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 <sect1 id="release-9-5-1">
  <title>Release 9.5.1</title>

  <note>
  <title>Release Date</title>
  <simpara>2016-02-11</simpara>
  </note>

  <para>
   This release contains a variety of fixes from 9.5.0.
   For information about new features in the 9.5 major release, see
   <xref linkend="release-9-5">.
  </para>

  <sect2>
   <title>Migration to Version 9.5.1</title>

   <para>
    A dump/restore is not required for those running 9.5.X.
   </para>
  </sect2>

  <sect2>
   <title>Changes</title>

   <itemizedlist>

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    <listitem>
     <para>
      Fix infinite loops and buffer-overrun problems in regular expressions
      (Tom Lane)
     </para>

     <para>
      Very large character ranges in bracket expressions could cause
      infinite loops in some cases, and memory overwrites in other cases.
      (CVE-2016-0773)
     </para>
    </listitem>

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    <listitem>
     <para>
      Fix an oversight that caused hash joins to miss joining to some tuples
      of the inner relation in rare cases (Tomas Vondra, Tom Lane)
     </para>
    </listitem>

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    <listitem>
     <para>
      Avoid pushdown of <literal>HAVING</> clauses when grouping sets are
      used (Andrew Gierth)
     </para>
    </listitem>

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    <listitem>
     <para>
      Fix deparsing of <literal>ON CONFLICT</> arbiter <literal>WHERE</>
      clauses (Peter Geoghegan)
     </para>
    </listitem>

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    <listitem>
     <para>
      Make <literal>%h</> and <literal>%r</> escapes
      in <varname>log_line_prefix</> work for messages emitted due
      to <varname>log_connections</> (Tom Lane)
     </para>

     <para>
      Previously, <literal>%h</>/<literal>%r</> started to work just after a
      new session had emitted the <quote>connection received</> log message;
      now they work for that message too.
     </para>
    </listitem>

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    <listitem>
     <para>
      Avoid leaking a token handle during SSPI authentication
      (Christian Ullrich)
     </para>
    </listitem>

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    <listitem>
     <para>
      Fix <application>psql</>'s <literal>\det</> command to interpret its
      pattern argument the same way as other <literal>\d</> commands with
      potentially schema-qualified patterns do (Reece Hart)
     </para>
    </listitem>

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    <listitem>
     <para>
      In <application>pg_ctl</> on Windows, check service status to decide
      where to send output, rather than checking if standard output is a
      terminal (Michael Paquier)
     </para>
    </listitem>

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    <listitem>
     <para>
      Fix assorted corner-case bugs in <application>pg_dump</>'s processing
      of extension member objects (Tom Lane)
     </para>
    </listitem>

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    <listitem>
     <para>
      Fix improper quoting of domain constraint names
      in <application>pg_dump</> (Elvis Pranskevichus)
     </para>
    </listitem>

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    <listitem>
     <para>
      Make <application>pg_dump</> mark a view's triggers as needing to be
      processed after its rule, to prevent possible failure during
      parallel <application>pg_restore</> (Tom Lane)
     </para>
    </listitem>

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    <listitem>
     <para>
      Install guards in <application>pgbench</> against corner-case overflow
      conditions during evaluation of script-specified division or modulo
      operators (Fabien Coelho, Michael Paquier)
     </para>
    </listitem>

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    <listitem>
     <para>
      Suppress useless warning message when <application>pg_receivexlog</>
      connects to a pre-9.4 server (Marco Nenciarini)
     </para>
    </listitem>

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    <listitem>
     <para>
      Avoid dump/reload problems when using both <application>plpython2</>
      and <application>plpython3</> (Tom Lane)
     </para>

     <para>
      In principle, both versions of <application>PL/Python</> can be used in
      the same database, though not in the same session (because the two
      versions of <application>libpython</> cannot safely be used concurrently).
      However, <application>pg_restore</> and <application>pg_upgrade</> both
      do things that can fall foul of the same-session restriction.  Work
      around that by changing the timing of the check.
     </para>
    </listitem>

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    <listitem>
     <para>
      Fix <application>PL/Python</> regression tests to pass with Python 3.5
      (Peter Eisentraut)
     </para>
    </listitem>

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    <listitem>
     <para>
      Prevent certain <application>PL/Java</> parameters from being set by
      non-superusers (Noah Misch)
     </para>

     <para>
      This change mitigates a <application>PL/Java</> security bug
      (CVE-2016-0766), which was fixed in <application>PL/Java</> by marking
      these parameters as superuser-only.  To fix the security hazard for
      sites that update <productname>PostgreSQL</> more frequently
      than <application>PL/Java</>, make the core code aware of them also.
     </para>
    </listitem>

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    <listitem>
     <para>
      Fix <application>ecpg</>-supplied header files to not contain comments
      continued from a preprocessor directive line onto the next line
      (Michael Meskes)
     </para>

     <para>
      Such a comment is rejected by <application>ecpg</>.  It's not yet clear
      whether <application>ecpg</> itself should be changed.
     </para>
    </listitem>

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    <listitem>
     <para>
      Fix <function>hstore_to_json_loose()</>'s test for whether
      an <type>hstore</> value can be converted to a JSON number (Tom Lane)
     </para>

     <para>
      Previously this function could be fooled by non-alphanumeric trailing
      characters, leading to emitting syntactically-invalid JSON.
     </para>
    </listitem>

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    <listitem>
     <para>
      In <filename>contrib/postgres_fdw</>, fix bugs triggered by use
      of <literal>tableoid</> in data-modifying commands (Etsuro Fujita,
      Robert Haas)
     </para>
    </listitem>

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    <listitem>
     <para>
      Fix ill-advised restriction of <literal>NAMEDATALEN</> to be less
      than 256 (Robert Haas, Tom Lane)
     </para>
    </listitem>

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    <listitem>
     <para>
      Improve reproducibility of build output by ensuring filenames are given
      to the linker in a fixed order (Christoph Berg)
     </para>

     <para>
      This avoids possible bitwise differences in the produced executable
      files from one build to the next.
     </para>
    </listitem>

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    <listitem>
     <para>
      Ensure that <filename>dynloader.h</> is included in the installed
      header files in MSVC builds (Bruce Momjian, Michael Paquier)
     </para>
    </listitem>

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    <listitem>
     <para>
      Update time zone data files to <application>tzdata</> release 2016a for
      DST law changes in Cayman Islands, Metlakatla, and Trans-Baikal
      Territory (Zabaykalsky Krai), plus historical corrections for Pakistan.
     </para>
    </listitem>

   </itemizedlist>

  </sect2>
 </sect1>

 <sect1 id="release-9-5">
  <title>Release 9.5</title>

  <note>
   <title>Release Date</title>
   <simpara>2016-01-07</simpara>
  </note>

  <sect2>
   <title>Overview</title>

   <para>
    Major enhancements in <productname>PostgreSQL</> 9.5 include:
   </para>

   <!-- This list duplicates items below, but without authors or details-->

   <itemizedlist>

    <listitem>
     <para>
      Allow <link linkend="sql-on-conflict"><command>INSERT</></>s
      that would generate constraint conflicts to be turned into
      <command>UPDATE</>s or ignored
     </para>
    </listitem>

    <listitem>
     <para>
      Add <literal>GROUP BY</> analysis features <link
      linkend="queries-grouping-sets"><literal>GROUPING SETS</></>,
      <link linkend="queries-grouping-sets"><literal>CUBE</></> and
      <link linkend="queries-grouping-sets"><literal>ROLLUP</></>
     </para>
    </listitem>

    <listitem>
     <para>
      Add <link linkend="ddl-rowsecurity">row-level security control</>
     </para>
    </listitem>

    <listitem>
     <para>
      Create mechanisms for tracking
      the <link linkend="replication-origins">progress of replication</>,
      including methods for identifying the origin of individual changes
      during logical replication
     </para>
    </listitem>

    <listitem>
     <para>
      Add <link linkend="BRIN">Block Range Indexes</> (<acronym>BRIN</>)
     </para>
    </listitem>

    <listitem>
     <para>
      Substantial performance improvements for sorting
     </para>
    </listitem>

    <listitem>
     <para>
      Substantial performance improvements for multi-CPU machines
     </para>
    </listitem>

   </itemizedlist>

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

  </sect2>

  <sect2>

  <title>Migration to Version 9.5</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 9.5 contains a number of changes that may affect compatibility
    with previous releases.  Observe the following incompatibilities:
   </para>

   <itemizedlist>

    <listitem>
<!--
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-->
     <para>
      Adjust <link linkend="sql-precedence">operator precedence</>
      to match the <acronym>SQL</> standard (Tom Lane)
     </para>

     <para>
      The precedence of <literal>&lt;=</literal>, <literal>&gt;=</literal>
      and <literal>&lt;&gt;</literal> has been reduced to match that of
      <literal>&lt;</literal>, <literal>&gt;</literal>
      and <literal>=</literal>.  The precedence of <literal>IS</> tests
      (e.g., <replaceable>x</> <literal>IS NULL</>) has been reduced to be
      just below these six comparison operators.
      Also, multi-keyword operators beginning with <literal>NOT</> now have
      the precedence of their base operator (for example, <literal>NOT
      BETWEEN</> now has the same precedence as <literal>BETWEEN</>) whereas
      before they had inconsistent precedence, behaving like <literal>NOT</>
      with respect to their left operand but like their base operator with
      respect to their right operand.  The new configuration
      parameter <xref linkend="guc-operator-precedence-warning"> can be
      enabled to warn about queries in which these precedence changes result
      in different parsing choices.
     </para>
    </listitem>

    <listitem>
<!--
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-->
     <para>
      Change <xref linkend="app-pg-ctl">'s default shutdown mode from
      <literal>smart</> to <literal>fast</> (Bruce Momjian)
     </para>

     <para>
      This means the default behavior will be to forcibly cancel existing
      database sessions, not simply wait for them to exit.
     </para>
    </listitem>

    <listitem>
<!--
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-->
     <para>
      Use assignment cast behavior for data type conversions
      in <application>PL/pgSQL</> assignments, rather than converting to and
      from text (Tom Lane)
     </para>

     <para>
      This change causes conversions of Booleans to strings to
      produce <literal>true</> or <literal>false</>, not <literal>t</>
      or <literal>f</>.  Other type conversions may succeed in more cases
      than before; for example, assigning a numeric value <literal>3.9</> to
      an integer variable will now assign 4 rather than failing.  If no
      assignment-grade cast is defined for the particular source and
      destination types, <application>PL/pgSQL</> will fall back to its old
      I/O conversion behavior.
     </para>
    </listitem>

    <listitem>
<!--
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-->
     <para>
      Allow characters in <link linkend="libpq-connect-options">server
      command-line options</> to be escaped with a backslash (Andres Freund)
     </para>

     <para>
      Formerly, spaces in the options string always separated options, so
      there was no way to include a space in an option value.  Including
      a backslash in an option value now requires writing <literal>\\</>.
     </para>
    </listitem>

    <listitem>
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-->
     <para>
      Change the default value of the GSSAPI <link
      linkend="gssapi-auth"><varname>include_realm</></> parameter to 1, so
      that by default the realm is not removed from a <acronym>GSS</>
      or <acronym>SSPI</> principal name (Stephen Frost)
     </para>
    </listitem>

    <listitem>
<!--
2015-02-23 [88e9823] Heikki..: Replace checkpoint_segments with min_wal_size a..
2015-03-15 [a0f5954] Andres..: Increase max_wal_size's default from 128MB to 1..
2015-06-29 [d661532] Heikki..: Also trigger restartpoints based on max_wal_siz..
-->
     <para>
      Replace configuration parameter <varname>checkpoint_segments</>
      with <xref linkend="guc-min-wal-size">
      and <xref linkend="guc-max-wal-size"> (Heikki Linnakangas)
     </para>

