b6ad] New recovery target recovery_target_lsn
-->
      <para>
       Add specification of a Log Sequence Number (<acronym>LSN</>)
       stopping point in
      <link linkend="recovery-config"><filename>recovery.conf</></>
      (Michael Paquier)
      </para>

      <para>
       Previously only specification of the stop name, time, timeline,
       xid, and immediate were supported.
      </para>
     </listitem>

     <listitem>
<!--
2017-03-22 [017e4f258] Expose waitforarchive option through pg_stop_backup()
-->
      <para>
       Allow users to disable <link
       linkend="functions-admin"><function>pg_stop_backup()</></>'s
       waiting for all <acronym>WAL</> to be archived (David Steele)
      </para>

      <para>
       An optional second argument to <function>pg_stop_backup()</>
       controls that behavior.
      </para>
     </listitem>

     <listitem>
<!--
2016-12-12 [a924c327e] Add support for temporary replication slots
-->
      <para>
       Allow creation of <link
       linkend="functions-replication-table">temporary replication slots</>
       (Petr Jelinek)
      </para>

      <para>
       Temporary slots are automatically removed on session exit or error.
      </para>
     </listitem>

     <listitem>
<!--
2017-03-22 [9b013dc23] Improve performance of replay of AccessExclusiveLocks
-->
      <para>
       Improve performance of hot standby replay with better tracking of
       Access Exclusive locks (Simon Riggs, David Rowley)
      </para>
     </listitem>

     <listitem>
<!--
2017-04-04 [728bd991c] Speedup 2PC recovery by skipping two phase state files i
-->
      <para>
       Speed up two-phase commit recovery performance (Stas Kelvich,
       Nikhil Sontakke, Michael Paquier)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Queries</title>

    <itemizedlist>

     <listitem>
<!--
2017-03-08 [fcec6caaf] Support XMLTABLE query expression
-->
      <para>
       Add <link
       linkend="functions-xml-processing-xmltable"><function>XMLTABLE</></>
       function that converts <type>XML</>-formatted data into a row set
       (Pavel Stehule, &Aacute;lvaro Herrera)
      </para>
     </listitem>

     <listitem>
<!--
2016-11-22 [906bfcad7] Improve handling of "UPDATE ... SET (column_list) = row_
-->
      <para>
       Allow <literal>ROW</> to supply values to <command>UPDATE ... SET
       (column_list)</> (Tom Lane)
      </para>

      <para>
       Also allow row values to be supplied by table.*.
      </para>
     </listitem>

     <listitem>
<!--
2016-09-05 [c54159d44] Make locale-dependent regex character classes work for l
-->
      <para>
       Fix regular expression locale class handling for bytes greater
       than <literal>U+7FF</> (Tom Lane)
      </para>

      <para>
       Previously such classes were not recognized.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

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

    <itemizedlist>

     <listitem>
<!--
2016-12-07 [f0e44751d] Implement table partitioning.
-->
      <para>
       Add table <link linkend="SQL-CREATETABLE-PARTITION">partitioning
       syntax</> that automatically creates partition constraints and
       <command>INSERT</> routing (Amit Langote)
      </para>

      <para>
       The syntax supports range and list partitioning.
      </para>
     </listitem>

     <listitem>
<!--
2016-11-04 [8c48375e5] Implement syntax for transition tables in AFTER triggers
2017-04-04 [5ebeb579b] Follow-on cleanup for the transition table patch.
2017-03-31 [597027163] Add transition table support to plpgsql.
-->
      <para>
       Add <link linkend="SQL-CREATETRIGGER"><literal>AFTER</> trigger</>
       transition table to record changed rows (Kevin Grittner)
      </para>

      <para>
       Transition table contents are accessible from server-side languages.
      </para>
     </listitem>

     <listitem>
<!--
2016-12-05 [093129c9d] Add support for restrictive RLS policies
-->
      <para>
       Allow <link linkend="SQL-CREATEPOLICY">restrictive row-level
       security policies</> (Stephen Frost)
      </para>

      <para>
       Previously all security policies were permissive, meaning that any
       matching policy allowed access.  Optional restrictive policies must
       match for access to be granted.  These policy types can be combined.
      </para>
     </listitem>

     <listitem>
<!--
2017-03-28 [ab89e465c] Altering default privileges on schemas
-->
      <para>
       Allow <link linkend="SQL-ALTERDEFAULTPRIVILEGES">default
       permissions</> on schemas (Matheus Oliveira)
      </para>

      <para>
       This is done using the <literal>ALTER DEFAULT PRIVILEGES</> command.
      </para>
     </listitem>

     <listitem>
<!--
2017-02-10 [2ea5b06c7] Add CREATE SEQUENCE AS <data type> clause
-->
      <para>
       Add <link linkend="SQL-CREATESEQUENCE"><command>CREATE SEQUENCE
       AS</></> command to create a sequence matching an integer data type
       (Peter Eisentraut)
      </para>

