Linux SRV-16 6.18.44-paas #1 SMP PREEMPT_DYNAMIC Thu Aug 13 10:08:12 UTC 2026 x86_64
/proc/self/root/proc/self/root/opt/postgresql-12/doc/html/
//proc/self/root/proc/self/root/opt/postgresql-12/doc/html/release-12.html
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>E.1. Release 12</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets V1.79.1" /><link rel="prev" href="release.html" title="Appendix E. Release Notes" /><link rel="next" href="release-prior.html" title="E.2. Prior Releases" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">E.1. Release 12</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="release.html" title="Appendix E. Release Notes">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="release.html" title="Appendix E. Release Notes">Up</a></td><th width="60%" align="center">Appendix E. Release Notes</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 12.0 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="release-prior.html" title="E.2. Prior Releases">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="RELEASE-12"><div class="titlepage"><div><div><h2 class="title" style="clear: both">E.1. Release 12</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="release-12.html#id-1.11.6.5.3">E.1.1. Overview</a></span></dt><dt><span class="sect2"><a href="release-12.html#id-1.11.6.5.4">E.1.2. Migration to Version 12</a></span></dt><dt><span class="sect2"><a href="release-12.html#id-1.11.6.5.5">E.1.3. Changes</a></span></dt><dt><span class="sect2"><a href="release-12.html#RELEASE-12-ACKNOWLEDGEMENTS">E.1.4. Acknowledgments</a></span></dt></dl></div><p><strong>Release date: </strong>2019-10-03</p><div class="sect2" id="id-1.11.6.5.3"><div class="titlepage"><div><div><h3 class="title">E.1.1. Overview</h3></div></div></div><p>
    Major enhancements in <span class="productname">PostgreSQL</span> 12 include:
   </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
      General performance improvements, including:
      </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "><li class="listitem"><p>
         Optimizations to space utilization and read/write performance for
         B-tree indexes
        </p></li><li class="listitem"><p>
         Partitioning performance enhancements, including improved query
         performance on tables with thousands of partitions, improved
         insertion performance with <a class="xref" href="sql-insert.html" title="INSERT"><span class="refentrytitle">INSERT</span></a> and <a class="xref" href="sql-copy.html" title="COPY"><span class="refentrytitle">COPY</span></a>, and the ability to execute <a class="link" href="sql-altertable.html#SQL-ALTERTABLE-ATTACH-PARTITION"><code class="command">ALTER TABLE ATTACH
         PARTITION</code></a> without blocking queries
        </p></li><li class="listitem"><p>
         Automatic (but overridable) inlining
         of <a class="link" href="queries-with.html" title="7.8. WITH Queries (Common Table Expressions)">common table expressions</a>
         (<acronym class="acronym">CTEs</acronym>)
        </p></li><li class="listitem"><p>
         Reduction of <acronym class="acronym">WAL</acronym> overhead for creation of
         <a class="link" href="gist.html" title="Chapter 64. GiST Indexes">GiST</a>, <a class="link" href="gin.html" title="Chapter 66. GIN Indexes">GIN</a>, and
         <a class="link" href="spgist.html" title="Chapter 65. SP-GiST Indexes">SP-GiST</a> indexes
        </p></li><li class="listitem"><p>
         Support for covering <a class="link" href="gist.html" title="Chapter 64. GiST Indexes">GiST</a> indexes, via
         the <a class="link" href="indexes-index-only-scans.html" title="11.9. Index-Only Scans and Covering Indexes"><code class="literal">INCLUDE</code></a>
         clause
        </p></li><li class="listitem"><p>
         Multi-column most-common-value (MCV) statistics can be defined
         via <a class="xref" href="sql-createstatistics.html" title="CREATE STATISTICS"><span class="refentrytitle">CREATE STATISTICS</span></a>, to support better
         plans for queries that test several non-uniformly-distributed
         columns
        </p></li></ul></div><p>
     </p></li><li class="listitem"><p>
      Enhancements to administrative functionality, including:
      </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "><li class="listitem"><p>
         <a class="link" href="sql-reindex.html#SQL-REINDEX-CONCURRENTLY" title="Rebuilding Indexes Concurrently"><code class="command">REINDEX
