postgresql/doc/src/sgml/release-9.5.sgml

<!-- doc/src/sgml/release-9.5.sgml -->
<!-- See header comment in release.sgml about typical markup -->

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

  <note>
   <title>Release Date</title>
   <simpara>2015-??-??</simpara>
   <simpara>Current as of 2015-10-03</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>
      ... to be filled in ...
     </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>
<!--
2015-03-11 [c6b3c93] Tom Lane: Make operator precedence follow the SQL standar..
-->
     <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>
<!--
2015-03-31 [0badb06] Bruce ..: pg_ctl:  change default shutdown mode from 'sma..
-->
     <para>
      Change <application>pg_ctl</>'s default shutdown mode from
      <literal>smart</> to <literal>fast</> (Bruce Momjian)
     </para>
    </listitem>

    <listitem>
<!--
2015-03-04 [1345cc6] Tom Lane: Use standard casting mechanism to convert type..
-->
     <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>
<!--
2014-08-28 [11a020e] Andres..: Allow escaping of option values for options pas..
-->
     <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>
<!--
2015-05-08 [9a08841] Stephe..: Change default for include_realm to 1
-->
     <para>
      Change the default value of <link
      linkend="gssapi-auth"><varname>include_realm</></> 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>
<!--
2015-01-22 [59367fd] Bruce ..: adjust ACL owners for REASSIGN and ALTER OWNER..
-->
     <para>
      Fix <link linkend="SQL-REASSIGN-OWNED"><command>REASSIGN OWNED</></>
      and <link linkend="SQL-ALTERTYPE"><command>ALTER OWNER TO</></>
      to properly update permissions lists (ACLs) when changing ownership of
      types, foreign data wrappers, and foreign servers (Bruce Momjian)
     </para>
    </listitem>

    <listitem>
     <para>
      The configuration parameter <varname>checkpoint_segments</varname> has
      been removed.  Its place is taken by the new
      setting <xref linkend="guc-max-wal-size">.  If you had previously
      tuned <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 setting this might no longer be necessary.
     </para>
    </listitem>

    <listitem>
<!--
2015-07-28 [6087d95] Andres..: Remove ssl renegotiation support.
-->
     <para>
      Remove 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</>.
     </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 <link linkend="catalog-pg-authid"><structname>pg_authid</></>'s
      <structfield>rolcatupdate</> field, as it had no value (Adam Brightwell)
     </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.
      Previously, these operators returned <literal>NULL</> for negative
      subscripts.  (Peter Geoghegan, Andrew Dunstan)
     </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 are very compact and cheap to update by
        storing min/max values for a range of heap blocks.
       </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, a common table expression was required to return a
        large number of rows ordered by bounding-box distance, and then
        filtered further with a more accurate non-bounding-box 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>
        Previously the list size was controlled
        by <xref linkend="guc-work-mem">.  This can also be set as an index
        storage parameter.
       </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 <type>VARCHAR</>, <type>TEXT</>,
        and <type>NUMERIC</> fields (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..
FIXME: bad description? Should talk about hash joins
-->
       <para>
        Improve in-memory hash performance (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.
FIXME: Add Andres
-->
       <para>
        Improve concurrency of shared buffer replacement
        (Robert Haas, Amit Kapila)
       </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 backend local tracking of buffer pins memory efficient (Andres Freund)
       </para>

       <para>
        Previously each session allocated an array with space for every buffer
        in <link linkend="guc-shared-buffers"><varname>shared_buffers</></link>.
       </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
        outer join 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 <link
        linkend="functions-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 non-leakproof functions to be passed into security barrier
        views if the function does not reference any table 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>
       <para>
<!--
2014-07-01 [9f03ca9] Robert..: Avoid copying index tuples when building an ind..
-->
        Speed up CREATE INDEX by avoiding unnecessary memory copies (Robert Haas)
       </para>
      </listitem>

      <listitem>
       <para>
<!--
2014-10-02 [3acc10c9] Robert..: Increase the number of buffer mapping partitio..
-->
        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
        <varname>log_min_autovacuum_duration</> (Michael Paquier)
       </para>

       <para>
        NOT DOCUMENTED?
       </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</> function <link
        linkend="libpq-pqsslAttribute"><function>PQsslAttribute()</></>
        that returns <acronym>SSL</> information (Heikki Linnakangas)
       </para>