      <para>
       This simplifies the creation of sequences matching the range of
       base columns.
      </para>
     </listitem>

     <listitem>
<!--
2016-11-10 [279c439c7] Support "COPY view FROM" for views with INSTEAD OF INSER
-->
      <para>
       Allow <command>COPY view FROM</> on views with <literal>INSTEAD
       INSERT</> triggers (Haribabu Kommi)
      </para>

      <para>
       The triggers are fed the rows from <command>COPY</>.
      </para>
     </listitem>

     <listitem>
<!--
2017-03-14 [aefeb6874] Allow referring to functions without arguments when uniq
-->
      <para>
       Allow the specification of a function name without arguments in
       <acronym>DDL</> commands, when unique (Peter Eisentraut)
      </para>

      <para>
       For example, allow <link linkend="SQL-DROPFUNCTION"><command>DROP
       FUNCTION</></> on a function name without arguments if there
       is only one function with that name.  This is required by the
       <acronym>SQL</> standard.
      </para>
     </listitem>

     <listitem>
<!--
2017-03-06 [583f6c414] Allow dropping multiple functions at once
-->
      <para>
       Allow multiple functions, operators, and aggregates to be dropped
       with a single <command>DROP</> command (Peter Eisentraut)
      </para>
     </listitem>

     <listitem>
<!--
2017-03-20 [b6fb534f1] Add IF NOT EXISTS for CREATE SERVER and CREATE USER MAPP
-->
      <para>
       Add <literal>IF NOT EXISTS</> for <link
       linkend="SQL-CREATESERVER"><command>CREATE SERVER</></> and
      <link linkend="SQL-CREATEUSERMAPPING"><command>CREATE USER
      MAPPING</></> (Anastasia
       Lubennikova)
      </para>
     </listitem>

     <listitem>
<!--
2017-02-15 [6d16ecc64] Add CREATE COLLATION IF NOT EXISTS clause
-->
      <para>
       Add <literal>IF NOT EXISTS</> clause to <link
       linkend="SQL-CREATECOLLATION"><command>CREATE COLLATION</></>
       (Peter Eisentraut)
      </para>
     </listitem>

     <listitem>
<!--
2017-03-25 [70adf2fbe] Make VACUUM VERBOSE report the number of skipped frozen
2017-03-03 [9eb344faf] Allow vacuums to report oldestxmin
-->
      <para>
       Have <link linkend="SQL-VACUUM"><command>VACUUM VERBOSE</></> report
       the number of skipped frozen pages and oldest xmin (Masahiko
       Sawada, Simon Riggs)
      </para>

      <para>
       This information is also included in <xref
       linkend="guc-log-autovacuum-min-duration"> output.
      </para>
     </listitem>

     <listitem>
<!--
2017-01-23 [7e26e02ee] Prefetch blocks during lazy vacuum's truncation scan
-->
      <para>
       Improve speed of <command>VACUUM</>'s removal of trailing empty
       heap pages (Claudio Freire, &Aacute;lvaro Herrera)
      </para>

      <para>
       This information is also included in <xref
       linkend="guc-log-autovacuum-min-duration"> output.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

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

    <itemizedlist>

      <listitem>
<!--
2017-03-31 [e306df7f9] Full Text Search support for JSON and JSONB
-->
       <para>
        Add full text search support for <type>JSON</> and <type>JSONB</>
        (Dmitry Dolgov)
       </para>

       <para>
        This is accessed via <function>ts_headline()</> and
        <function>to_tsvector</>.
       </para>
      </listitem>

     <listitem>
<!--
2017-03-15 [c7a9fa399] Add support for EUI-64 MAC addresses as macaddr8
-->
      <para>
       Add support for <acronym>EUI-64</> <acronym>MAC</> addresses as
       <link linkend="datatype-macaddr8"><type>MACADDR8</></> (Haribabu
       Kommi)
      </para>

      <para>
       This complements support for <acronym>EUI-48</> <acronym>MAC</>
       addresses as <type>macaddr</>.
      </para>
     </listitem>

     <listitem>
<!--
2017-04-06 [321732705] Identity columns
-->
      <para>
       Add <link linkend="SQL-CREATETABLE">identity columns</> for
       assigning a numeric value to columns on insert (Peter Eisentraut)
      </para>

      <para>
       These are similar to <type>SERIAL</> columns, but are
       <acronym>SQL</> standard compliant.
      </para>
     </listitem>

     <listitem>
<!--
2016-09-07 [0ab9c56d0] Support renaming an existing value of an enum type.
-->
      <para>
       Allow <link linkend="datatype-enum"><type>ENUM</></> values to be
       renamed (Dagfinn Ilmari Manns&aring;ker)
      </para>

      <para>
       This uses the syntax <link linkend="SQL-ALTERTYPE"><command>ALTER
       TYPE ... RENAME VALUE</></>.
      </para>
     </listitem>