     <para>
      If you previously adjusted <varname>checkpoint_segments</varname>, the
      following formula will give you an approximately equivalent setting:
<programlisting>
max_wal_size = (3 * checkpoint_segments) * 16MB
</programlisting>
      Note that the default setting for <varname>max_wal_size</varname> is
      much higher than the default <varname>checkpoint_segments</varname> used
      to be, so adjusting it might no longer be necessary.
     </para>
    </listitem>

      <listitem>
<!--
2014-06-18 [df8b7bc] Tom Lane: Improve our mechanism for controlling the Linux..
-->
       <para>
        Control the Linux <acronym>OOM</> killer via new environment
        variables <link
        linkend="linux-memory-overcommit"><envar>PG_OOM_ADJUST_FILE</></>
        and <link
        linkend="linux-memory-overcommit"><envar>PG_OOM_ADJUST_VALUE</></>,
        instead of compile-time options <literal>LINUX_OOM_SCORE_ADJ</> and
        <literal>LINUX_OOM_ADJ</>
        (Gurjeet Singh)
       </para>
      </listitem>

    <listitem>
<!--
2015-10-20 [b06f1f2] Robert..: Put back ssl_renegotiation_limit parameter, bu..
2015-07-28 [6087d95] Andres..: Remove ssl renegotiation support.
-->
     <para>
      Decommission server configuration
      parameter <varname>ssl_renegotiation_limit</>, which was deprecated
      in earlier releases (Andres Freund)
     </para>

     <para>
      While SSL renegotiation is a good idea in theory, it has caused enough
      bugs to be considered a net negative in practice, and it is due to be
      removed from future versions of the relevant standards.  We have
      therefore removed support for it from <productname>PostgreSQL</>.
      The <varname>ssl_renegotiation_limit</> parameter still exists, but
      cannot be set to anything but zero (disabled).  It's not documented
      anymore, either.
     </para>
    </listitem>

    <listitem>
<!--
2014-11-05 [525a489] Tom Lane: Remove the last vestige of server-side autocomm..
-->
     <para>
      Remove server configuration parameter <varname>autocommit</>, which
      was already deprecated and non-operational (Tom Lane)
     </para>
    </listitem>

    <listitem>
<!--
2015-03-06 [bb8582a] Peter ..: Remove rolcatupdate
-->
     <para>
      Remove the <link linkend="catalog-pg-authid"><structname>pg_authid</></>
      catalog's <structfield>rolcatupdate</> field, as it had no usefulness
      (Adam Brightwell)
     </para>
    </listitem>

    <listitem>
<!--
2015-12-13 [28c3667] Magnus..: Consistently set all fields in pg_stat_replica..
-->
     <para>
      The <link
      linkend="monitoring-stats-views-table"><structname>pg_stat_replication</></link>
      system view's <structfield>sent</> field is now NULL, not zero, when
      it has no valid value (Magnus Hagander)
     </para>
    </listitem>

    <listitem>
<!--
2015-07-17 [89ddd29] Andrew..: Support JSON negative array subscripts everywh..
-->
     <para>
      Allow <type>json</> and <type>jsonb</> array extraction operators to
      accept negative subscripts, which count from the end of JSON arrays
      (Peter Geoghegan, Andrew Dunstan)
     </para>

     <para>
      Previously, these operators returned <literal>NULL</> for negative
      subscripts.
     </para>
    </listitem>

   </itemizedlist>

  </sect2>

  <sect2>
   <title>Changes</title>

   <para>
    Below you will find a detailed account of the changes between
    <productname>PostgreSQL</productname> 9.5 and the previous major
    release.
   </para>

   <sect3>
    <title>Server</title>

    <sect4>
     <title>Indexes</title>

     <itemizedlist>

      <listitem>
<!--
2014-11-07 [7516f52] Alvaro..: BRIN: Block Range Indexes
2015-05-05 [3b6db1f] Alvaro..: Add geometry/range functions to support BRIN in..
2015-05-15 [b0b7be6] Alvaro..: Add BRIN infrastructure for "inclusion" opclasses
-->
       <para>
        Add <link linkend="BRIN">Block Range Indexes</> (<acronym>BRIN</>)
        (&Aacute;lvaro Herrera)
       </para>

       <para>
        <acronym>BRIN</> indexes store only summary data (such as minimum
        and maximum values) for ranges of heap blocks.  They are therefore
        very compact and cheap to update; but if the data is naturally
        clustered, they can still provide substantial speedup of searches.
       </para>
      </listitem>

      <listitem>
<!--
2015-05-15 [35fcb1b] Heikki..: Allow GiST distance function to return merely ..
-->
       <para>
        Allow queries to perform accurate distance filtering of
        bounding-box-indexed objects (polygons, circles) using <link
        linkend="GiST">GiST</> indexes (Alexander Korotkov, Heikki
        Linnakangas)
       </para>

       <para>
        Previously, to exploit such an index a subquery had to be used to
        select a large number of rows ordered by bounding-box distance, and
        the result then had to be filtered further with a more accurate
        distance calculation.
       </para>
      </listitem>

      <listitem>
<!--
2015-03-26 [d04c8ed] Heikki..: Add support for index-only scans in GiST.
2015-03-27 [e09b483] Heikki..: Add index-only scan support to btree_gist.
2015-03-28 [3a20b0e] Heikki..: Add index-only scan support to inet GiST opclass.
2015-03-30 [0633a60] Heikki..: Add index-only scan support to range type GiST ..
-->
       <para>
        Allow <link linkend="GiST">GiST</> indexes to perform index-only
        scans (Anastasia Lubennikova, Heikki Linnakangas, Andreas Karlsson)
       </para>
      </listitem>

      <listitem>
<!--
Add GUC and storage parameter to set the maximum size of GIN pending list.
-->
       <para>
        Add configuration parameter <xref linkend="guc-gin-pending-list-limit">
        to control the size of <acronym>GIN</> pending lists (Fujii Masao)
       </para>

       <para>
        This value can also be set on a per-index basis as an index storage
        parameter.  Previously the pending-list size was controlled
        by <xref linkend="guc-work-mem">, which was awkward because
        appropriate values for <varname>work_mem</> are often much too large
        for this purpose.
       </para>
      </listitem>

      <listitem>
<!--
2014-09-10 [84aa8ba] Bruce ..: Issue a warning during the creation of hash in..
-->
       <para>
        Issue a warning during the creation of <link
        linkend="indexes-types">hash</> indexes because they are not
        crash-safe (Bruce Momjian)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

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

     <itemizedlist>

      <listitem>
<!--
2015-01-19 [4ea51cd] Robert..: Use abbreviated keys for faster sorting of text..
2014-09-19 [e246b3d] Robert..: Add a fast pre-check for equality of equal-leng..
2015-05-13 [78efd5c] Robert..: Extend abbreviated key infrastructure to datum ..
-->
       <para>
        Improve the speed of sorting of <type>varchar</>, <type>text</>,
        and <type>numeric</> fields via <quote>abbreviated</> keys
        (Peter Geoghegan, Andrew Gierth, Robert Haas)
       </para>
      </listitem>

      <listitem>
<!--
2014-11-07 [5ea86e6] Robert..: Use the sortsupport infrastructure in more cas..
-->
       <para>
        Extend the infrastructure that allows sorting to be performed by
        inlined, non-<acronym>SQL</acronym>-callable comparison functions to
        cover <command>CREATE INDEX</>, <command>REINDEX</>, and
        <command>CLUSTER</> (Peter Geoghegan)
       </para>
      </listitem>

      <listitem>
<!--
2014-09-10 [45f6240] Heikki..: Pack tuples in a hash join batch densely, to sa..
2014-09-12 [8cce08f] Robert..: Change NTUP_PER_BUCKET to 1 to improve hash joi..
2014-10-13 [30d7ae3] Kevin ..: Increase number of hash join buckets for undere..
-->
       <para>
        Improve performance of hash joins (Tomas Vondra, Robert Haas)
       </para>
      </listitem>

      <listitem>
<!--
2014-09-25 [5d7962c] Robert..: Change locking regimen around buffer replacement.
2014-12-25 [d72731a] Andres..: Lockless StrategyGetBuffer clock sweep hot path.
-->
       <para>
        Improve concurrency of shared buffer replacement
        (Robert Haas, Amit Kapila, Andres Freund)
       </para>
      </listitem>

      <listitem>
<!--
2015-03-25 [2ed5b87f] Kevin ..: Reduce pinning and buffer content locking for b..
-->
       <para>
        Reduce the number of page locks and pins during index scans (Kevin Grittner)
       </para>

       <para>
        The primary benefit of this is to allow index vacuums to be blocked
        less often.
       </para>
      </listitem>

      <listitem>
<!--
2014-08-30 [4b4b680] Andres..: Make backend local tracking of buffer pins memo..
2015-01-19 [2d115e4] Andres..: Fix various shortcomings of the new PrivateRefC..
-->
       <para>
        Make per-backend tracking of buffer pins more memory-efficient
        (Andres Freund)
       </para>
      </listitem>

      <listitem>
<!--
2014-12-25 [ab5194e] Andres..: Improve LWLock scalability.
-->
       <para>
        Improve lock scalability (Andres Freund)
       </para>

       <para>
        This particularly addresses scalability problems when running on
        systems with multiple <acronym>CPU</> sockets.
       </para>
      </listitem>

      <listitem>
<!--
2014-07-15 [f15821e] Tom Lane: Allow join removal in some cases involving a le..
-->
       <para>
        Allow the optimizer to remove unnecessary references to left-joined
        subqueries (David Rowley)
       </para>
      </listitem>

      <listitem>
<!--
2014-06-27 [d222585] Tom Lane: Allow pushdown of WHERE quals into subqueries w..
-->
       <para>
        Allow pushdown of query restrictions into subqueries with <link
        linkend="tutorial-window">window functions</>, where appropriate
        (David Rowley)
       </para>
      </listitem>

      <listitem>
<!--
2015-04-27 [dcbf594]  Stephe..: Improve qual pushdown for RLS and SB views
-->
       <para>
        Allow a non-leakproof function to be pushed down into a security
        barrier view if the function does not receive any view output
        columns (Dean Rasheed)
       </para>
      </listitem>

      <listitem>
<!--
2015-09-24 [45d256c] Tom Lane: Allow planner to use expression-index stats fo..
-->
       <para>
        Teach the planner to use statistics obtained from an expression
        index on a boolean-returning function, when a matching function call
        appears in <literal>WHERE</> (Tom Lane)
       </para>
      </listitem>

      <listitem>
<!--
2015-09-23 [cfb2024] Tom Lane: Make ANALYZE compute basic statistics even for..
-->
       <para>
        Make <command>ANALYZE</> compute basic statistics (null fraction and
        average column width) even for columns whose data type lacks an
        equality function (Oleksandr Shulgin)
       </para>
      </listitem>

      <listitem>
<!--
2014-11-04 [5028f22] Heikki..: Switch to CRC-32C in WAL and other places.
2015-02-10 [025c024] Heikki..: Speed up CRC calculation using slicing-by-8 alg..
2015-04-14 [3dc2d62] Heikki..: Use Intel SSE 4.2 CRC instructions where availa..