       <para>
        While <link linkend="libpq-pqgetssl"><function>PQgetssl()</></>
        can still be used to call <productname>OpenSSL</>
        functions, <function>PQsslAttribute()</> returns <acronym>SSL</>
        information in an <acronym>SSL</>-implementation-independent way.
        (Future versions of libpq might support other <acronym>SSL</>
        implementations.)
       </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..
FIXME: Add docs about restartpoint behaviour change
-->
       <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 allows the allocation of a large number of <acronym>WAL</> files
        without keeping them if they are not needed. Thus the default
        for <xref linkend="guc-max-wal-size"> has been increased
        to <literal>1GB</>.
       </para>
      </listitem>

      <listitem>
<!--
2015-03-11 [57aa5b2] Fujii ..: Add GUC to enable compression of full page imag..
-->
       <para>
        Add configuration parameter <xref linkend="guc-wal-compression"> to
        control compression of full page images stored in <acronym>WAL</>
        (Rahila Syed, Michael Paquier)
       </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 running <link linkend="autovacuum">autovacuum workers</>
        to respond to configuration parameter changes (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 removed 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>
<!--
2014-06-18 [df8b7bc] Tom Lane: Improve our mechanism for controlling the Linux..
-->
       <para>
        Add environment variables <link
        linkend="linux-memory-overcommit"><envar>PG_OOM_ADJUST_FILE</></>
        and <link
        linkend="linux-memory-overcommit"><envar>PG_OOM_ADJUST_VALUE</></>
        to help control the Linux <acronym>OOM</> killer (Gurjeet Singh)
       </para>

       <para>
        The previous <acronym>OOM</> control infrastructure involved a
        compile-time option.
       </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 is pending a 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 setting from <filename>postgresql.auto.conf</>.
       </para>
      </listitem>

     </itemizedlist>

    </sect4>

   </sect3>

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

     <itemizedlist>

      <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>
<!--
2015-05-08 [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>
<!--
2015-04-29 [5aa2350] Andres..: Introduce replication progress tracking infrast..
2015-03-15 [4f1b890] Andres..: Merge the various forms of transaction commit &..
FIXME: Correct description
-->
       <para>
        Allow <link linkend="pg-replication-origin-create">labeling</> of
        the origin progress of logical replication changes (Andres Freund)
       </para>

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

      <listitem>
<!--
2015-04-21 [d811c03] Andres..: Add 'active_in' column to pg_replication_slots.
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</></> 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>INSERTS</></>
        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 functions <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 new <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>
      </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>
        Have <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>
        Have <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 row-level security control (Craig Ringer, KaiGai Kohei,
        Adam Brightwell, Dean Rasheed, Stephen Frost)
       </para>

       <para>
        This controls viewing and adding/modifying rows via 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 <literal>CURRENT</><literal>/SESSION_USER</> to specify the
        current user in some commands (Kyotaro Horiguchi, &Aacute;lvaro
        Herrera)
       </para>

       <para>
        Commands include <link linkend="SQL-ALTERUSER"><command>ALTER
        USER</></>,
       <link linkend="SQL-ALTERGROUP"><command>ALTER
        GROUP</></>, <link linkend="SQL-ALTERROLE"><command>ALTER
        ROLE</></>, <link linkend="SQL-GRANT"><command>GRANT</></>,
        and various <command>ALTER OBJECT / OWNER TO</> commands.
       </para>
      </listitem>

      <listitem>
<!--
2015-06-21 [ad89a5d] Alvaro..: Add transforms to pg_get_object_address and fr..
-->
       <para>
        Allow 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 (Stephen
        Frost)
       </para>

       <para>
        Previously only <command>UPDATE</>, <command>DELETE</>, and
        <command>TRUNCATE</> privileges allowed this.
       </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 name order
        (Tom Lane)
       </para>

       <para>
        The previous order 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 database settings to be
        changed more easily than modifying the <link
        linkend="catalog-pg-database"><structname>pg_database</></>
        system table.
       </para>
      </listitem>