     <listitem>
<!--
2017-02-22 [502a3832c] Correctly handle array pseudotypes in to_json and to_jso
-->
      <para>
       Properly treat array pseudotypes
       (<type>anyarray</>) as arrays in <link
       linkend="functions-json-creation-table"><function>to_json()</></>
       and <function>to_jsonb()</> (Andrew Dunstan)
      </para>

      <para>
       Previously "anyarray" values were converted to <type>JSON</>
       strings.
      </para>
     </listitem>

     <listitem>
<!--
2017-01-17 [323b96aa3] Register missing money operators in system catalogs
-->
      <para>
       Add operators for multiplication and division
       of <link linkend="datatype-money"><type>money</></link> values
       with <type>int8</> values (Peter Eisentraut)
      </para>

      <para>
       Previously such cases would result in converting the <type>int8</>
       values to <type>float8</> and then using
       the <type>money</>-and-<type>float8</> operators.  The new behavior
       avoids possible precision loss.  But note that division
       of <type>money</> by <type>int8</> now truncates the quotient, like
       other integer-division cases, while the previous behavior would have
       rounded.
      </para>
     </listitem>

     <listitem>
<!--
2016-09-14 [656df624c] Add overflow checks to money type input function
-->
      <para>
       More strictly check the <type>money</> type for overflow operations
       (Peter Eisentraut)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Functions</title>

    <itemizedlist>

     <listitem>
<!--
2016-08-17 [cf9b0fea5] Implement regexp_match(), a simplified alternative to re
-->
      <para>
       Add simplified <link
       linkend="functions-posix-regexp"><function>regexp_match()</></>
       function (Emre Hasegeli)
      </para>

      <para>
       Similar to <function>regexp_matches()</>, but only returns results
       from the first match so it is easier use for simple cases.
      </para>
     </listitem>

     <listitem>
<!--
2017-01-18 [d00ca333c] Implement array version of jsonb_delete and operator
-->
      <para>
       Add version of jsonb's <link
       linkend="functions-jsonb-op-table">delete operator</> that takes
       an array of keys to delete (Magnus Hagander)
      </para>

      <para>
       The <type>JSONB</> delete operator also now supports arrays.
      </para>
     </listitem>

     <listitem>
<!--
2017-04-06 [cf35346e8] Make json_populate_record and friends operate recursivel
-->
      <para>
       Improve <link
       linkend="functions-json-processing-table"><function>json_populate_record</></>
       and friends operate recursively (Nikita Glukhov)
      </para>

      <para>
       CLARIFY
      </para>
     </listitem>

     <listitem>
<!--
2016-08-23 [86f31695f] Add txid_current_ifassigned().
-->
      <para>
       Add function <link
       linkend="functions-txid-snapshot"><function>txid_current_ifassigned()</></>
       to return <literal>NULL</> if no transaction id has been assigned
       (Craig Ringer)
      </para>

      <para>
       This is different from <link
       linkend="functions-txid-snapshot"><function>txid_current()</></>,
       which always returns a transaction id by assigning one if necessary.
       This can be also run on standby servers.
      </para>
     </listitem>

     <listitem>
<!--
2017-03-24 [857ee8e39] Add a txid_status function.
-->
      <para>
       Add function <link
       linkend="functions-txid-snapshot"><function>txid_status()</></>
       to check if a transaction was committed (Craig Ringer)
      </para>

      <para>
       This is useful for checking after an abrupt disconnection if
       your previous transaction committed and you just didn't receive
       the acknowledgement.
      </para>
     </listitem>

     <listitem>
<!--
2017-01-19 [30bcebbdc] Allow negative years in make_date to represent BC years
-->
      <para>
       Allow <link
       linkend="functions-formatting-table"><function>make_date()</></>
       to interpret negative years as <acronym>BC</> years (&Aacute;lvaro
       Herrera)
      </para>
     </listitem>

     <listitem>
<!--
2016-09-28 [d3cd36a13] Make to_timestamp() and to_date() range-check fields of
-->
      <para>
       Have <function>to_timestamp()</> and <function>to_date()</> check
       input values for validity (Artur Zakirov)
      </para>

      <para>
       Previously <function>to_date('2009-06-40','YYYY-MM-DD')</> was
       accepted and returned '2009-07-10'.  It will now generate an error.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

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

    <itemizedlist>

     <listitem>
<!--
2017-03-27 [70ec3f1f8] PL/Python: Add cursor and execute methods to plan object
-->
      <para>
       Allow the  PL/Python plan object to call cursor and execute methods
       (Peter Eisentraut)
      </para>

      <para>
       This is a more object oriented style.
      </para>
     </listitem>

     <listitem>
<!--
2016-12-13 [55caaaeba] Improve handling of array elements as getdiag_targets an
-->
      <para>
       Allow PL/pgSQL's <command>GET DIAGNOSTICS</> to retrieve values
       into array elements (Tom Lane)
      </para>
     </listitem>