-->
       <para>
        Speed up <acronym>CRC</> (cyclic redundancy check) computations
        and switch to CRC-32C (Abhijit Menon-Sen, Heikki Linnakangas)
       </para>
      </listitem>

      <listitem>
<!--
2015-01-16 [f5ae3ba] Andres..: Make tbm_add_tuples more efficient by caching t..
2015-01-16 [779fdcd] Tom Lane: Improve new caching logic in tbm_add_tuples().
-->
       <para>
        Improve bitmap index scan performance (Teodor Sigaev, Tom Lane)
       </para>
      </listitem>

      <listitem>
<!--
2014-07-01 [9f03ca9] Robert..: Avoid copying index tuples when building an ind..
-->
       <para>
        Speed up <command>CREATE INDEX</> by avoiding unnecessary memory
        copies (Robert Haas)
       </para>
      </listitem>

      <listitem>
<!--
2014-10-02 [3acc10c9] Robert..: Increase the number of buffer mapping partitio..
-->
       <para>
        Increase the number of buffer mapping partitions (Amit Kapila,
        Andres Freund, Robert Haas)
       </para>

       <para>
        This improves performance for highly concurrent workloads.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Monitoring</title>

     <itemizedlist>

      <listitem>
<!--
2015-04-03 [4ff695b1] Alvaro..: Add log_min_autovacuum_duration per-table option
-->
       <para>
        Add per-table autovacuum logging control via new
        <varname>log_min_autovacuum_duration</> storage parameter
        (Michael Paquier)
       </para>
      </listitem>

      <listitem>
<!--
2014-06-29 [51adcaa] Andres..: Add cluster_name GUC which is included in proce..
-->
       <para>
        Add new configuration parameter <xref linkend="guc-cluster-name">
        (Thomas Munro)
       </para>

       <para>
        This string, typically set in <link
        linkend="config-setting-configuration-file"><filename>postgresql.conf</></>,
        allows clients to identify the cluster.  This name also appears
        in the process title of all server processes, allowing for easier
        identification of processes belonging to the same cluster.
       </para>
      </listitem>

      <listitem>
<!--
2014-09-13 [fe550b2] Tom Lane: Invent PGC_SU_BACKEND and mark log_connections..
-->
       <para>
        Prevent non-superusers from changing <xref
        linkend="guc-log-disconnections"> on connection startup (Fujii Masao)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title><acronym>SSL</></title>

     <itemizedlist>

      <listitem>
<!--
2014-09-12 [acd08d7] Heikki..: Support Subject Alternative Names in SSL server..
-->
       <para>
        Check <link linkend="libpq-ssl"><quote>Subject Alternative
        Names</></> in <acronym>SSL</> server certificates, if present
        (Alexey Klyukin)
       </para>

       <para>
        When they are present, this replaces checks against the certificate's
        <quote>Common Name</>.
       </para>
      </listitem>

      <listitem>
<!--
2015-04-12 [9029f4b] Magnus..: Add system view pg_stat_ssl
-->
       <para>
        Add system view <link
        linkend="pg-stat-ssl-view"><structname>pg_stat_ssl</></> to report
        <acronym>SSL</> connection information (Magnus Hagander)
       </para>
      </listitem>

      <listitem>
<!--
2015-02-03 [91fa7b4] Heikki..: Add API functions to libpq to interrogate SSL ..
-->
       <para>
        Add <application>libpq</> functions to return <acronym>SSL</>
        information in an implementation-independent way (Heikki Linnakangas)
       </para>

       <para>
        While <link linkend="libpq-pqgetssl"><function>PQgetssl()</></> can
        still be used to call <productname>OpenSSL</> functions, it is now
        considered deprecated because future versions
        of <application>libpq</> might support other <acronym>SSL</>
        implementations.  When possible, use the new
        functions <link
        linkend="libpq-pqsslattribute"><function>PQsslAttribute()</></>, <link
        linkend="libpq-pqsslattributenames"><function>PQsslAttributeNames()</></>,
        and <link linkend="libpq-pqsslinuse"><function>PQsslInUse()</></>
        to obtain <acronym>SSL</> information in
        an <acronym>SSL</>-implementation-independent way.
       </para>
      </listitem>

      <listitem>
<!--
2015-04-09 [8a0d34e4] Peter ..: libpq: Don't overwrite existing OpenSSL thread..
-->
       <para>
        Make <application>libpq</> honor any <productname>OpenSSL</>
        thread callbacks (Jan Urbanski)
       </para>

       <para>
        Previously they were overwritten.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Server Settings</title>

     <itemizedlist>

      <listitem>
<!--
2015-02-23 [88e9823] Heikki..: Replace checkpoint_segments with min_wal_size a..
2015-03-15 [a0f5954] Andres..: Increase max_wal_size's default from 128MB to 1..
2015-06-29 [d661532] Heikki..: Also trigger restartpoints based on max_wal_siz..
-->
       <para>
        Replace configuration parameter <varname>checkpoint_segments</>
        with <xref linkend="guc-min-wal-size">
        and <xref linkend="guc-max-wal-size"> (Heikki Linnakangas)
       </para>

       <para>
        This change allows the allocation of a large number of <acronym>WAL</>
        files without keeping them after they are no longer needed.
        Therefore the default for <varname>max_wal_size</> has been set
        to <literal>1GB</>, much larger than the old default
        for <varname>checkpoint_segments</>.
        Also note that standby servers perform restartpoints to try to limit
        their WAL space consumption to <varname>max_wal_size</>; previously
        they did not pay any attention to <varname>checkpoint_segments</>.
       </para>
      </listitem>

      <listitem>
<!--
2014-06-18 [df8b7bc] Tom Lane: Improve our mechanism for controlling the Linux..
-->
       <para>
        Control the Linux <acronym>OOM</> killer via new environment
        variables <link
        linkend="linux-memory-overcommit"><envar>PG_OOM_ADJUST_FILE</></>
        and <link
        linkend="linux-memory-overcommit"><envar>PG_OOM_ADJUST_VALUE</></>
        (Gurjeet Singh)
       </para>

       <para>
        The previous <acronym>OOM</> control infrastructure involved
        compile-time options <literal>LINUX_OOM_SCORE_ADJ</> and
        <literal>LINUX_OOM_ADJ</>, which are no longer supported.
        The new behavior is available in all builds.
       </para>
      </listitem>

      <listitem>
<!--
2014-12-03 [73c986a] Alvaro..: Keep track of transaction commit timestamps
-->
       <para>
        Allow recording of transaction
        commit time stamps when configuration parameter <xref
        linkend="guc-track-commit-timestamp">
        is enabled (&Aacute;lvaro Herrera, Petr Jel&iacute;nek)
       </para>

       <para>
        Time stamp information can be accessed using functions <link
        linkend="functions-commit-timestamp"><function>pg_xact_commit_timestamp()</></>
        and <function>pg_last_committed_xact()</>.
       </para>
      </listitem>

      <listitem>
<!--
2014-12-22 [584e35d] Peter ..: Change local_preload_libraries to PGC_USERSET
-->
       <para>
        Allow <xref linkend="guc-local-preload-libraries"> to be set
        by <command>ALTER ROLE SET</> (Peter Eisentraut, Kyotaro Horiguchi)
       </para>
      </listitem>

      <listitem>
<!--
2015-04-03 [a75fb9b] Alvaro..: Have autovacuum workers listen to SIGHUP, too
-->
       <para>
        Allow <link linkend="autovacuum">autovacuum workers</>
        to respond to configuration parameter changes during a run
        (Michael Paquier)
       </para>
      </listitem>

      <listitem>
<!--
2014-06-20 [3bdcf6a] Andres..: Don't allow to disable backend assertions via t..
-->
       <para>
        Make configuration parameter <xref linkend="guc-debug-assertions">
        read-only (Andres Freund)
       </para>

       <para>
        This means that assertions can no longer be turned
        off if they were enabled at compile time, allowing for more
        efficient code optimization.  This change also removes the <link
        linkend="app-postgres-options">postgres</> <option>-A</> option.
       </para>
      </listitem>

      <listitem>
<!--
2014-10-18 [7feaccc] Peter ..: Allow setting effective_io_concurrency even on..
-->
       <para>
        Allow setting <xref linkend="guc-effective-io-concurrency"> on
        systems where it has no effect (Peter Eisentraut)
       </para>
      </listitem>

      <listitem>
<!--
2015-05-08 [a97e0c3] Stephe..: Add pg_file_settings view and function
2015-06-28 [62d16c7] Tom Lane: Improve design and implementation of pg_file_se..
-->
       <para>
        Add system view <link
        linkend="view-pg-file-settings"><structname>pg_file_settings</></>
        to show the contents of the server's configuration files
        (Sawada Masahiko)
       </para>
      </listitem>

      <listitem>
<!--
2015-05-14 [a486e35] Peter ..: Add pg_settings.pending_restart column
-->
       <para>
        Add <structname>pending_restart</> to the system view <link
        linkend="view-pg-settings"><structname>pg_settings</></> to
        indicate a change has been made but will not take effect until a
        database restart (Peter Eisentraut)
       </para>
      </listitem>

      <listitem>
<!--
2014-09-02 [bd3b7a9] Fujii ..: Support ALTER SYSTEM RESET command.
-->
       <para>
        Allow <link linkend="SQL-ALTERSYSTEM"><command>ALTER SYSTEM</></>
        values to be reset with <command>ALTER SYSTEM RESET</> (Vik
        Fearing)
       </para>

       <para>
        This command removes the specified setting
        from <filename>postgresql.auto.conf</>.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

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

     <itemizedlist>

      <listitem>
<!--
2015-04-29 [5aa2350] Andres..: Introduce replication progress tracking infrast..
-->
       <para>
        Create mechanisms for tracking
        the <link linkend="replication-origins">progress of replication</>,
        including methods for identifying the origin of individual changes
        during logical replication (Andres Freund)
       </para>

       <para>
        This is helpful when implementing replication solutions.
       </para>
      </listitem>

      <listitem>
<!--
2015-09-26 [bd7c348] Andres..: Rework the way multixact truncations work.
2015-09-26 [6e8af37] Andres..: Remove legacy multixact truncation support.
-->
       <para>
        Rework truncation of the multixact commit log to be properly
        WAL-logged (Andres Freund)
       </para>

       <para>
        This makes things substantially simpler and more robust.
       </para>
      </listitem>

      <listitem>
<!--
2014-11-25 [aedccb1] Simon ..: action_at_recovery_target recovery config option
2014-12-07 [b8e33a8] Simon ..: Tweaks for recovery_target_action
2015-03-15 [51c11a7] Andres..: Remove pause_at_recovery_target recovery.conf s..
-->
       <para>
        Add <link linkend="recovery-config"><filename>recovery.conf</></>
        parameter <link
        linkend="recovery-target-action"><varname>recovery_target_action</></>
        to control post-recovery activity (Petr Jel&iacute;nek)
       </para>

       <para>
        This replaces the old parameter <varname>pause_at_recovery_target</>.
       </para>
      </listitem>

      <listitem>
<!--
2015-05-15 [ffd3774] Heikki..: Add archive_mode='always' option.
-->
       <para>
        Add new <xref linkend="guc-archive-mode"> value
        <literal>always</> to allow standbys to always archive received
        <acronym>WAL</> files (Fujii Masao)
       </para>
      </listitem>

      <listitem>
<!--
2015-02-23 [5d2b45e] Fujii ..: Add GUC to control the time to wait before retr..
-->
       <para>
        Add configuration
        parameter <xref linkend="guc-wal-retrieve-retry-interval"> to
        control <acronym>WAL</> read retry after failure
        (Alexey Vasiliev, Michael Paquier)
       </para>

       <para>
        This is particularly helpful for warm standbys.
       </para>
      </listitem>

      <listitem>
<!--
2015-03-11 [57aa5b2] Fujii ..: Add GUC to enable compression of full page imag..
-->
       <para>
        Allow compression of full-page images stored in <acronym>WAL</>
        (Rahila Syed, Michael Paquier)
       </para>

       <para>
        This feature reduces WAL volume, at the cost of more CPU time spent
        on WAL logging and WAL replay.  It is controlled by a new
        configuration parameter <xref linkend="guc-wal-compression">, which
        currently is off by default.
       </para>
      </listitem>

      <listitem>
<!--
2015-05-08 [de76884] Heikki..: At promotion, archive last segment from old tim..
-->
       <para>
        Archive <acronym>WAL</> files with suffix <literal>.partial</>
        during standby promotion (Heikki Linnakangas)
       </para>
      </listitem>