         CONCURRENTLY</code></a> can rebuild an index without
         blocking writes to its table
        </p></li><li class="listitem"><p>
         <a class="xref" href="app-pgchecksums.html" title="pg_checksums"><span class="refentrytitle"><span class="application">pg_checksums</span></span></a> can enable/disable page checksums
         (used for detecting data corruption) in an offline cluster
        </p></li><li class="listitem"><p>
         Progress reporting statistics for <a class="xref" href="sql-createindex.html" title="CREATE INDEX"><span class="refentrytitle">CREATE INDEX</span></a>,
         <a class="xref" href="sql-reindex.html" title="REINDEX"><span class="refentrytitle">REINDEX</span></a>, <a class="xref" href="sql-cluster.html" title="CLUSTER"><span class="refentrytitle">CLUSTER</span></a>,
         <a class="link" href="sql-vacuum.html" title="VACUUM">VACUUM FULL</a>, and
         <a class="xref" href="app-pgchecksums.html" title="pg_checksums"><span class="refentrytitle"><span class="application">pg_checksums</span></span></a>
        </p></li></ul></div><p>
     </p></li><li class="listitem"><p>
       Support for the <a class="link" href="functions-json.html#FUNCTIONS-SQLJSON-PATH" title="9.15.2. The SQL/JSON Path Language"><acronym class="acronym">SQL/JSON</acronym>
       path</a> language
     </p></li><li class="listitem"><p>
       Stored <a class="link" href="ddl-generated-columns.html" title="5.3. Generated Columns">generated columns</a>
     </p></li><li class="listitem"><p>
       <a class="link" href="collation.html#COLLATION-NONDETERMINISTIC" title="23.2.2.4. Nondeterministic Collations">Nondeterministic</a> ICU
       collations, enabling case-insensitive and accent-insensitive grouping
       and ordering
     </p></li><li class="listitem"><p>
      New authentication features, including:
      </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; "><li class="listitem"><p>
         Encryption of TCP/IP connections when using
         <a class="link" href="gssapi-auth.html" title="20.6. GSSAPI Authentication"><acronym class="acronym">GSSAPI</acronym></a>
         authentication
        </p></li><li class="listitem"><p>
         Discovery of LDAP servers using <acronym class="acronym">DNS SRV</acronym> records
        </p></li><li class="listitem"><p>
         Multi-factor authentication, using the <a class="link" href="auth-cert.html" title="20.12. Certificate Authentication">
         <code class="literal">clientcert=verify-full</code></a> option combined
         with an additional authentication method in
         <code class="filename">pg_hba.conf</code>
        </p></li></ul></div><p>
     </p></li></ul></div><p>
    The above items are explained in more detail in the sections below.
   </p></div><div class="sect2" id="id-1.11.6.5.4"><div class="titlepage"><div><div><h3 class="title">E.1.2. Migration to Version 12</h3></div></div></div><p>
    A dump/restore using <a class="xref" href="app-pg-dumpall.html" title="pg_dumpall"><span class="refentrytitle"><span class="application">pg_dumpall</span></span></a>, or use of <a class="xref" href="pgupgrade.html" title="pg_upgrade"><span class="refentrytitle"><span class="application">pg_upgrade</span></span></a>, is required for those wishing to migrate data
    from any previous release.
   </p><p>
    Version 12 contains a number of changes that may affect compatibility
    with previous releases.  Observe the following incompatibilities:
   </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
      Remove the special behavior of <a class="link" href="datatype-oid.html" title="8.19. Object Identifier Types">oid</a> columns (Andres Freund,
      John Naylor)
     </p><p>
      Previously, a normally-invisible <code class="structfield">oid</code>
      column could be specified during table creation using <code class="literal">WITH
      OIDS</code>; that ability has been removed.  Columns can still be
      explicitly declared as type <code class="type">oid</code>.  Operations on tables
      that have columns created using <code class="literal">WITH OIDS</code> will
      need adjustment.
     </p><p>
      The system catalogs that previously had
      hidden <code class="structfield">oid</code> columns now have
      ordinary <code class="structfield">oid</code> columns.
      Hence, <code class="command">SELECT *</code> will now output those columns,
      whereas previously they would be displayed only if selected
      explicitly.