     <listitem>
<!--
2016-11-08 [1833f1a1c] Simplify code by getting rid of SPI_push, SPI_pop, SPI_r
-->
      <para>
       Remove <acronym>SPI</> functions <function>SPI_push()</>,
       <function>SPI_pop()</>, <function>SPI_restore_connection()</>
       as unnecessary (Tom Lane)
      </para>

      <para>
       Their functionality now happens automatically.  Also,
       <function>SPI_palloc()</> now requires an active connection.
      </para>
     </listitem>

    </itemizedlist>

    <sect4>
     <title><link linkend="pltcl">PL/Tcl</></title>

     <itemizedlist>

      <listitem>
<!--
2016-11-06 [26abb50c4] Support PL/Tcl functions that return composite types and
-->
       <para>
        Allow PL/Tcl functions to return composite types and sets
        (Jim Nasby)
       </para>
      </listitem>

      <listitem>
<!--
2017-03-11 [b58fd4a9c] Add a "subtransaction" command to PL/Tcl.
-->
       <para>
        Add a subtransaction command to PL/Tcl (Victor Wagner)
       </para>

       <para>
        This allows PL/Tcl queries to fail without aborting the entire
        function.
       </para>
      </listitem>

      <listitem>
<!--
2017-03-07 [0d2b1f305] Invent start_proc parameters for PL/Tcl.
-->
       <para>
        Add <acronym>GUC</>s to allow initialization routines to be called
        on PL/Tcl startup (Tom Lane)
       </para>

       <para>
        The <acronym>GUC</>s are <varname>pltcl.start_proc</> and
        <varname>pltclu.start_proc</>.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>
   </sect3>

   <sect3>
    <title>Client Interfaces</title>

    <itemizedlist>

     <listitem>
<!--
2016-11-03 [274bb2b38] libpq: Allow connection strings and URIs to specify mult
-->
      <para>
       Allow libpq to connect to <link
       linkend="libpq-connect-host">multiple specified</> host names
       (Robert Haas)
      </para>

      <para>
       libpq will connect with the first responsive host name.
      </para>
     </listitem>

     <listitem>
<!--
2016-11-29 [721f7bd3c] libpq: Add target_session_attrs parameter.
-->
      <para>
       Allow the libpq connection string to request a <link
       linkend="libpq-connect-target-session-attrs">read/write host</>
       (Victor Wagner, Mithun Cy)
      </para>

      <para>
       This is useful when multiple libpq host names are
       specified, and is controlled by libpq connection parameter
       <option>target_session_attrs</>.
      </para>
     </listitem>

     <listitem>
<!--
2017-01-24 [ba005f193] Allow password file name to be specified as a libpq conn
-->
      <para>
       Allow <link linkend="libpq-connect-passfile">password file name</>
       to be specified as a libpq connection parameter (Julian Markwort)
      </para>

      <para>
       Previously this could only be specified via an environment variable.
      </para>
     </listitem>

     <listitem>
<!--
2017-05-03 [8f8b9be51] Add PQencryptPasswordConn function to libpq, use it in p
-->
      <para>
       Add function <link
       linkend="libpq-pqencryptpasswordconn"><function>PQencryptPasswordConn()</></>
       to allow creation of more types of encrypted passwords on the
       client-side (Michael Paquier, Heikki Linnakangas)
      </para>

      <para>
       Previously only <literal>MD5</> passwords could be created using <link
       linkend="libpq-pqencryptpassword"><function>PQencryptPassword()</></>.
       This new function can also create <link
       linkend="auth-pg-hba-conf"><literal>SCRAM-SHA-256</></> passwords.
      </para>
     </listitem>

     <listitem>
<!--
2016-08-16 [a7b5573d6] Remove separate version numbering for ecpg preprocessor.
-->
      <para>
       ecpg preprocessor version changed from 4.12 to 10 (Tom Lane)
      </para>

      <para>
       The ecpg version now matches the PostgreSQL distribution version
       number.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Client Applications</title>

    <sect4>
     <title><xref linkend="APP-PSQL"></title>

     <itemizedlist>

      <listitem>
<!--
2017-03-30 [e984ef586] Support \if ... \elif ... \else ... \endif in psql scrip
2017-04-02 [5dbc5da11] Fix behavior of psql's \p to agree with \g, \w, etc.
2017-04-02 [68dba97a4] Document psql's behavior of recalling the previously exe
-->
       <para>
        Add conditional branch support to <application>psql</> (Corey
        Huinker)
       </para>

       <para>
        The new syntax uses \if, \elif, \else, and \endif.  This is
        particularly helpful for scripting.
       </para>
      </listitem>

      <listitem>
<!--
2017-03-07 [b2678efd4] psql: Add \gx command
-->
       <para>
        Add <application>psql</> \gx command to perform \g(execute)
        in expanded mode (\x) (Christoph Berg)
       </para>
      </listitem>

      <listitem>
<!--
2016-11-03 [a0f357e57] psql: Split up "Modifiers" column in \d and \dD
-->
       <para>
        Improve <application>psql</>'s \d (relation) and \dD (domain)
        commands to specify collation, nullable, and default in separate
        columns (Peter Eisentraut)
       </para>