      <listitem>
<!--
2014-09-13 [4ad2a54] Fujii ..: Add GUC to enable logging of replication comman..
-->
       <para>
        Add configuration parameter <xref
        linkend="guc-log-replication-commands">
        to log replication commands (Fujii Masao)
       </para>

       <para>
        By default, replication commands, e.g. <link
        linkend="protocol-replication"><literal>IDENTIFY_SYSTEM</></>,
        are not logged, even when <xref linkend="guc-log-statement"> is set
        to <literal>all</>.
       </para>
      </listitem>

      <listitem>
<!--
2015-04-21 [d811c03] Andres..: Add 'active_in' column to pg_replication_slots.
-->
       <para>
        Report the processes holding replication slots in <link
        linkend="catalog-pg-replication-slots"><structname>pg_replication_slots</></>
        (Craig Ringer)
       </para>

       <para>
        The new output column is <structname>active_pid</>.
       </para>
      </listitem>

      <listitem>
<!--
2014-11-25 [b3fc672] Heikki..: Allow using connection URI in primary_conninfo.
-->
       <para>
        Allow <filename>recovery.conf</>'s <link
        linkend="primary-conninfo"><varname>primary_conninfo</></> setting to
        use connection <acronym>URI</>s, e.g. <literal>postgres://</>
        (Alexander Shulgin)
       </para>
      </listitem>

     </itemizedlist>

   </sect3>

   <sect3>
    <title>Queries</title>

     <itemizedlist>

      <listitem>
<!--
2015-05-08 [168d580] Andres..: Add support for INSERT ... ON CONFLICT DO NOTHI..
2015-05-08 [2c8f483] Andres..: Represent columns requiring insert and update p..
-->
       <para>
        Allow <link linkend="sql-on-conflict"><command>INSERT</></>s
        that would generate constraint conflicts to be turned into
        <command>UPDATE</>s or ignored (Peter Geoghegan, Heikki
        Linnakangas, Andres Freund)
       </para>

       <para>
        The syntax is <command>INSERT ... ON CONFLICT DO NOTHING/UPDATE</>.
        This is the Postgres implementation of the popular
        <command>UPSERT</> command.
       </para>
      </listitem>

      <listitem>
<!--
2015-05-16 [f3d3118] Andres..: Support GROUPING SETS, CUBE and ROLLUP.
-->
       <para>
        Add <literal>GROUP BY</> analysis features <link
        linkend="queries-grouping-sets"><literal>GROUPING SETS</></>,
        <link linkend="queries-grouping-sets"><literal>CUBE</></> and
        <link linkend="queries-grouping-sets"><literal>ROLLUP</></>
        (Andrew Gierth, Atri Sharma)
       </para>
      </listitem>

      <listitem>
<!--
2014-06-18 [8f889b1] Tom Lane: Implement UPDATE tab SET (col1,col2,...) = (SEL..
-->
       <para>
        Allow setting multiple target columns in
        an <link linkend="SQL-UPDATE"><command>UPDATE</></> from the result of
        a single sub-SELECT (Tom Lane)
       </para>

       <para>
        This is accomplished using the syntax <command>UPDATE tab SET
        (col1, col2, ...) = (SELECT ...)</>.
       </para>
      </listitem>

      <listitem>
<!--
2014-10-07 [df630b0] Alvaro..: Implement SKIP LOCKED for row-level locks
-->
       <para>
        Add <link linkend="SQL-SELECT"><command>SELECT</></> option
        <literal>SKIP LOCKED</> to skip locked rows (Thomas Munro)
       </para>

       <para>
        This does not throw an error for locked rows like
        <literal>NOWAIT</> does.
       </para>
      </listitem>

      <listitem>
<!--
2015-05-15 [f6d208d] Simon ..: TABLESAMPLE, SQL Standard and extensible
-->
       <para>
        Add <link linkend="SQL-SELECT"><command>SELECT</></> option
        <literal>TABLESAMPLE</> to return a subset of a table (Petr
        Jel&iacute;nek)
       </para>

       <para>
        This feature supports the SQL-standard table sampling methods.
        In addition, there are provisions
        for <link linkend="tablesample-method">user-defined
        table sampling methods</>.
       </para>
      </listitem>

      <listitem>
<!--
2015-03-11 [e529cd4] Robert..: Suggest to the user the column they may have m..
-->
       <para>
        Suggest possible matches for mistyped column names (Peter
        Geoghegan, Robert Haas)
       </para>
      </listitem>

     </itemizedlist>

   </sect3>

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

     <itemizedlist>

      <listitem>
<!--
2015-01-16 [20af53d] Tom Lane: Show sort ordering options in EXPLAIN output.
-->
       <para>
        Add more details about sort ordering in <link
        linkend="SQL-EXPLAIN"><command>EXPLAIN</></> output (Marius Timmer,
        Lukas Kreft, Arne Scheffer)
       </para>

       <para>
        Details include <literal>COLLATE</>, <literal>DESC</>,
        <literal>USING</>, and <literal>NULLS FIRST</><literal>/LAST</>.
       </para>
      </listitem>

      <listitem>
<!--
2014-12-18 [35192f0] Alvaro..: Have VACUUM log number of skipped pages due to ..
-->
       <para>
        Make <link linkend="SQL-VACUUM"><command>VACUUM</></> log the
        number of pages skipped due to pins (Jim Nasby)
       </para>
      </listitem>

      <listitem>
<!--
2015-02-20 [d42358e] Alvaro..: Have TRUNCATE update pgstat tuple counters
-->
       <para>
        Make <link linkend="SQL-TRUNCATE"><command>TRUNCATE</></> properly
        update the <literal>pg_stat</>* tuple counters (Alexander Shulgin)
       </para>
      </listitem>

       </itemizedlist>

       <sect4>
        <title><xref linkend="SQL-REINDEX"></title>

        <itemizedlist>

      <listitem>
<!--
2014-12-09 [fe263d1] Simon ..: REINDEX SCHEMA
-->
       <para>
        Allow <command>REINDEX</> to reindex an entire schema using the
        <literal>SCHEMA</> option (Sawada Masahiko)
       </para>
      </listitem>

      <listitem>
<!--
2015-05-15 [ecd222e] Fujii ..: Support VERBOSE option in REINDEX command.
-->
       <para>
        Add <literal>VERBOSE</> option to <command>REINDEX</> (Sawada
        Masahiko)
       </para>
      </listitem>

      <listitem>
<!--
2014-12-09 [ae4e688] Simon ..: Silence REINDEX
-->
       <para>
        Prevent <command>REINDEX DATABASE</> and <command>SCHEMA</>
        from outputting object names, unless <literal>VERBOSE</> is used
        (Simon Riggs)
       </para>
      </listitem>

      <listitem>
<!--
2015-04-09 [17d436d] Fujii ..: Remove obsolete FORCE option from REINDEX.
-->
       <para>
        Remove obsolete <literal>FORCE</> option from <command>REINDEX</>
        (Fujii Masao)
       </para>
      </listitem>

      </itemizedlist>

     </sect4>
   </sect3>

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

     <itemizedlist>

      <listitem>
<!--
2014-09-19 [491c029] Stephe..: Row-Level Security Policies (RLS)
-->
       <para>
        Add  <link linkend="ddl-rowsecurity">row-level security control</>
        (Craig Ringer, KaiGai Kohei, Adam Brightwell, Dean Rasheed,
        Stephen Frost)
       </para>

       <para>
        This feature allows row-by-row control over which users can add,
        modify, or even see rows in a table.  This is controlled by new
        commands <link linkend="SQL-CREATEPOLICY"><command>CREATE</></>/<link
        linkend="SQL-ALTERPOLICY"><command>ALTER</></>/<link
        linkend="SQL-DROPPOLICY"><command>DROP POLICY</></> and <link
        linkend="SQL-ALTERTABLE"><command>ALTER TABLE ... ENABLE/DISABLE
        ROW SECURITY</></>.
       </para>
      </listitem>

      <listitem>
<!--
2014-08-22 [f41872d] Alvaro..: Implement ALTER TABLE .. SET LOGGED / UNLOGGED
-->
       <para>
        Allow changing of the <acronym>WAL</acronym>
        logging status of a table after creation with <link
        linkend="SQL-ALTERTABLE"><command>ALTER TABLE ... SET LOGGED /
        UNLOGGED</></> (Fabr&iacute;zio de Royes Mello)
       </para>
      </listitem>

      <listitem>
<!--
2014-08-26 [0076f26] Heikki..: Implement IF NOT EXISTS for CREATE SEQUENCE.
2014-11-06 [08309aa] Fujii ..: Implement IF NOT EXIST for CREATE INDEX.
2014-12-13 [e39b6f9] Andrew..: Add CINE option for CREATE TABLE AS and CREATE ..
-->
       <para>
        Add <literal>IF NOT EXISTS</> clause to <link
        linkend="SQL-CREATETABLEAS"><command>CREATE TABLE AS</></>,
        <link linkend="SQL-CREATEINDEX"><command>CREATE INDEX</></>,
        <link linkend="SQL-CREATESEQUENCE"><command>CREATE SEQUENCE</></>,
        and <link linkend="SQL-CREATEMATERIALIZEDVIEW"><command>CREATE
        MATERIALIZED VIEW</></> (Fabr&iacute;zio de Royes Mello)
       </para>
      </listitem>

      <listitem>
<!--
2015-03-24 [1d8198b] Bruce ..: Add support for ALTER TABLE IF EXISTS ... RENAM..
-->
       <para>
        Add support for <literal>IF EXISTS</> to <link
        linkend="SQL-ALTERTABLE"><command>ALTER TABLE ... RENAME
        CONSTRAINT</></> (Bruce Momjian)
       </para>
      </listitem>

      <listitem>
<!--
2015-03-09 [31eae60] Alvaro..: Allow CURRENT/SESSION_USER to be used in certai..
-->
       <para>
        Allow some DDL commands to accept <literal>CURRENT_USER</>
        or <literal>SESSION_USER</>, meaning the current user or session
        user, in place of a specific user name (Kyotaro Horiguchi,
        &Aacute;lvaro Herrera)
       </para>

       <para>
        This feature is now supported in
        <xref linkend="SQL-ALTERUSER">, <xref linkend="SQL-ALTERGROUP">,
        <xref linkend="SQL-ALTERROLE">, <xref linkend="SQL-GRANT">,
        and <command>ALTER <replaceable>object</> OWNER TO</> commands.
       </para>
      </listitem>

      <listitem>
<!--
2015-06-21 [ad89a5d] Alvaro..: Add transforms to pg_get_object_address and fr..
-->
       <para>
        Support comments on <link linkend="SQL-CREATEDOMAIN">domain
        constraints</> (&Aacute;lvaro Herrera)
       </para>
      </listitem>

      <listitem>
<!--
2015-04-05 [0ef0396] Simon ..: Reduce lock levels of some trigger DDL and add ..
-->
       <para>
        Reduce lock levels of some create and alter trigger and foreign
        key commands (Simon Riggs, Andreas Karlsson)
       </para>
      </listitem>

      <listitem>
<!--
2015-05-11 [fa26424] Stephe..: Allow LOCK TABLE .. ROW EXCLUSIVE MODE with IN..
-->
       <para>
        Allow <link linkend="SQL-LOCK"><command>LOCK TABLE ... ROW EXCLUSIVE
        MODE</></> for those with <command>INSERT</> privileges on the
        target table (Stephen Frost)
       </para>

       <para>
        Previously this command required <command>UPDATE</>, <command>DELETE</>,
        or <command>TRUNCATE</> privileges.
       </para>
      </listitem>

      <listitem>
<!--
2015-03-23 [e5f455f] Tom Lane: Apply table and domain CHECK constraints in nam.
-->
       <para>
        Apply table and domain <literal>CHECK</> constraints in order by name
        (Tom Lane)
       </para>

       <para>
        The previous ordering was indeterminate.
       </para>
      </listitem>