     </p></li><li class="listitem"><p>
      Remove data types <code class="type">abstime</code>, <code class="type">reltime</code>,
      and <code class="type">tinterval</code> (Andres Freund)
     </p><p>
      These are obsoleted by SQL-standard types such
      as <code class="type">timestamp</code>.
     </p></li><li class="listitem"><p>
      Remove the <code class="filename">timetravel</code> extension
      (Andres Freund)
     </p></li><li class="listitem"><p>
      Move <code class="filename">recovery.conf</code> settings into <a class="link" href="runtime-config-wal.html#RUNTIME-CONFIG-WAL-ARCHIVE-RECOVERY" title="19.5.4. Archive Recovery"><code class="filename">postgresql.conf</code></a>
      (Masao Fujii, Simon Riggs, Abhijit Menon-Sen, Sergei Kornilov)
     </p><p>
      <code class="filename">recovery.conf</code> is no longer used,
      and the server will not start if that file exists.  <a class="link" href="runtime-config-wal.html#RUNTIME-CONFIG-WAL-ARCHIVE-RECOVERY" title="19.5.4. Archive Recovery">recovery.signal</a>
      and <code class="filename">standby.signal</code> files are now used to switch
      into non-primary mode.  The <code class="varname">trigger_file</code> setting
      has been renamed to <a class="xref" href="runtime-config-replication.html#GUC-PROMOTE-TRIGGER-FILE">promote_trigger_file</a>.  The
      <code class="varname">standby_mode</code> setting has been removed.
     </p></li><li class="listitem"><p>
      Do not allow multiple conflicting <a class="link" href="runtime-config-wal.html#RUNTIME-CONFIG-WAL-RECOVERY-TARGET" title="19.5.5. Recovery Target"><code class="varname">recovery_target</code>*</a>
      specifications (Peter Eisentraut)
     </p><p>
      Specifically, only allow one of <a class="xref" href="runtime-config-wal.html#GUC-RECOVERY-TARGET">recovery_target</a>, <a class="xref" href="runtime-config-wal.html#GUC-RECOVERY-TARGET-LSN">recovery_target_lsn</a>,
      <a class="xref" href="runtime-config-wal.html#GUC-RECOVERY-TARGET-NAME">recovery_target_name</a>,
      <a class="xref" href="runtime-config-wal.html#GUC-RECOVERY-TARGET-TIME">recovery_target_time</a>, and <a class="xref" href="runtime-config-wal.html#GUC-RECOVERY-TARGET-XID">recovery_target_xid</a>.  Previously, multiple different
      instances of these parameters could be specified, and the last one
      was honored.  Now, only one can be specified, though the same one can
      be specified multiple times and the last specification is honored.
     </p></li><li class="listitem"><p>
      Cause recovery to advance to the latest timeline by default
      (Peter Eisentraut)
     </p><p>
      Specifically, <a class="xref" href="runtime-config-wal.html#GUC-RECOVERY-TARGET-TIMELINE">recovery_target_timeline</a> now
      defaults to <code class="literal">latest</code>.  Previously, it defaulted
      to <code class="literal">current</code>.
     </p></li><li class="listitem"><p>
      Refactor code for <a class="link" href="functions-geometry.html" title="9.11. Geometric Functions and Operators">geometric
      functions and operators</a> (Emre Hasegeli)
     </p><p>
      This could lead to more accurate, but slightly different, results
      compared to previous releases.  Notably, cases involving NaN,
      underflow, overflow, and division by zero are handled more
      consistently than before.
     </p></li><li class="listitem"><p>
      Improve performance by using a new algorithm for output
      of <a class="link" href="datatype-numeric.html#DATATYPE-FLOAT" title="8.1.3. Floating-Point Types"><code class="type">real</code></a>
      and <code class="type">double precision</code> values (Andrew Gierth)
     </p><p>
      Previously, displayed floating-point values were rounded to 6
      (for <code class="type">real</code>) or 15 (for <code class="type">double precision</code>)
      digits by default, adjusted by the value of
      <a class="xref" href="runtime-config-client.html#GUC-EXTRA-FLOAT-DIGITS">extra_float_digits</a>.  Now,
      whenever <code class="varname">extra_float_digits</code> is more than zero (as
      it now is by default), only the minimum number of digits required to
      preserve the exact binary value are output.  The behavior is the
      same as before when <code class="varname">extra_float_digits</code> is set to
      zero or less.