       <para>
        Previous they were in a single "Modifiers" column.
       </para>
      </listitem>

      <listitem>
<!--
2017-04-01 [f833c847b] Allow psql variable substitution to occur in backtick co
-->
       <para>
        Expand <application>psql</> colon variables when used in
        backtick-executed contexts (Tom Lane)
       </para>

       <para>
        This is particularly useful for the new <application>psql</>
        conditional branch support commands.
       </para>
      </listitem>

      <listitem>
<!--
2017-01-30 [511ae628f] Make psql reject attempts to set special variables to in
2017-02-01 [86322dc7e] Improve psql's behavior for \set and \unset of its contr
2017-02-02 [fd6cd6980] Clean up psql's behavior for a few more control variable
-->
       <para>
        Prevent <application>psql</> special variables from being set to
        invalid values (Daniel V&eacute;rit&eacute;, Tom Lane)
       </para>

       <para>
        Previously setting <application>psql</> special variables
        to invalid values produced the default behavior.  \set and
        \unset of special variables now sets them to "on" and its
        default value, rather than a zero-length string and undefined.
        Also have \set always display values for <literal>FETCH_COUNT</>,
        <literal>HISTSIZE</>, and <literal>IGNOREEOF</>.
       </para>
      </listitem>

      <listitem>
<!--
2016-08-18 [49917dbd7] Improve psql's tab completion for ALTER EXTENSION foo UP
2016-08-18 [8019b5a89] Improve psql's tab completion for \l.
2016-09-01 [76f9dd4fa] Improve tab completion for BEGIN & START|SET TRANSACTION
2016-09-11 [52803098a] psql tab completion for CREATE DATABASE ... TEMPLATE ...
2016-09-12 [63c1a8719] Fix recent commit for tab-completion of database templat
2016-11-03 [1d15d0db5] psql: Tab-complete LOCK [TABLE] ... IN {ACCESS|ROW|SHARE
2016-11-04 [927d7bb6b] Improve tab completion for CREATE TRIGGER.
2016-11-08 [577f0bdd2] psql: Tab completion for renaming enum values.
2017-03-01 [b5a388392] psql: Add tab completion for DEALLOCATE
2017-03-16 [d7d77f382] psql: Add completion for \help DROP|ALTER
-->
       <para>
        Improve <application>psql</>'s tab completion (Jeff Janes,
        Ian Barwick, Andreas Karlsson, Sehrope Sarkuni, Thomas Munro,
        Kevin Grittner, Dagfinn Ilmari Manns&aring;ker)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title><xref linkend="pgbench"></title>

     <itemizedlist>

      <listitem>
<!--
2016-11-09 [41124a91e] pgbench: Allow the transaction log file prefix to be cha
-->
       <para>
        Add pgbench option <option>--log-prefix</> to control the log
        file prefix (Masahiko Sawada)
       </para>
      </listitem>

      <listitem>
<!--
2017-01-20 [cdc2a7047] Allow backslash line continuations in pgbench's meta com
-->
       <para>
        Allow pgbench's meta commands to span multiple lines via a
        line-terminating backslash (Fabien Coelho)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

   <sect3>
    <title>Server Applications</title>

    <itemizedlist>

     <listitem>
<!--
2017-01-17 [cada1af31] Add compression support to pg_receivexlog
-->
      <para>
       Add <link
       linkend="app-pgreceivewal"><application>pg_receivewal</></>
       option <option>-Z</>/<option>--compress</> to support compression
       (Michael Paquier)
      </para>
     </listitem>

     <listitem>
<!--
2017-01-04 [7c030783a] Add pg_recvlogical -\-endpos=LSN
-->
      <para>
       Add <link
       linkend="app-pgrecvlogical"><application>pg_recvlogical</></> option
       (<option>--endpos</>) to specify the ending position (Craig Ringer)
      </para>

      <para>
       This complements the existing <option>--startpos</> option.
      </para>
     </listitem>

     <listitem>
<!--
2016-10-19 [5d58c07a4] initdb pg_basebackup: Rename -\-noxxx options to -\-no-x
-->
      <para>
       Rename <link linkend="APP-INITDB"><application>initdb</></>
       options <option>--noclean</> and <option>--nosync</> to be spelled
       <option>--no-clean</> and <option>--no-sync</> (Vik Fearing,
       Peter Eisentraut)
      </para>

      <para>
       The old spellings are still supported.
      </para>
     </listitem>

    </itemizedlist>

    <sect4>
     <title><link linkend="APP-PGDUMP"><application>pg_dump</></>, <link linkend="APP-PG-DUMPALL"><application>pg_dumpall</></>.
     <link linkend="APP-PGRESTORE"><application>pg_restore</></></title>

     <itemizedlist>

      <listitem>
<!--
2016-09-20 [46b55e7f8] pg_restore: Add -N option to exclude schemas
-->
       <para>
        Allow <application>pg_restore</> to exclude schemas (Michael Banck)
       </para>