      <listitem>
<!--
2014-07-01 [15c82ef] Tom Lane: Refactor CREATE/ALTER DATABASE syntax so option..
2014-07-01 [fbb1d7d] Tom Lane: Allow CREATE/ALTER DATABASE to manipulate datis..
-->
       <para>
        Allow <link
        linkend="SQL-CREATEDATABASE"><command>CREATE</></>/<link
        linkend="SQL-ALTERDATABASE"><command>ALTER DATABASE</></>
        to manipulate <structname>datistemplate</> and
        <structname>datallowconn</> (Vik Fearing)
       </para>

       <para>
        This allows these per-database settings to be
        changed without manually modifying the <link
        linkend="catalog-pg-database"><structname>pg_database</></>
        system catalog.
       </para>
      </listitem>

     </itemizedlist>

     <sect4>
      <title><link linkend="ddl-foreign-data">Foreign Tables</link></title>

      <itemizedlist>

      <listitem>
<!--
2014-07-10 [59efda3] Tom Lane: Implement IMPORT FOREIGN SCHEMA.
-->
       <para>
        Add support for <xref linkend="SQL-IMPORTFOREIGNSCHEMA">
        (Ronan Dunklau, Michael Paquier, Tom Lane)
       </para>

       <para>
        This command allows automatic creation of local foreign tables
        that match the structure of existing tables on a remote server.
       </para>
      </listitem>

      <listitem>
<!--
2014-12-17 [fc2ac1f] Tom Lane: Allow CHECK constraints to be placed on foreign..
-->
       <para>
        Allow <literal>CHECK</> constraints to be placed on foreign tables
        (Shigeru Hanada, Etsuro Fujita)
       </para>

       <para>
        Such constraints are assumed to be enforced on the remote server,
        and are not enforced locally.  However, they are assumed to hold for
        purposes of query optimization, such
        as <link linkend="ddl-partitioning-constraint-exclusion">constraint
        exclusion</>.
       </para>
      </listitem>

      <listitem>
<!--
2015-03-22 [cb1ca4d] Tom Lane: Allow foreign tables to participate in inherita..
-->
       <para>
        Allow foreign tables to participate in inheritance (Shigeru Hanada,
        Etsuro Fujita)
       </para>

       <para>
        To let this work naturally, foreign tables are now allowed to have
        check constraints marked as not valid, and to set storage
        and <type>OID</> characteristics, even though these operations are
        effectively no-ops for a foreign table.
       </para>
      </listitem>

      <listitem>
<!--
2015-05-01 [e7cb7ee] Robert..: Allow FDWs and custom scan providers to replace..
2015-05-10 [1a8a4e5] Tom Lane: Code review for foreign/custom join pushdown pa..
-->
       <para>
        Allow foreign data wrappers and custom scans to implement join
        pushdown (KaiGai Kohei)
       </para>
      </listitem>

     </itemizedlist>

     </sect4>

     <sect4>
      <title><link linkend="event-triggers">Event Triggers</link></title>

      <itemizedlist>

       <listitem>
<!--
2015-05-11 [b488c58] Alvaro..: Allow on-the-fly capture of DDL event details
-->
        <para>
         Whenever a <literal>ddl_command_end</> event trigger is installed,
         capture details of <acronym>DDL</> activity for it to inspect
         (&Aacute;lvaro Herrera)
        </para>

        <para>
         This information is available through a set-returning function <link
         linkend="pg-event-trigger-ddl-command-end-functions"><function>pg_event_trigger_ddl_commands()</></link>,
         or by inspection of C data structures if that function doesn't
         provide enough detail.
        </para>
       </listitem>

       <listitem>
<!--
2014-12-08 [618c943] Simon ..: Event Trigger for table_rewrite
-->
        <para>
         Allow event triggers on table rewrites caused by <link
         linkend="SQL-ALTERTABLE"><command>ALTER TABLE</></> (Dimitri
         Fontaine)
        </para>
       </listitem>

       <listitem>
<!--
2015-02-23 [296f3a6] Alvaro..: Support more commands in event triggers
-->
        <para>
         Add event trigger support for database-level <link
         linkend="SQL-COMMENT"><command>COMMENT</></>, <link
         linkend="SQL-SECURITY-LABEL"><command>SECURITY LABEL</></>,
         and <link linkend="SQL-GRANT"><command>GRANT</></>/<link
         linkend="SQL-REVOKE"><command>REVOKE</></> (&Aacute;lvaro Herrera)
        </para>
       </listitem>

       <listitem>
<!--
2014-12-30 [72dd233] Alvaro..: pg_event_trigger_dropped_objects: Add name/args..
2015-04-06 [e9a077c] Alvaro..: pg_event_trigger_dropped_objects: add is_temp c..
-->
        <para>
         Add columns to the output of <link
         linkend="pg-event-trigger-sql-drop-functions"><function>pg_event_trigger_dropped_objects</></>
         (&Aacute;lvaro Herrera)
        </para>

        <para>
         This allows simpler processing of delete operations.
        </para>
       </listitem>

      </itemizedlist>

     </sect4>

   </sect3>

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

    <itemizedlist>

     <listitem>
<!--
2014-09-09 [57b1085] Peter ..: Allow empty content in xml type
-->
      <para>
       Allow the <link linkend="datatype-xml"><type>xml</></> data type
       to accept empty or all-whitespace content values (Peter Eisentraut)
      </para>

      <para>
       This is required by the <acronym>SQL</>/<acronym>XML</>
       specification.
      </para>
     </listitem>

     <listitem>
<!--
2014-10-21 [6f04368] Peter ..: Allow input format xxxx-xxxx-xxxx for macaddr ..
-->
      <para>
       Allow <link linkend="datatype-macaddr"><type>macaddr</></> input
       using the format <literal>xxxx-xxxx-xxxx</> (Herwin Weststrate)
      </para>
     </listitem>

     <listitem>
<!--
2014-10-18 [417f924] Bruce ..: interval:  tighten precision specification
-->
      <para>
       Disallow non-SQL-standard syntax for <link
       linkend="datatype-interval-input"><type>interval</></link> with
       both precision and field specifications (Bruce Momjian)
      </para>

      <para>
       Per the standard, such type specifications should be written as,
       for example, <literal>INTERVAL MINUTE TO SECOND(2)</>.
       <productname>PostgreSQL</> formerly allowed this to be written as
       <literal>INTERVAL(2) MINUTE TO SECOND</>, but it must now be
       written in the standard way.
      </para>
     </listitem>

     <listitem>
<!--
2015-04-01 [89840d7] Tom Lane: Provide real selectivity estimators for inet/ci..
-->
      <para>
       Add selectivity estimators for <link
       linkend="datatype-inet"><type>inet</></>/<link
       linkend="datatype-cidr"><type>cidr</></> operators and improve
       estimators for text search functions (Emre Hasegeli, Tom Lane)
      </para>
     </listitem>

     <listitem>
<!--
2015-05-09 [0c90f67] Andrew..: Add new OID alias type regrole
2015-05-09 [cb9fa80] Andrew..: Add new OID alias type regnamespace
-->
      <para>
       Add data
       types <link linkend="datatype-oid-table"><type>regrole</></link>
       and <link linkend="datatype-oid-table"><type>regnamespace</></link>
       to simplify entering and pretty-printing the <type>OID</> of a role
       or namespace (Kyotaro Horiguchi)
      </para>
     </listitem>

    </itemizedlist>

    <sect4>
     <title><link linkend="datatype-json"><acronym>JSON</></link></title>

     <itemizedlist>

      <listitem>
<!--
2015-05-12 [c694701] Andrew..: Additional functions and operators for jsonb
2015-05-31 [37def42] Andrew..: Rename jsonb_replace to jsonb_set and allow it ..
-->
       <para>
        Add <type>jsonb</> functions <link
        linkend="functions-json-processing-table"><function>jsonb_set()</></>
        and <link
        linkend="functions-json-processing-table"><function>jsonb_pretty()</></>
        (Dmitry Dolgov, Andrew Dunstan, Petr Jel&iacute;nek)
       </para>
      </listitem>

      <listitem>
<!--
2014-12-12 [7e354ab] Andrew..: Add several generator functions for jsonb that ..
-->
       <para>
        Add <type>jsonb</> generator functions <link
        linkend="functions-json-creation-table"><function>to_jsonb()</></>,
        <link
        linkend="functions-json-creation-table"><function>jsonb_object()</></>,
        <link
        linkend="functions-json-creation-table"><function>jsonb_build_object()</></>,
        <link
        linkend="functions-json-creation-table"><function>jsonb_build_array()</></>,
        <link
        linkend="functions-aggregate-table"><function>jsonb_agg()</></>,
        and <link
        linkend="functions-aggregate-table"><function>jsonb_object_agg()</></>
        (Andrew Dunstan)
       </para>

       <para>
        Equivalent functions already existed for type <type>json</>.
       </para>
      </listitem>

      <listitem>
<!--
2015-03-03 [b67f1ce] Tom Lane: Reduce json <=> jsonb casts from explicit-only..
-->
       <para>
        Reduce casting requirements to/from <link
        linkend="datatype-json"><type>json</></> and <link
        linkend="datatype-json"><type>jsonb</></> (Tom Lane)
       </para>
      </listitem>

      <listitem>
<!--
2015-06-11 [908e234] Andrew..: Rename jsonb - text[] operator to #- to avoid a..
-->
       <para>
        Allow <type>text</>, <type>text</> array, and <type>integer</>
        values to be <link linkend="functions-jsonb-op-table">subtracted</>
        from <type>jsonb</> documents (Dmitry Dolgov, Andrew Dunstan)
       </para>
      </listitem>

      <listitem>
<!--
2015-05-12 [c694701] Andrew..: Additional functions and operators for jsonb
-->
       <para>
        Add <type>jsonb</> <link
        linkend="functions-jsonb-op-table"><literal>||</></> operator
        (Dmitry Dolgov, Andrew Dunstan)
       </para>
      </listitem>

      <listitem>
<!--
2014-12-12 [237a882] Andrew..: Add json_strip_nulls and jsonb_strip_nulls fun..
-->
       <para>
        Add <link
        linkend="functions-json-processing-table"><function>json_strip_nulls()</></>
        and <link
        linkend="functions-json-processing-table"><function>jsonb_strip_nulls()</></>
        functions to remove JSON null values from documents
        (Andrew Dunstan)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

   <sect3>
    <title>Functions</title>

     <itemizedlist>

      <listitem>
<!--
2014-11-11 [1871c89] Fujii ..: Add generate_series(numeric, numeric).
-->
       <para>
        Add <link linkend="functions-srf"><function>generate_series()</></>
        for <type>numeric</> values (Plato Malugin)
       </para>
      </listitem>

      <listitem>
<!--
2014-11-25 [bac2739] Tom Lane: Support arrays as input to array_agg() and ARRA..
-->
       <para>
        Allow <link
        linkend="functions-aggregate-table"><function>array_agg()</></> and
        <function>ARRAY()</> to take arrays as inputs (Ali Akbar, Tom Lane)
       </para>
      </listitem>

      <listitem>
<!--
2015-03-18 [13dbc7a] Alvaro..: array_offset() and array_offsets()
2015-03-30 [97690ea] Alvaro..: Change array_offset to return subscripts, not o..
-->
       <para>
        Add functions <link
        linkend="array-functions-table"><function>array_position()</></>
        and <link
        linkend="array-functions-table"><function>array_positions()</></>
        to return subscripts of array values (Pavel Stehule)
       </para>
      </listitem>

      <listitem>
<!--
2014-12-15 [4520ba6] Heikki..: Add point <-> polygon distance operator.
-->
       <para>
        Add a <type>point</>-to-<type>polygon</> distance operator
        <link linkend="functions-geometry-op-table">&lt;-&gt;</>
        (Alexander Korotkov)
       </para>
      </listitem>