     </p><p>
      Also, formatting of floating-point exponents is now uniform across
      platforms: two digits are used unless three are necessary.  In
      previous releases, Windows builds always printed three digits.
     </p></li><li class="listitem"><p>
       <a class="link" href="functions-math.html#FUNCTIONS-MATH-RANDOM-TABLE" title="Table 9.6. Random Functions"><code class="function">random()</code></a>
      and <code class="function">setseed()</code> now behave uniformly across
      platforms (Tom Lane)
     </p><p>
      The sequence of <code class="function">random()</code> values generated
      following a <code class="function">setseed()</code> call with a particular
      seed value is likely to be different now than before.  However, it
      will also be repeatable, which was not previously guaranteed because
      of interference from other uses of random numbers inside the server.
      The SQL <code class="function">random()</code> function now has its own
      private per-session state to forestall that.
     </p></li><li class="listitem"><p>
      Change SQL-style
      <a class="link" href="functions-matching.html#FUNCTIONS-SIMILARTO-REGEXP" title="9.7.2. SIMILAR TO Regular Expressions"><code class="function">substring()</code></a>
      to have standard-compliant greediness behavior (Tom Lane)
     </p><p>
      In cases where the pattern can be matched in more than one way, the
      initial sub-pattern is now treated as matching the least possible
      amount of text rather than the greatest; for example, a pattern such
      as <code class="literal">%#"aa*#"%</code> now selects the first group
      of <code class="literal">a</code>'s from the input, not the last group.
     </p></li><li class="listitem"><p>
      Do not pretty-print the result
      of <a class="link" href="functions-xml.html" title="9.14. XML Functions"><code class="function">xpath()</code></a>
      or the <code class="literal">XMLTABLE</code> construct (Tom Lane)
     </p><p>
      In some cases, these functions would insert extra whitespace
      (newlines and/or spaces) in nodeset values.  This is undesirable
      since depending on usage, the whitespace might be considered
      semantically significant.
     </p></li><li class="listitem"><p>
      Rename command-line tool
      <span class="application">pg_verify_checksums</span> to <a class="xref" href="app-pgchecksums.html" title="pg_checksums"><span class="refentrytitle"><span class="application">pg_checksums</span></span></a> (Michaël Paquier)
     </p></li><li class="listitem"><p>
      In <a class="xref" href="app-pgrestore.html" title="pg_restore"><span class="refentrytitle">pg_restore</span></a>, require specification of
      <code class="literal">-f -</code> to send the dump contents to standard output
      (Euler Taveira)
     </p><p>
      Previously, this happened by default if no destination was
      specified, but that was deemed to be unfriendly.
     </p></li><li class="listitem"><p>
      Disallow non-unique abbreviations
      in <span class="application">psql</span>'s <code class="command">\pset format</code>
      command (Daniel Vérité)
     </p><p>
      Previously, for example, <code class="command">\pset format a</code> chose
      <code class="literal">aligned</code>; it will now fail since that could
      equally well mean <code class="literal">asciidoc</code>.
     </p></li><li class="listitem"><p>
      In new btree indexes, the maximum index entry length is
      reduced by eight bytes, to improve handling of duplicate entries
      (Peter Geoghegan)
     </p><p>
      This means that a <a class="xref" href="sql-reindex.html" title="REINDEX"><span class="refentrytitle">REINDEX</span></a> operation on an
      index <span class="application">pg_upgrade</span>'d from a previous
      release could potentially fail.
     </p></li><li class="listitem"><p>
      Cause <a class="link" href="sql-dropfunction.html" title="DROP FUNCTION"><code class="command">DROP IF EXISTS
      FUNCTION</code></a>/<code class="literal">PROCEDURE</code>/<code class="literal">AGGREGATE</code>/<code class="literal">ROUTINE</code>
      to generate an error if no argument list is supplied and there are
      multiple matching objects (David Rowley)
     </p><p>
      Also improve the error message in such cases.
     </p></li><li class="listitem"><p>
      Split the <a class="link" href="catalog-pg-statistic-ext.html" title="51.51. pg_statistic_ext"><code class="structname">pg_statistic_ext</code></a>
      catalog into two catalogs, and add the <a class="link" href="view-pg-stats-ext.html" title="51.89. pg_stats_ext"><code class="structname">pg_stats_ext</code></a>
      view of it (Dean Rasheed, Tomas Vondra)
     </p><p>
      This change supports hiding potentially-sensitive statistics data
      from unprivileged users.