       <para>
        This added a new <option>-N</>/<option>--exclude-schema</> option.
       </para>
      </listitem>

      <listitem>
<!--
2016-11-29 [4fafa579b] Add -\-no-blobs option to pg_dump
-->
       <para>
        Add <option>--no-blobs</> option to
       <application>pg_dump</> (Guillaume Lelarge)
       </para>

       <para>
        This suppresses the dumping of large objects.
       </para>
      </listitem>

      <listitem>
<!--
2017-03-07 [9a83d56b3] Allow pg_dumpall to dump roles w/o user passwords
-->
       <para>
        Add <application>pg_dumpall</> option
        <option>--no-role-passwords</> to dump roles without user passwords
        (Robins Tharakan, Simon Riggs)
       </para>

       <para>
        This allows easier dumping for less-privileged users.
       </para>
      </listitem>

      <listitem>
<!--
2017-03-22 [96a7128b7] Sync pg_dump and pg_dumpall output
-->
       <para>
        Issue fsync on the output files generated by
        <application>pg_dump</> and
       <application>pg_dumpall</> (Michael Paquier)
       </para>

       <para>
        This can be disabled with the <option>--no-sync</> option.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>

    <title><xref linkend="app-pgbasebackup"></title>

     <itemizedlist>

      <listitem>
<!--
2016-10-23 [56c7d8d45] Allow pg_basebackup to stream transaction log in tar mod
2016-12-21 [ecbdc4c55] Forbid invalid combination of options in pg_basebackup.
-->
       <para>
        Allow <application>pg_basebackup</> to stream write-ahead log in
        tar mode (Magnus Hagander)
       </para>

       <para>
        The <acronym>WAL</> will be stored in a separate tar file from
        the base backup.
       </para>
      </listitem>

      <listitem>
<!--
2017-01-16 [e7b020f78] Make pg_basebackup use temporary replication slots
-->
       <para>
        Make <application>pg_basebackup</> use temporary replication slots
        (Magnus Hagander)
       </para>

       <para>
        Temporary replication slots will be used by default when
        <application>pg_basebackup</> uses WAL streaming with default
        options.
       </para>
      </listitem>

      <listitem>
<!--
2016-09-29 [bc34223bc] pg_basebackup pg_receivexlog: Issue fsync more carefully
2016-09-29 [6ed2d8584] pg_basebackup: Add - option
-->
       <para>
        Improve fsync handling of <application>pg_basebackup</> and
        <application>pg_receivewal</> (Michael Paquier)
       </para>

       <para>
        Also add <option>--nosync</> option to disable fsync.
       </para>
      </listitem>

      <listitem>
<!--
2016-09-28 [6ad8ac602] Exclude additional directories in pg_basebackup
-->
       <para>
        Improve <application>pg_basebackup</>'s handling of which
        directories to skip (David Steele)
       </para>

       <para>
        Also improve the documentation of skipped directories.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title><application><xref linkend="app-pg-ctl"></></title>

     <itemizedlist>

      <listitem>
<!--
2016-09-21 [e7010ce47] pg_ctl: Add wait option to promote action
-->
       <para>
        Add wait option for <application><xref linkend="app-pg-ctl"></>'s
        promote operation (Peter Eisentraut)
       </para>
      </listitem>

      <listitem>
<!--
2016-10-19 [0be22457d] pg_ctl: Add long options for -w and -W
-->
       <para>
        Add long options for <application>pg_ctl</> wait (<option>--wait</>)
        and no-wait (<option>--no-wait</>) (Vik Fearing)
       </para>
      </listitem>

      <listitem>
<!--
2016-10-19 [caf936b09] pg_ctl: Add long option for -o
-->
       <para>
        Add long options flag for <application>pg_ctl</>
        <literal>options</> (Peter Eisentraut)
       </para>

       <para>
        It is called <option>--options</>.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>
   </sect3>

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

    <itemizedlist>

     <listitem>
<!--
2016-08-15 [ca9112a42] Stamp HEAD as 10devel.
-->
      <para>
       New major version numbering (Peter Eisentraut, Tom Lane)
      </para>

      <para>
       Major versions will now increase just the first number, and minor
       releases will increase just the second number.  A third number
       will no longer be used in PostgreSQL version numbers.
      </para>
     </listitem>

     <listitem>
<!--
2017-03-23 [eccfef81e] ICU support
-->
      <para>
       Allow the <link linkend="configure"><acronym>ICU</></> library to
       optionally be used for collation support (Peter Eisentraut)
      </para>

      <para>
       The <acronym>ICU</> library has versioning that allows detection
       of collation changes between versions.  It is enabled via configure
       option <option>--with-icu</>.  The default still uses the operating
       system's native collation library.
      </para>
     </listitem>