      <listitem>
<!--
2014-08-27 [8167a38] Jeff D..: Allow multibyte characters as escape in SIMILA..
-->
       <para>
        Allow multibyte characters as escapes in <link
        linkend="functions-similarto-regexp"><literal>SIMILAR TO</></>
        and <link linkend="functions-string-sql"><literal>SUBSTRING</></>
        (Jeff Davis)
       </para>

       <para>
        Previously, only a single-byte character was allowed as an escape.
       </para>
      </listitem>

      <listitem>
<!--
2014-09-09 [e80252d] Tom Lane: Add width_bucket(anyelement, anyarray).
-->
       <para>
        Add a <link
        linkend="functions-math-func-table"><function>width_bucket()</></>
        variant that supports any sortable data type and non-uniform bucket
        widths (Petr Jel&iacute;nek)
       </para>
      </listitem>

      <listitem>
<!--
2015-06-28 [cb2acb1] Heikki..: Add missing_ok option to the SQL functions for..
-->
       <para>
        Add an optional <replaceable>missing_ok</> argument to <link
        linkend="functions-admin-genfile-table"><function>pg_read_file()</></>
        and related functions (Michael Paquier, Heikki Linnakangas)
       </para>
      </listitem>

      <listitem>
<!--
2015-03-10 [865f14a] Robert..: Allow named parameters to be specified using =>..
-->
       <para>
        Allow <link linkend="sql-syntax-calling-funcs"><literal>=&gt;</></>
        to specify named parameters in function calls (Pavel Stehule)
       </para>

       <para>
        Previously only <literal>:=</> could be used.  This requires removing
        the possibility for <literal>=&gt;</> to be a user-defined operator.
        Creation of user-defined <literal>=&gt;</> operators has been issuing
        warnings since PostgreSQL 9.0.
       </para>
      </listitem>

      <listitem>
<!--
2015-03-25 [06bf0dd] Tom Lane: Upgrade src/port/rint.c to be POSIX-compliant.
-->
       <para>
        Add <acronym>POSIX</>-compliant rounding for platforms that use
        PostgreSQL-supplied rounding functions (Pedro Gimeno Fortea)
       </para>
      </listitem>

     </itemizedlist>

    <sect4>
     <title>System Information Functions and Views</title>

     <itemizedlist>

      <listitem>
<!--
2014-12-23 [d7ee82e] Alvaro..: Add SQL-callable pg_get_object_address
2014-12-30 [a676201] Alvaro..: Add pg_identify_object_as_address
-->
       <para>
        Add function <link
        linkend="functions-info-object-table"><function>pg_get_object_address()</></>
        to return <type>OID</>s that uniquely
        identify an object, and function <link
        linkend="functions-info-object-table"><function>pg_identify_object_as_address()</></>
        to return object information based on <type>OID</>s (&Aacute;lvaro
        Herrera)
       </para>
      </listitem>

      <listitem>
<!--
2015-03-19 [bf03889] Stephe..: GetUserId() changes to has_privs_of_role()
-->
       <para>
        Loosen security checks for viewing queries in <link
        linkend="pg-stat-activity-view"><structname>pg_stat_activity</></>,
        executing <link
        linkend="functions-admin-signal-table"><function>pg_cancel_backend()</></>,
        and executing <link
        linkend="functions-admin-signal-table"><function>pg_terminate_backend()</></>
        (Stephen Frost)
       </para>

       <para>
        Previously, only the specific role owning the target session could
        perform these operations; now membership in that role is sufficient.
       </para>
      </listitem>

      <listitem>
<!--
2015-02-19 [2fb7a75] Tom Lane: Add pg_stat_get_snapshot_timestamp() to show s..
-->
       <para>
        Add <link
        linkend="monitoring-stats-funcs-table"><function>pg_stat_get_snapshot_timestamp()</></>
        to output the time stamp of the statistics snapshot (Matt Kelly)
       </para>

       <para>
        This represents the last time the snapshot file was written to
        the file system.
       </para>
      </listitem>

      <listitem>
<!--
2014-09-10 [36ad1a8] Bruce ..: Implement mxid_age() to compute multi-xid age
-->
       <para>
        Add <link
        linkend="vacuum-for-multixact-wraparound"><function>mxid_age()</></>
        to compute multi-xid age (Bruce Momjian)
       </para>
      </listitem>
     </itemizedlist>

    </sect4>

    <sect4>
     <title>Aggregates</title>

     <itemizedlist>

      <listitem>
<!--
2014-08-28 [6c40f83] Tom Lane: Add min and max aggregates for inet/cidr data t..
-->
       <para>
        Add <function>min()</>/<function>max()</> aggregates
        for <link linkend="datatype-inet"><type>inet</></>/<link
        linkend="datatype-cidr"><type>cidr</></> data types (Haribabu
        Kommi)
       </para>
      </listitem>

      <listitem>
<!--
2015-03-20 [8122e14] Andres..: Add, optional, support for 128bit integers.
2015-03-20 [959277a] Andres..: Use 128-bit math to accelerate some aggregation..
-->
       <para>
        Use 128-bit integers, where supported, as accumulators for some
        aggregate functions (Andreas Karlsson)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

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

    <itemizedlist>

     <listitem>
<!--
2014-07-03 [8b6010b] Tom Lane: Improve support for composite types in PL/Python.
-->
      <para>
       Improve support for composite types in <link
       linkend="plpython"><application>PL/Python</></> (Ed Behn, Ronan
       Dunklau)
      </para>

      <para>
       This allows <application>PL/Python</> functions to return arrays
       of composite types.
      </para>
     </listitem>

     <listitem>
<!--
2015-03-11 [1ce7a57] Peter ..: PL/Python: Avoid lossiness in float conversion
-->
      <para>
       Reduce lossiness of <link
       linkend="plpython"><application>PL/Python</></> floating-point value
       conversions (Marko Kreen)
      </para>
     </listitem>

     <listitem>
<!--
2015-04-26 [cac7658] Peter ..: Add transforms feature
-->
      <para>
       Allow specification of conversion routines between <acronym>SQL</>
       data types and data types of procedural languages (Peter Eisentraut)
      </para>

      <para>
       This change adds new commands <link
       linkend="SQL-CREATETRANSFORM"><command>CREATE</></>/<link
       linkend="SQL-DROPTRANSFORM"><command>DROP TRANSFORM</></>.
       This also adds optional transformations between the <link
       linkend="hstore"><application>hstore</></> and <link
       linkend="ltree"><application>ltree</></> types to/from <link
       linkend="plperl"><application>PL/Perl</></> and <link
       linkend="plpython"><application>PL/Python</></>.
      </para>
     </listitem>

     </itemizedlist>

     <sect4>
      <title><link linkend="plpgsql">PL/pgSQL</link> Server-Side Language</title>

      <itemizedlist>

     <listitem>
<!--
2015-05-14 [1dc5ebc] Tom Lane: Support "expanded" objects, particularly arrays..
2015-02-16 [e983c4d] Tom Lane: Rationalize the APIs of array element/slice acc..
2015-02-18 [56a79a8] Tom Lane: Split array_push into separate array_append and..
2015-02-16 [9e3ad1a] Tom Lane: Use fast path in plpgsql's RETURN/RETURN NEXT i..
-->
      <para>
       Improve <link linkend="plpgsql"><application>PL/pgSQL</></> array
       performance (Tom Lane)
      </para>
     </listitem>

     <listitem>
<!--
2015-03-25 [a4847fc] Tom Lane: Add an ASSERT statement in plpgsql.
-->
      <para>
       Add an <link linkend="plpgsql-statements-assert"><command>ASSERT</></>
       statement in <application>PL/pgSQL</> (Pavel Stehule)
      </para>
     </listitem>

     <listitem>
<!--
2014-11-25 [bb1b8f6] Tom Lane: De-reserve most statement-introducing keywords ..
-->
      <para>
       Allow more <link linkend="plpgsql"><application>PL/pgSQL</></>
       keywords to be used as identifiers (Tom Lane)
      </para>
     </listitem>

    </itemizedlist>

    </sect4>

   </sect3>

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

    <itemizedlist>

     <listitem>
<!--
2015-04-11 [83aca89] Peter ..: Move pg_archivecleanup from contrib/ to src/bin/
2015-04-19 [00882d9] Peter ..: Move pg_test_fsync from contrib/ to src/bin/
2015-04-20 [528c2e4] Peter ..: Move pg_test_timing from contrib/ to src/bin/
2015-04-21 [b0a738f] Peter ..: Move pg_xlogdump from contrib/ to src/bin/
-->
      <para>
       Move <link
       linkend="pgarchivecleanup"><application>pg_archivecleanup</></>,
       <link linkend="pgtestfsync"><application>pg_test_fsync</></>,
       <link linkend="pgtesttiming"><application>pg_test_timing</></>,
       and <link linkend="pgxlogdump"><application>pg_xlogdump</></>
       from <filename>contrib</> to <filename>src/bin</> (Peter Eisentraut)
      </para>

      <para>
       This should result in these programs being installed by default in
       most installations.
      </para>
     </listitem>

     <listitem>
<!--
2015-03-23 [61081e7] Heikki..: Add pg_rewind, for re-synchronizing a master se..
-->
      <para>
       Add <link linkend="app-pgrewind"><application>pg_rewind</></>,
       which allows re-synchronizing a master server after failback
       (Heikki Linnakangas)
      </para>
     </listitem>

     <listitem>
<!--
2014-10-06 [d9f38c7] Andres..: Add support for managing physical replication s..
-->
      <para>
       Allow <link
       linkend="app-pgreceivexlog"><application>pg_receivexlog</></>
       to manage physical replication slots (Michael Paquier)
      </para>

      <para>
       This is controlled via new <option>--create-slot</> and
       <option>--drop-slot</> options.
      </para>
     </listitem>

     <listitem>
<!--
2014-11-18 [c4f99d2] Fujii ..: Add &#8211;&#8211;synchronous option to pg_receivexlog, for..
-->
      <para>
       Allow <link
       linkend="app-pgreceivexlog"><application>pg_receivexlog</></>
       to synchronously flush <acronym>WAL</> to storage using new
       <option>--synchronous</> option (Furuya Osamu, Fujii Masao)
      </para>

      <para>
       Without this, <acronym>WAL</> files are fsync'ed only on close.
      </para>
     </listitem>

     <listitem>
<!--
2015-01-23 [a179232] Alvaro..: vacuumdb: enable parallel mode
-->
      <para>
       Allow <link linkend="APP-VACUUMDB"><application>vacuumdb</></> to
       vacuum in parallel using new <option>--jobs</> option (Dilip Kumar)
      </para>
     </listitem>

     <listitem>
<!--
2015-11-12 [5094da9] Alvaro..: vacuumdb: don't prompt for passwords over and ..
-->
      <para>
       In <link linkend="APP-VACUUMDB"><application>vacuumdb</></>, do not
       prompt for the same password repeatedly when multiple connections
       are necessary (Haribabu Kommi, Michael Paquier)
      </para>
     </listitem>

     <listitem>
<!--
2015-05-15 [458a077] Fujii ..: Support &#8211;&#8211;verbose option in reindexdb.
-->
      <para>
       Add <option>--verbose</> option to <link
       linkend="APP-REINDEXDB"><application>reindexdb</></> (Sawada
       Masahiko)
      </para>
     </listitem>

     <listitem>
<!--
2015-05-12 [72d422a] Andrew..: Map basebackup tablespaces using a tablespace_..
-->
      <para>
       Make <link linkend="app-pgbasebackup"><application>pg_basebackup</></>
       use a tablespace mapping file when using <application>tar</> format,
       to support symbolic links and file paths of 100+ characters in length
       on <systemitem class="osname">MS Windows</> (Amit Kapila)
      </para>
     </listitem>

     <listitem>
<!--
2014-09-19 [728f152] Andres..: Add rmgr callback to name xlog record types for..
2014-09-19 [bdd5726] Andres..: Add the capability to display summary statistic..
-->
      <para>
       Add <link linkend="pgxlogdump"><application>pg_xlogdump</></> option
       <option>--stats</> to display summary statistics (Abhijit Menon-Sen)
      </para>
     </listitem>