     </itemizedlist>

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

      <itemizedlist>

      <listitem>
<!--
2014-07-10 [59efda3] Tom Lane: Implement IMPORT FOREIGN SCHEMA.
-->
       <para>
        Add support for <link
        linkend="SQL-IMPORTFOREIGNSCHEMA"><command>IMPORT FOREIGN
        SCHEMA</></> (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>
<!--
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>
        This also allows foreign tables to mark check constraints as not
        valid, and to set storage and <type>OID</> characteristics.
       </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>
        These 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>
<!--
2015-05-01 [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><xref linkend="SQL-CREATEEVENTTRIGGER"></title>

      <itemizedlist>

       <listitem>
<!--
2015-05-11 [b488c58] Alvaro..: Allow on-the-fly capture of DDL event details
FIXME: Better description?
-->
        <para>
         Add a set-returning function <link
         linkend="pg-event-trigger-ddl-command-end-functions"><function>pg_event_trigger_ddl_commands()</></>, which returns <acronym>DDL</> activity
         associated with event triggers (&Aacute;lvaro Herrera)
        </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 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
FIXME: Add more specifics?
-->
      <para>
       Tighten syntax of <link
       linkend="datatype-interval-input"><type>INTERVAL</></> precision
       specifications (Bruce Momjian)
      </para>

      <para>
       Only allow interval precision to be specified after the
       <literal>INTERVAL</> keyword if no units are specified.
      </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>

    </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 several generator functions for <type>JSONB</> that already
        existed for <type>JSON</> (Andrew Dunstan)
       </para>

       <para>
        These are <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()</></>.
       </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">operator</> <literal>||</>
        (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 <type>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 <link
        linkend="gist-builtin-opclasses-table"><type>point</>-to-<type>polygon</></>
        distance operator (&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 escape 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>
        Now, role membership is sufficient; previously only the same
        role could perform these operations.
       </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 files 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>

      <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</> <type>regnamespace</></> that returns
        the <type>OID</> of a role (Kyotaro Horiguchi)
       </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 aggregate accumulators
        (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 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 <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>
     </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 the <link
       linkend="app-pgreceivexlog"><application>pg_receivexlog</></>
       to synchronously flush <acronym>WAL</> to storage using
       <option>--synchronous</> (Furuya Osamu, Fujii Masao)
      </para>

      <para>
       Without this, <acronym>WAL</> files are fsynced 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 <option>--jobs</> (Dilip Kumar)
      </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 <literal>errors</> mode to <application>psql</>'s
         <varname>ECHO</> variable to display only failed commands
         (Pavel Stehule)
        </para>

        <para>
         This can also be enabled with the <application>psql</>
         <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 <application>psql</> <link
         linkend="APP-PSQL-variables"><envar>PROMPT</></> variables option
         (<literal>%l</>) to display the multiline statement line number
         (Sawada Masahiko)
        </para>
       </listitem>

       <listitem>
<!--
2015-03-28 [7655f4c] Andrew..: Add a pager_min_lines setting to psql
-->
        <para>
         Add <application>psql</> setting <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>
<!--
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</> outputs <application>psql</> variables
         and <literal>options</> shows command-line options.
         <command>\? commands</> is the default output. This help
         information can also be output via <literal>--help=section</>.
        </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.
        </para>
       </listitem>

       <listitem>
<!--
2014-11-22 [eca2b9b] Andrew..: Rework echo_hidden for \sf and \ef from commit ..
-->
        <para>
         Allow <application>psql</>'s <literal>\sf</> and <literal>\ef</>
         to 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 by another <application>pg_dump</> to
        use a share a consistent snapshot across <application>pg_dump</>
        processes.
       </para>
      </listitem>

      <listitem>
<!--
2014-07-07 [7700597] Tom Lane: In pg_dump, show server and pg_dump versions w..
-->
       <para>
        Always have <application>pg_dump</> print 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>
        Allow multiple <application>pg_ctl</> <option>-o</> options to
        be appended (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>

     </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>
        Allow multiple <application>pg_upgrade</>
        <option>-o</>/<option>-O</> options to be appended (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>
<!--
2015-03-18 [417f78a] Bruce ..: pg_upgrade: document use of rsync for slave up..
-->
       <para>
        Document the use of <application>rsync</> for standby server
        upgrades using <application>pg_upgrade</> (Stephen Frost,
        Bruce Momjian)
       </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 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
FIXME: Improve description, link
-->
       <para>
        Allow <application>pgbench</>'s <command>\set</> command to handle
        multi-operator expressions (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>
<!--
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</> or <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</></> 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>