     <listitem>
<!--
2016-11-04 [c8ead2a39] Provide DLLEXPORT markers for C functions via PG_FUNCTIO
-->
      <para>
       Automatically mark all <link
       linkend="xfunc-c"><function>PG_FUNCTION_INFO_V1</></> functions
       as <literal>DLLEXPORT</>-ed on
      <systemitem class="osname">Windows</> (Laurenz Albe)
      </para>

      <para>
       If third-party code is using <literal>extern</> function
       declarations, they should also add <literal>DLLEXPORT</> markers
       to those declarations.
      </para>
     </listitem>

     <listitem>
<!--
2016-12-02 [13e14a78e] Management of free memory pages.
2016-12-02 [13df76a53] Introduce dynamic shared memory areas.
2016-12-19 [e13029a5c] Provide a DSA area for all parallel queries.
-->
      <para>
       Allow shared memory to be dynamically allocated (Thomas Munro,
       Robert Haas)
      </para>
     </listitem>

     <listitem>
<!--
2017-02-27 [58b25e981] Add "Slab" MemoryContext implementation for efficient eq
-->
      <para>
       Add slab-like memory allocator for efficient fixed-size allocations
       (Tomas Vondra)
      </para>
     </listitem>

     <listitem>
<!--
2016-10-09 [ecb0d20a9] Use unnamed POSIX semaphores, if available, on Linux and
-->
      <para>
       Use <acronym>POSIX</> semaphores rather than SysV semaphores
       on <systemitem class="osname">Linux</> and <systemitem
       class="osname">FreeBSD</> (Tom Lane)
      </para>

      <para>
       This avoids some limits on SysV semaphore usage.
      </para>
     </listitem>

     <listitem>
<!--
2017-04-07 [e8fdbd58f] Improve 64bit atomics support.
-->
      <para>
       Improve support for 64-bit atomics (Andres Freund)
      </para>
     </listitem>

     <listitem>
<!--
2017-03-10 [f8f1430ae] Enable 64 bit atomics on ARM64.
-->
      <para>
       Enable 64-bit atomic operations on <acronym>ARM64</> (Roman
       Shaposhnik)
      </para>
     </listitem>

     <listitem>
<!--
2017-01-02 [1d63f7d2d] Use clock_gettime(), if available, in instr_time measure
-->
      <para>
       Switch to using <function>clock_gettime()</>, if available, for
       duration measurements (Tom Lane)
      </para>

      <para>
      <function>gettimeofday()</> is used if <function>clock_gettime()</>
      is not available.
      </para>
     </listitem>

     <listitem>
<!--
2016-12-05 [fe0a0b599] Replace PostmasterRandom() with a stronger source, secon
-->
      <para>
       Add more robust random number generators to be used for
       cryptographic secure uses (Magnus Hagander, Michael Paquier,
       Heikki Linnakangas)
      </para>

      <para>
       If no strong random number generator can be found, configure
       will fail unless the <link linkend="configure">configure</>
       <option>--disable-strong-random</> is used.  However, with this
       option, pgcrypto functions requiring a strong random number
       generator will be disabled.
      </para>
     </listitem>

     <listitem>
<!--
2016-08-18 [e8306745e] doc: Speed up XSLT builds
2016-08-24 [0e4cc1fc5] doc: Fix XSLT speedup with older upstream stylesheet ver
-->
      <para>
       Overhaul documentation <link linkend="docguide-toolsets">build
       process</> (Alexander Lakhin, Alexander Law)
      </para>
     </listitem>

     <listitem>
<!--
2017-04-06 [510074f9f] Remove use of Jade and DSSSL
-->
      <para>
       Use <acronym>XSLT</> to build the PostgreSQL documentation (Peter
       Eisentraut)
      </para>

      <para>
       Previously <application>Jade</>, <acronym>DSSSL,</> and
       <application>JadeTex</> were used.
      </para>
     </listitem>

     <listitem>
<!--
2016-11-15 [e36ddab11] Build HTML documentation using XSLT stylesheets by defau
-->
      <para>
       Build <acronym>HTML</> documentation using <acronym>XSLT</>
       stylesheets by default (Peter Eisentraut)
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Additional Modules</title>

    <itemizedlist>

     <listitem>
<!--
2016-09-29 [8e91e12bc] Allow contrib/file_fdw to read from a program, like COPY
-->
      <para>
       Allow <link linkend="file-fdw"><application>file_fdw</></> to read
       from program output as well as files (Corey Huinker, Adam Gomaa)
      </para>
     </listitem>

     <listitem>
<!--
2016-10-21 [7012b132d] postgres_fdw: Push down aggregates to remote servers.
2017-04-24 [332bec1e6] postgres_fdw: Fix join push down with extensions
-->
      <para>
       Push aggregates to foreign data wrapper servers, where possible
       (Jeevan Chalke, Ashutosh Bapat)
      </para>

      <para>
       This reduces the amount of data that must be passed
       from the foreign data wrapper server, and offloads
       aggregate computation from the requesting server.  The <link
       linkend="postgres-fdw"><application>postgres_fdw</></> is able to
       perform this optimization.  There are also improvements in
       pushing down joins involving extensions.
      </para>
     </listitem>