     </p></li><li class="listitem"><p>
      Remove obsolete <a class="link" href="catalog-pg-constraint.html" title="51.13. pg_constraint"><code class="structname">pg_constraint</code></a>.<code class="structfield">consrc</code>
      column (Peter Eisentraut)
     </p></li><li class="listitem"><p>
      Remove obsolete <a class="link" href="catalog-pg-attrdef.html" title="51.6. pg_attrdef"><code class="structname">pg_attrdef</code></a>.<code class="structfield">adsrc</code>
      column (Peter Eisentraut)
     </p></li><li class="listitem"><p>
      Mark table columns of type <a class="link" href="datatype-character.html#DATATYPE-CHARACTER-SPECIAL-TABLE" title="Table 8.5. Special Character Types">name</a> as having
      <span class="quote">“<span class="quote">C</span>”</span> collation by default (Tom Lane, Daniel Vérité)
     </p><p>
      The comparison operators for data type <code class="type">name</code> can now use
      any collation, rather than always using <span class="quote">“<span class="quote">C</span>”</span> collation.
      To preserve the previous semantics of queries, columns of
      type <code class="type">name</code> are now explicitly marked as
      having <span class="quote">“<span class="quote">C</span>”</span> collation.  A side effect of this is that
      regular-expression operators on <code class="type">name</code> columns will now
      use the <span class="quote">“<span class="quote">C</span>”</span> collation by default, not the database
      collation, to determine the behavior of locale-dependent regular
      expression patterns (such as <code class="literal">\w</code>).  If you want
      non-C behavior for a regular expression on a <code class="type">name</code>
      column, attach an explicit <code class="literal">COLLATE</code> clause.  (For
      user-defined <code class="type">name</code> columns, another possibility is to
      specify a different collation at table creation time; but that just
      moves the non-backwards-compatibility to the comparison operators.)
     </p></li><li class="listitem"><p>
      Treat object-name columns in
      the <a class="link" href="information-schema.html" title="Chapter 36. The Information Schema"><code class="structname">information_schema</code></a>
      views as being of type <code class="type">name</code>, not <code class="type">varchar</code>
      (Tom Lane)
     </p><p>
      Per the SQL standard, object-name columns in
      the <code class="structname">information_schema</code> views are declared
      as being of domain type <code class="type">sql_identifier</code>.
      In <span class="productname">PostgreSQL</span>, the underlying catalog
      columns are really of type <code class="type">name</code>.  This change
      makes <code class="type">sql_identifier</code> be a domain
      over <code class="type">name</code>, rather than <code class="type">varchar</code> as before.
      This eliminates a semantic mismatch in comparison and sorting
      behavior, which can greatly improve the performance of queries
      on <code class="structname">information_schema</code> views that restrict
      an object-name column.  Note however that inequality restrictions,
      for example
</p><pre class="programlisting">
SELECT ... FROM information_schema.tables WHERE table_name &lt; 'foo';
</pre><p>
      will now use <span class="quote">“<span class="quote">C</span>”</span>-locale comparison semantics by
      default, rather than the database's default collation as before.
      Sorting on these columns will also follow <span class="quote">“<span class="quote">C</span>”</span> ordering
      rules.  The previous behavior (and inefficiency) can be enforced by
      adding a <code class="literal">COLLATE "default"</code> clause.
     </p></li><li class="listitem"><p>
      Remove the ability to disable dynamic shared memory (Kyotaro
      Horiguchi)
     </p><p>
      Specifically, <a class="xref" href="runtime-config-resource.html#GUC-DYNAMIC-SHARED-MEMORY-TYPE">dynamic_shared_memory_type</a>
      can no longer be set to <code class="literal">none</code>.
     </p></li></ul></div></div><div class="sect2" id="id-1.11.6.5.5"><div class="titlepage"><div><div><h3 class="title">E.1.3. Changes</h3></div></div></div><p>
     Below you will find a detailed account of the changes between
     <span class="productname">PostgreSQL</span> 12 and the previous
     major release.