    </itemizedlist>

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

      <itemizedlist>

       <listitem>
<!--
2015-03-31 [9d9991c] Bruce ..: psql:  add asciidoc output format
-->
        <para>
         Allow <application>psql</> to produce AsciiDoc output (Szymon Guz)
        </para>
       </listitem>

       <listitem>
<!--
2014-07-10 [5b214c5] Fujii ..: Add new ECHO mode 'errors' that displays only ..
-->
        <para>
         Add an <literal>errors</> mode that displays only failed commands
         to <application>psql</>'s <varname>ECHO</> variable
         (Pavel Stehule)
        </para>

        <para>
         This behavior can also be selected with <application>psql</>'s
         <option>-b</> option.
        </para>
       </listitem>

       <listitem>
<!--
2014-09-12 [a2dabf0] Stephe..: Add unicode_{column|header|border}_style to psql
-->
        <para>
         Provide separate column, header, and border linestyle control
         in <application>psql</>'s unicode linestyle (Pavel Stehule)
        </para>

        <para>
         Single or double lines are supported; the default is
         <literal>single</>.
        </para>
       </listitem>

       <listitem>
<!--
2014-09-02 [51bb795] Andres..: Add psql PROMPT variable showing which line of ..
-->
        <para>
         Add new option <literal>%l</> in <application>psql</>'s <link
         linkend="APP-PSQL-variables"><envar>PROMPT</></> variables
         to display the current multiline statement line number
         (Sawada Masahiko)
        </para>
       </listitem>

       <listitem>
<!--
2015-03-28 [7655f4c] Andrew..: Add a pager_min_lines setting to psql
-->
        <para>
         Add <literal>\pset</> option <link
         linkend="APP-PSQL-meta-commands"><varname>pager_min_lines</></>
         to control pager invocation (Andrew Dunstan)
        </para>
       </listitem>

       <listitem>
<!--
2014-11-21 [4077fb4] Andrew..: Fix an error in psql that overcounted output l..
-->
        <para>
         Improve <application>psql</> line counting used when deciding
         to invoke the pager (Andrew Dunstan)
        </para>
       </listitem>

       <listitem>
<!--
2015-12-03 [07338cb] Tom Lane: Clean up some psql issues around handling of t..
2015-12-08 [e90371d] Tom Lane: Make failure to open psql log-file fatal.
-->
        <para>
         <application>psql</> now fails if the file specified by
         an <option>--output</> or <option>--log-file</> switch cannot be
         written (Tom Lane, Daniel Verite)
        </para>

        <para>
         Previously, it effectively ignored the switch in such cases.
        </para>
       </listitem>

       <listitem>
<!--
2014-07-12 [bd40951] Andres..: Minimal psql tab completion support for SET se..
-->
        <para>
         Add <application>psql</> tab completion when setting the
         <xref linkend="guc-search-path"> variable (Jeff Janes)
        </para>

        <para>
         Currently only the first schema can be tab-completed.
        </para>
       </listitem>

       <listitem>
<!--
2014-06-23 [631e7f6] Heikki..: Improve tab-completion of DROP and ALTER ENABLE..
-->
        <para>
         Improve <application>psql</>'s tab completion for triggers and rules
         (Andreas Karlsson)
        </para>
       </listitem>

      </itemizedlist>

     <sect5>
      <title><link linkend="APP-PSQL-meta-commands">Backslash Commands</link></title>

      <itemizedlist>

       <listitem>
<!--
2014-09-10 [07c8651] Andres..: Add new psql help topics, accessible to both..
-->
        <para>
         Add <application>psql</> <command>\?</> help sections
         <literal>variables</> and <literal>options</> (Pavel Stehule)
        </para>

        <para>
         <literal>\? variables</> shows <application>psql</>'s special
         variables and <literal>\? options</> shows the command-line options.
         <command>\? commands</> shows the meta-commands, which is the
         traditional output and remains the default.  These help displays
         can also be obtained with the command-line
         option <literal>--help=<replaceable>section</></literal>.
        </para>
       </listitem>

       <listitem>
<!--
2014-07-14 [ee80f04] Alvaro..: psql: Show tablespace size in \db+
-->
        <para>
         Show tablespace size in <application>psql</>'s <literal>\db+</>
         (Fabr&iacute;zio de Royes Mello)
        </para>
       </listitem>

       <listitem>
<!--
2015-04-09 [a6f3c1f] Magnus..: Show owner of types in psql \dT+
-->
        <para>
         Show data type owners in <application>psql</>'s <literal>\dT+</>
         (Magnus Hagander)
        </para>
       </listitem>

       <listitem>
<!--
2014-09-04 [f6f654f] Fujii ..: Allow \watch to display query execution time if..
-->
        <para>
         Allow <application>psql</>'s <command>\watch</> to output
         <command>\timing</> information (Fujii Masao)
        </para>

        <para>
         Also prevent <option>--echo-hidden</> from echoing
         <command>\watch</> queries, since that is generally unwanted.
        </para>
       </listitem>

       <listitem>
<!--
2014-11-22 [eca2b9b] Andrew..: Rework echo_hidden for \sf and \ef from commit ..
-->
        <para>
         Make <application>psql</>'s <literal>\sf</> and <literal>\ef</>
         commands honor <envar>ECHO_HIDDEN</> (Andrew Dunstan)
        </para>
       </listitem>

       <listitem>
<!--
2014-08-12 [e15c4ab] Fujii ..: Add tab-completion for \unset and valid setting..
-->
        <para>
         Improve <application>psql</> tab completion for <command>\set</>,
         <command>\unset</>, and <literal>:variable</> names (Pavel
         Stehule)
        </para>
       </listitem>

       <listitem>
<!--
2014-11-10 [095d401] Robert..: Tab complete second argument to \c with role n..
-->
        <para>
         Allow tab completion of role names
         in <application>psql</> <literal>\c</> commands (Ian Barwick)
        </para>
       </listitem>

      </itemizedlist>

     </sect5>

    </sect4>

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

     <itemizedlist>

      <listitem>
<!--
2014-11-17 [be1cc8f] Simon ..: Add pg_dump &#8211;&#8211;snapshot option
-->
       <para>
        Allow <application>pg_dump</> to share a snapshot taken by another
        session using <option>--snapshot</> (Simon Riggs, Michael Paquier)
       </para>

       <para>
        The remote snapshot must have been exported by
        <function>pg_export_snapshot()</> or logical replication slot
        creation.  This can be used to share a consistent snapshot
        across multiple <application>pg_dump</> processes.
       </para>
      </listitem>

      <listitem>
<!--
2015-11-21 [5f5e68b] Tom Lane: Adopt the GNU convention for handling tar-arch..
-->
       <para>
        Support table sizes exceeding 8GB in tar archive format (Tom Lane)
       </para>

       <para>
        The POSIX standard for tar format does not allow elements of a tar
        archive to exceed 8GB, but most modern implementations of tar
        support an extension that does allow it.  Use the extension format
        when necessary, rather than failing.
       </para>
      </listitem>

      <listitem>
<!--
2014-07-07 [7700597] Tom Lane: In pg_dump, show server and pg_dump versions w..
-->
       <para>
        Make <application>pg_dump</> always print the server and
        <application>pg_dump</> versions (Jing Wang)
       </para>

       <para>
        Previously, version information was only printed in
        <option>--verbose</> mode.
       </para>
      </listitem>

      <listitem>
<!--
2015-06-04 [232cd63] Fujii ..: Remove -i/-ignore-version option from pg_dump..
-->
       <para>
        Remove the long-ignored <option>-i</>/<option>--ignore-version</>
        option from <application>pg_dump</>, <application>pg_dumpall</>,
        and <application>pg_restore</> (Fujii Masao)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

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

     <itemizedlist>

      <listitem>
<!--
2014-08-25 [ebe30ad] Bruce ..: pg_ctl, pg_upgrade:  allow multiple -o/-O opti..
-->
       <para>
        Support multiple <application>pg_ctl</> <option>-o</> options,
        concatenating their values (Bruce Momjian)
       </para>
      </listitem>

      <listitem>
<!--
2014-07-17 [c0e4520] Magnus..: Add option to pg_ctl to choose event source for..
-->
       <para>
        Allow control of <application>pg_ctl</>'s event source logging
        on <systemitem class="osname">MS Windows</> (MauMau)
       </para>

       <para>
        This only controls <application>pg_ctl</>, not the server, which
        has separate settings in <filename>postgresql.conf</>.
       </para>
      </listitem>

      <listitem>
<!--
2015-11-08 [bdb42ba] Noah M..: Don't connect() to a wildcard address in test_..
-->
       <para>
        If the server's listen address is set to a wildcard value
        (<literal>0.0.0.0</> in IPv4 or <literal>::</> in IPv6), connect via
        the loopback address rather than trying to use the wildcard address
        literally (Kondo Yuta)
       </para>

       <para>
        This fix primarily affects Windows, since on other platforms
        <application>pg_ctl</> will prefer to use a Unix-domain socket.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

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

     <itemizedlist>

      <listitem>
<!--
2015-04-14 [9fa8b0e] Peter ..: Move pg_upgrade from contrib/ to src/bin/
-->
       <para>
        Move <application>pg_upgrade</> from <filename>contrib</> to
        <filename>src/bin</> (Peter Eisentraut)
       </para>

       <para>
        In connection with this change, the functionality previously
        provided by the <application>pg_upgrade_support</> module has been
        moved into the core server.
       </para>
      </listitem>

      <listitem>
<!--
2014-08-25 [ebe30ad] Bruce ..: pg_ctl, pg_upgrade:  allow multiple -o/-O optio..
-->
       <para>
        Support multiple <application>pg_upgrade</>
        <option>-o</>/<option>-O</> options,
        concatenating their values (Bruce Momjian)
       </para>
      </listitem>

      <listitem>
<!--
2014-10-10 [33755e8] Heikki..: Change the way encoding and locale checks are d..
-->
       <para>
        Improve database collation comparisons in
        <application>pg_upgrade</> (Heikki Linnakangas)
       </para>
      </listitem>

      <listitem>
<!--
2014-08-25 [2209b39] Bruce ..: pg_upgrade:  remove support for 8.3 old clusters
-->
       <para>
        Remove support for upgrading from 8.3 clusters (Bruce Momjian)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

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

     <itemizedlist>

      <listitem>
<!--
2015-04-13 [81134af] Peter ..: Move pgbench from contrib/ to src/bin/
-->
       <para>
        Move pgbench from <filename>contrib</> to <filename>src/bin</>
        (Peter Eisentraut)
       </para>
      </listitem>

      <listitem>
<!--
2015-09-30 [3c4c5ac] Tatsuo..: Fix incorrect tps number calculation in "exclu..
-->
       <para>
        Fix calculation of TPS number <quote>excluding connections
        establishing</> (Tatsuo Ishii, Fabien Coelho)
       </para>

       <para>
        The overhead for connection establishment was miscalculated whenever
        the number of pgbench threads was less than the number of client
        connections.  Although this is clearly a bug, we won't back-patch it
        into pre-9.5 branches since it makes TPS numbers not comparable to
        previous results.
       </para>
      </listitem>

      <listitem>
<!--
2014-10-13 [98aed6c] Heikki..: Add &#8211;&#8211;latency-limit option to pgbench.
-->
       <para>
        Allow counting of pgbench transactions that take over a specified
        amount of time (Fabien Coelho)
       </para>

       <para>
        This is controlled by a new <option>--latency-limit</> option.
       </para>
      </listitem>

      <listitem>
<!--
2014-07-30 [ed802e7] Robert..: pgbench: Allow \setrandom to generate Gaussian..
-->
       <para>
        Allow pgbench to generate Gaussian/exponential distributions
        using <command>\setrandom</> (Kondo Mitsumasa, Fabien Coelho)
       </para>
      </listitem>