     <listitem>
<!--
2017-03-16 [b30fb56b0] postgres_fdw: Push down FULL JOINs with restriction clau
-->
      <para>
       Allow push down of <literal>FULL JOIN</> queries containing
       subqueries in the
      <literal>FROM</> clause to foreign servers (Etsuro Fujita)
      </para>
     </listitem>

     <listitem>
<!--
2016-08-26 [ae025a159] Support OID system column in postgres_fdw.
-->
      <para>
       Properly support <type>OID</> columns in
       <application>postgres_fdw</> tables (Etsuro Fujita)
      </para>

      <para>
       Previously <type>OID</> columns always returned zeros.
      </para>
     </listitem>

     <listitem>
<!--
2017-03-21 [f7946a92b] Add btree_gist support for enum types.
-->
      <para>
       Allow <link linkend="btree-gist"><application>btree_gist</></>
       and <link linkend="btree-gin"><application>btree_gin</></> to
       index enum types (Andrew Dunstan)
      </para>

      <para>
       This allows enums to be used in exclusion constraints.
      </para>
     </listitem>

     <listitem>
<!--
2016-11-29 [11da83a0e] Add uuid to the set of types supported by contrib/btree_
-->
      <para>
       Add indexing support to <application>btree_gist</> for the
       <type>UUID</> data type (Paul Jungwirth)
      </para>
     </listitem>

     <listitem>
<!--
2017-03-09 [3717dc149] Add amcheck extension to contrib.
-->
      <para>
       Add <link linkend="amcheck"><application>amcheck</></> which can
       check the validity of B-tree indexes (Peter Geoghegan)
      </para>
     </listitem>

     <listitem>
<!--
2017-03-27 [a6f22e835] Show ignored constants as "$N" rather than "?" in pg_sta
-->
      <para>
       Show ignored constants as <literal>$N</> rather than <literal>?</>
       in
      <link
      linkend="pgstatstatements"><application>pg_stat_statements</></>
      (Lukas Fittl)
      </para>
     </listitem>

     <listitem>
<!--
2016-09-27 [f31a931fa] Improve contrib/cube's handling of zero-D cubes, infinit
-->
      <para>
       Improve <link linkend="cube"><application>cube</></>'s handling
       of zero-dimensional cubes (Tom Lane)
      </para>

      <para>
       This also improves handling of <literal>infinite</> and
       <literal>NaN</> values.
      </para>
     </listitem>

     <listitem>
<!--
2016-09-29 [6e654546f] Don't bother to lock bufmgr partitions in pg_buffercache
-->
      <para>
       Allow <link
       linkend="pgbuffercache"><application>pg_buffercache</></> to run
       with fewer locks (Ivan Kartyshov)
      </para>

      <para>
       This allows it be less disruptive when run on production systems.
      </para>
     </listitem>

     <listitem>
<!--
2017-02-03 [e759854a0] pgstattuple: Add pgstathashindex.
-->
      <para>
       Add <function>pgstathashindex()</> function to <link
       linkend="pgstattuple"><application>pgstattuple</></> to view hash
       index statistics (Ashutosh Sharma)
      </para>
     </listitem>

     <listitem>
<!--
2016-09-29 [fd321a1df] Remove superuser checks in pgstattuple
-->
      <para>
       Allow <link linkend="pgstattuple"><application>pgstattuple</></>
       to use <command>GRANT</> permissions (Stephen Frost)
      </para>

      <para>
       This allows non-superusers to run these functions if permissions
       allow.
      </para>
     </listitem>

     <listitem>
<!--
2016-10-28 [d4b5d4cad] pgstattuple: Don't take heavyweight locks when examining
-->
      <para>
       Reduce locking when <link
       linkend="pgstattuple"><application>pgstattuple</></> examines hash
       indexes (Amit Kapila)
      </para>
     </listitem>

     <listitem>
<!--
2017-03-17 [fef2bcdcb] pageinspect: Add page_checksum function
-->
      <para>
       Add <function>page_checksum()</> function to <link
       linkend="pageinspect"><application>pageinspect</></> (Tomas Vondra)
      </para>
     </listitem>

     <listitem>
<!--
2017-02-02 [08bf6e529] pageinspect: Support hash indexes.
-->
      <para>
       Add hash index support to <link
       linkend="pageinspect"><application>pageinspect</></> (Jesper
       Pedersen, Ashutosh Sharma)
      </para>
     </listitem>

     <listitem>
<!--
2017-04-04 [193f5f9e9] pageinspect: Add bt_page_items function with bytea argum
-->
      <para>
       Add <link linkend="pageinspect"><application>pageinspect</></>
       function <function>bt_page_items()</> to print page items from a
       page image (Tomas Vondra)
      </para>

      <para>
       Previously only block numbers were supported.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

  </sect2>

 </sect1>