    </p><div class="sect3" id="id-1.11.6.5.5.3"><div class="titlepage"><div><div><h4 class="title">E.1.3.1. Server</h4></div></div></div><div class="sect4" id="id-1.11.6.5.5.3.2"><div class="titlepage"><div><div><h5 class="title">E.1.3.1.1. <a class="link" href="ddl-partitioning.html" title="5.11. Table Partitioning">Partitioning</a></h5></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
        Improve performance of many operations on partitioned tables
        (Amit Langote, David Rowley, Tom Lane, Álvaro Herrera)
       </p><p>
        Allow tables with thousands of child partitions to be processed
        efficiently by operations that only affect a small number of
        partitions.
       </p></li><li class="listitem"><p>
        Allow <a class="link" href="ddl-constraints.html#DDL-CONSTRAINTS-FK" title="5.4.5. Foreign Keys">foreign keys</a>
        to reference partitioned tables (Álvaro Herrera)
       </p></li><li class="listitem"><p>
        Improve speed of <code class="command">COPY</code> into partitioned tables
        (David Rowley)
       </p></li><li class="listitem"><p>
        Allow partition bounds to be any expression (Kyotaro Horiguchi,
        Tom Lane, Amit Langote)
       </p><p>
        Such expressions are evaluated at partitioned-table creation time.
        Previously, only simple constants were allowed as partition bounds.
       </p></li><li class="listitem"><p>
        Allow <code class="command">CREATE TABLE</code>'s tablespace specification
        for a partitioned table to affect the tablespace of its children
        (David Rowley, Álvaro Herrera)
       </p></li><li class="listitem"><p>
        Avoid sorting when partitions are already being scanned in the
        necessary order (David Rowley)
       </p></li><li class="listitem"><p>
        <a class="link" href="sql-altertable.html" title="ALTER TABLE"><code class="command">ALTER TABLE ATTACH
        PARTITION</code></a> is now performed with reduced locking
        requirements (Robert Haas)
       </p></li><li class="listitem"><p>
        Add partition introspection functions (Michaël Paquier, Álvaro
        Herrera, Amit Langote)
       </p><p>
        The new function <a class="link" href="functions-admin.html#FUNCTIONS-INFO-PARTITION" title="Table 9.92. Partitioning Information Functions"><code class="function">pg_partition_root()</code></a>
        returns the top-most parent of a partition tree, <a class="link" href="functions-admin.html#FUNCTIONS-INFO-PARTITION" title="Table 9.92. Partitioning Information Functions"><code class="function">pg_partition_ancestors()</code></a>
        reports all ancestors of a partition, and <a class="link" href="functions-admin.html#FUNCTIONS-INFO-PARTITION" title="Table 9.92. Partitioning Information Functions"><code class="function">pg_partition_tree()</code></a>
        displays information about partitions.
       </p></li><li class="listitem"><p>
        Include partitioned indexes in the system view <a class="link" href="view-pg-indexes.html" title="51.73. pg_indexes"><code class="structname">pg_indexes</code></a>
        (Suraj Kharage)
       </p></li><li class="listitem"><p>
        Add <span class="application">psql</span> command <code class="command">\dP</code>
        to list partitioned tables and indexes (Pavel Stehule)
       </p></li><li class="listitem"><p>
        Improve <span class="application">psql</span> <code class="command">\d</code>
        and <code class="command">\z</code> display of partitioned tables (Pavel
        Stehule, Michaël Paquier, Álvaro Herrera)
       </p></li><li class="listitem"><p>
        Fix bugs that could cause <code class="command">ALTER TABLE DETACH
        PARTITION</code> to leave behind incorrect dependency state,
        allowing subsequent operations to misbehave, for example by not
        dropping a former partition child index when its table is dropped
        (Tom Lane)
       </p></li></ul></div></div><div class="sect4" id="id-1.11.6.5.5.3.3"><div class="titlepage"><div><div><h5 class="title">E.1.3.1.2. Indexes</h5></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
        Improve performance and space utilization of btree indexes with
        many duplicates (Peter Geoghegan, Heikki Linnakangas)
       </p><p>
        Previously, duplicate index entries were stored unordered within
        their duplicate groups.  This caused overhead during index
        inserts, wasted space due to excessive page splits, and it reduced
        <code class="command">VACUUM</code>'s ability to recycle entire pages.