      <listitem>
<!--
2015-03-02 [878fdcb] Robert..: pgbench: Add a real expression syntax to \set
-->
       <para>
        Allow <application>pgbench</>'s <command>\set</> command to handle
        arithmetic expressions containing more than one operator, and add
        <literal>%</> (modulo) to the set of operators it supports
        (Robert Haas, Fabien Coelho)
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

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

     <itemizedlist>

      <listitem>
<!--
2014-11-20 [2c03216] Heikki..: Revamp the WAL record format.
-->
       <para>
        Simplify <link linkend="wal"><acronym>WAL</></> record format
        (Heikki Linnakangas)
       </para>

       <para>
        This allows external tools to more easily track what blocks
        are modified.
       </para>
      </listitem>

      <listitem>
<!--
2015-03-15 [4f1b890] Andres..: Merge the various forms of transaction commit &..
-->
       <para>
        Improve the representation of transaction commit and abort WAL
        records (Andres Freund)
       </para>
      </listitem>

      <listitem>
<!--
2014-09-25 [b64d92f] Andres..: Add a basic atomic ops API abstracting away pla..
-->
       <para>
        Add atomic memory operations <acronym>API</> (Andres Freund)
       </para>
      </listitem>

      <listitem>
<!--
2014-11-07 [0b03e59] Robert..: Introduce custom path and scan providers.
2014-11-20 [a34fa8e] Tom Lane: Initial code review for CustomScan patch.
2014-11-21 [c2ea228] Tom Lane: Simplify API for initially hooking custom-path ..
2014-11-21 [4477704] Tom Lane: Rearrange CustomScan API.
-->
       <para>
        Allow custom path and scan methods (KaiGai Kohei, Tom Lane)
       </para>

       <para>
        This allows extensions greater control over the optimizer and
        executor.
       </para>
      </listitem>

      <listitem>
<!--
2015-05-12 [afb9249] Tom Lane: Add support for doing late row locking in FDWs.
-->
       <para>
        Allow foreign data wrappers to do post-filter locking (Etsuro
        Fujita)
       </para>
      </listitem>

      <listitem>
<!--
2015-05-08 [168d580] Andres..: Add support for INSERT ... ON CONFLICT DO NOTHI..
2015-05-08 [2c8f483] Andres..: Represent columns requiring insert and update p..
-->
       <para>
        Foreign tables can now take part in <command>INSERT ... ON CONFLICT
        DO NOTHING</> queries (Peter Geoghegan, Heikki Linnakangas,
        Andres Freund)
       </para>

       <para>
        Foreign data wrappers must be modified to handle this.
        <command>INSERT ... ON CONFLICT DO UPDATE</> is not supported on
        foreign tables.
       </para>
      </listitem>

      <listitem>
<!--
2014-12-18 [4a14f13] Tom Lane: Improve hash_create's API for selecting simple-..
-->
       <para>
        Improve <function>hash_create()</>'s API for selecting
        simple-binary-key hash functions (Teodor Sigaev, Tom Lane)
       </para>
      </listitem>

      <listitem>
<!--
2015-04-30 [924bcf4] Robert..: Create an infrastructure for parallel computati..
2014-10-31 [2bd9e41] Robert..: Support frontend-backend protocol communication..
-->
       <para>
        Improve parallel execution infrastructure (Robert Haas, Amit
        Kapila, Noah Misch, Rushabh Lathia, Jeevan Chalke)
       </para>
      </listitem>

      <listitem>
<!--
2014-06-28 [a6d488c] Andres..: Remove Alpha and Tru64 support.
-->
       <para>
        Remove <productname>Alpha</> (<acronym>CPU</>) and <systemitem
        class="osname">Tru64</> (OS) ports (Andres Freund)
       </para>
      </listitem>

      <listitem>
<!--
2014-07-06 [4893ccd] Robert..: Remove swpb-based spinlock implementation for A..
-->
       <para>
        Remove swap-byte-based spinlock implementation for
        <acronym>ARM</>v5 and earlier <acronym>CPU</>s (Robert Haas)
       </para>

       <para>
        <acronym>ARM</>v5's weak memory ordering made this locking
        implementation unsafe.  Spinlock support is still possible on
        newer gcc implementations with atomics support.
       </para>
      </listitem>

      <listitem>
<!--
2015-02-24 [23a7835] Peter ..: Error when creating names too long for tar for..
-->
       <para>
        Generate an error when excessively long (100+ character) file
        paths are written to tar files (Peter Eisentraut)
       </para>

       <para>
        Tar does not support such overly-long paths.
       </para>
      </listitem>

      <listitem>
<!--
2015-05-19 [0b28ea7] Tom Lane: Avoid collation dependence in indexes of syste..
-->
       <para>
        Change index operator class for columns <link
        linkend="catalog-pg-seclabel"><structname>pg_seclabel</></>.<structname>provider</>
        and <link
        linkend="catalog-pg-shseclabel"><structname>pg_shseclabel</></>.<structname>provider</>
        to be <literal>text_pattern_ops</> (Tom Lane)
       </para>

       <para>
        This avoids possible problems with these indexes when different
        databases of a cluster have different default collations.
       </para>
      </listitem>

      <listitem>
<!--
2014-09-09 [0709b7e] Robert..: Change the spinlock primitives to function as c..
-->
       <para>
        Change the spinlock primitives to function as compiler barriers
        (Robert Haas)
       </para>
      </listitem>

     </itemizedlist>

    <sect4>
     <title>MS Windows</title>

     <itemizedlist>

      <listitem>
<!--
2014-12-08 [519b075] Simon ..: Use GetSystemTimeAsFileTime directly in win32
2014-12-08 [8001fe6] Simon ..: Windows: use GetSystemTimePreciseAsFileTime if ..
-->
       <para>
        Allow higher-precision time stamp resolution on <systemitem
        class="osname">Windows 8</>, <systemitem class="osname">Windows
        Server 2012</>, and later Windows systems (Craig Ringer)
       </para>
      </listitem>

      <listitem>
<!--
2015-03-18 [f9dead5] Alvaro..: Install shared libraries to bin/ in Windows un..
-->
       <para>
        Install shared libraries to <filename>bin</> in <systemitem
        class="osname">MS Windows</> (Peter Eisentraut, Michael Paquier)
       </para>
      </listitem>

      <listitem>
<!--
2015-04-16 [22d0053] Alvaro..: MSVC: install src/test/modules together with c..
-->
       <para>
        Install <filename>src/test/modules</> together with
        <filename>contrib</> on <productname>MSVC</> builds (Michael
        Paquier)
       </para>
      </listitem>

      <listitem>
<!--
2014-07-12 [8d9a0e8] Magnus..: Support &#8211;&#8211;with-extra-version equivalent functi..
-->
       <para>
        Allow <link linkend="install-procedure">configure</>'s
        <option>--with-extra-version</> option to be honored by the
        <productname>MSVC</> build (Michael Paquier)
       </para>
      </listitem>

      <listitem>
<!--
2014-07-14 [91f03ba] Noah M..: MSVC: Recognize PGFILEDESC in contrib and conv..
-->
       <para>
        Pass <envar>PGFILEDESC</> into <productname>MSVC</> contrib builds
        (Michael Paquier)
       </para>
      </listitem>

      <listitem>
<!--
2014-07-14 [c4a448e] Noah M..: MSVC: Apply icons to all binaries having them ..
-->
       <para>
        Add icons to all <productname>MSVC</>-built binaries and version
        information to all <systemitem class="osname">MS Windows</>
        binaries (Noah Misch)
       </para>

       <para>
        MinGW already had such icons.
       </para>
      </listitem>

      <listitem>
<!--
2014-09-10 [311da16] Andres..: Add support for optional_argument to our own ge..
-->
       <para>
        Add optional-argument support to the internal
        <function>getopt_long()</> implementation (Michael Paquier,
        Andres Freund)
       </para>

       <para>
        This is used by the <productname>MSVC</> build.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

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

    <itemizedlist>

     <listitem>
<!--
2015-03-27 [717f709] Andrew..: Add stats for min, max, mean, stddev times to p..
-->
      <para>
       Add statistics for minimum, maximum,
       mean, and standard deviation times to <link
       linkend="pgstatstatements-columns"><application>pg_stat_statements</></>
       (Mitsumasa Kondo, Andrew Dunstan)
      </para>
     </listitem>

     <listitem>
<!--
2014-10-01 [32984d8] Heikki..: Add functions for dealing with PGP armor heade..
-->
      <para>
       Add <link linkend="pgcrypto"><application>pgcrypto</></> function
       <function>pgp_armor_headers()</> to extract <productname>PGP</>
       armor headers (Marko Tiikkaja, Heikki Linnakangas)
      </para>
     </listitem>

     <listitem>
<!--
2014-06-30 [97c40ce] Tom Lane: Allow empty replacement strings in contrib/unac..
-->
      <para>
       Allow empty replacement strings in <link
       linkend="unaccent"><application>unaccent</></> (Mohammad Alhashash)
      </para>

      <para>
       This is useful in languages where diacritic signs are represented
       as separate characters.
      </para>
     </listitem>

     <listitem>
<!--
2014-06-30 [1b24887] Tom Lane: Allow multi-character source strings in contrib..
-->
      <para>
       Allow multicharacter source strings in <link
       linkend="unaccent"><application>unaccent</></> (Tom Lane)
      </para>

      <para>
       This could be useful in languages where diacritic signs are
       represented as separate characters.  It also allows more complex
       unaccent dictionaries.
      </para>
     </listitem>

     <listitem>
<!--
2015-05-15 [9689290] Simon ..: TABLESAMPLE system_rows(limit)
2015-05-15 [149f6f1] Simon ..: TABLESAMPLE system_time(limit)
-->
      <para>
       Add <filename>contrib</> modules <link
       linkend="tsm-system-rows"><application>tsm_system_rows</></> and
       <link linkend="tsm-system-time"><application>tsm_system_time</></>
       to allow additional table sampling methods (Petr Jel&iacute;nek)
      </para>
     </listitem>

     <listitem>
<!--
2014-11-21 [3a82bc6] Heikki..: Add pageinspect functions for inspecting GIN in..
-->
      <para>
       Add <link linkend="GIN"><acronym>GIN</></>
       index inspection functions to <link
       linkend="pageinspect"><application>pageinspect</></> (Heikki
       Linnakangas, Peter Geoghegan, Michael Paquier)
      </para>
     </listitem>

     <listitem>
<!--
2014-08-22 [f577919] Andres..: Add pinning_backends column to the pg_buffercac..
-->
      <para>
       Add information about buffer pins to <link
       linkend="pgbuffercache"><application>pg_buffercache</></> display
       (Andres Freund)
      </para>
     </listitem>

     <listitem>
<!--
2015-05-13 [5850b20] Andres..: Add pgstattuple_approx() to the pgstattuple ext..
-->
      <para>
       Allow <link linkend="pgstattuple"><application>pgstattuple</></>
       to report approximate answers with less overhead using
       <function>pgstattuple_approx()</> (Abhijit Menon-Sen)
      </para>
     </listitem>

     <listitem>
<!--
2014-11-29 [22dfd11] Alvaro..: Move test modules from contrib to src/test/modu..
2014-12-01 [df761e3] Alvaro..: Move security_label test
-->
      <para>
       Move <application>dummy_seclabel</>, <application>test_shm_mq</>,
       <application>test_parser</>, and <application>worker_spi</>
       from <filename>contrib</> to <filename>src/test/modules</>
       (&Aacute;lvaro Herrera)
      </para>

      <para>
       These modules are only meant for server testing, so they do not need
       to be built or installed when packaging <productname>PostgreSQL</>.
      </para>
     </listitem>

    </itemizedlist>

   </sect3>

  </sect2>

 </sect1>