        Duplicate index entries are now sorted in heap-storage order.
       </p><p>
        Indexes <span class="application">pg_upgrade</span>'d from previous
        releases will not have these benefits.
       </p></li><li class="listitem"><p>
        Allow multi-column btree indexes to be smaller (Peter Geoghegan,
        Heikki Linnakangas)
       </p><p>
        Internal pages and min/max leaf page indicators now only store
        index keys until the change key, rather than all indexed keys.
        This also improves the locality of index access.
       </p><p>
        Indexes <span class="application">pg_upgrade</span>'d from previous
        releases will not have these benefits.
       </p></li><li class="listitem"><p>
        Improve speed of btree index insertions by reducing locking
        overhead (Alexander Korotkov)
       </p></li><li class="listitem"><p>
        Support <a class="link" href="indexes-index-only-scans.html" title="11.9. Index-Only Scans and Covering Indexes"><code class="literal">INCLUDE</code></a> columns
        in <a class="link" href="gist.html" title="Chapter 64. GiST Indexes">GiST</a> indexes (Andrey Borodin)
       </p></li><li class="listitem"><p>
        Add support for nearest-neighbor (<acronym class="acronym">KNN</acronym>) searches
        of <a class="link" href="spgist.html" title="Chapter 65. SP-GiST Indexes">SP-GiST</a> indexes (Nikita Glukhov,
        Alexander Korotkov, Vlad Sterzhanov)
       </p></li><li class="listitem"><p>
        Reduce the <acronym class="acronym">WAL</acronym> write overhead
        of <acronym class="acronym">GiST</acronym>, <acronym class="acronym">GIN</acronym>, and
        <acronym class="acronym">SP-GiST</acronym> index creation (Anastasia Lubennikova,
        Andrey V. Lepikhov)
       </p></li><li class="listitem"><p>
        Allow index-only scans to be more efficient on indexes with many
        columns (Konstantin Knizhnik)
       </p></li><li class="listitem"><p>
        Improve the performance of vacuum scans of GiST indexes (Andrey
        Borodin, Konstantin Kuznetsov, Heikki Linnakangas)
       </p></li><li class="listitem"><p>
        Delete empty leaf pages during <acronym class="acronym">GiST</acronym>
        <code class="command">VACUUM</code> (Andrey Borodin)
       </p></li><li class="listitem"><p>
        Reduce locking requirements for index renaming (Peter Eisentraut)
       </p></li></ul></div></div><div class="sect4" id="id-1.11.6.5.5.3.4"><div class="titlepage"><div><div><h5 class="title">E.1.3.1.3. Optimizer</h5></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
        Allow <a class="xref" href="sql-createstatistics.html" title="CREATE STATISTICS"><span class="refentrytitle">CREATE STATISTICS</span></a> to create
        most-common-value statistics for multiple columns (Tomas Vondra)
       </p><p>
        This improves optimization for queries that test several columns,
        requiring an estimate of the combined effect of
        several <code class="literal">WHERE</code> clauses.  If the columns are
        correlated and have non-uniform distributions then multi-column
        statistics will allow much better estimates.
       </p></li><li class="listitem"><p>
        Allow <a class="link" href="queries-with.html" title="7.8. WITH Queries (Common Table Expressions)">common table expressions</a>
        (<acronym class="acronym">CTEs</acronym>) to be inlined into the outer query
        (Andreas Karlsson, Andrew Gierth, David Fetter, Tom Lane)
       </p><p>
        Specifically, <acronym class="acronym">CTE</acronym>s are automatically inlined if
        they have no side-effects, are not recursive, and are referenced
        only once in the query.  Inlining can be prevented by
        specifying <code class="literal">MATERIALIZED</code>, or forced for
        multiply-referenced <acronym class="acronym">CTE</acronym>s by
        specifying <code class="literal">NOT MATERIALIZED</code>.  Previously,
        <acronym class="acronym">CTE</acronym>s were never inlined and were always
        evaluated before the rest of the query.
       </p></li><li class="listitem"><p>
        Allow control over when generic plans are used for prepared
        statements (Pavel Stehule)
       </p><p>
        This is controlled by the <a class="xref" href="runtime-config-query.html#GUC-PLAN-CACHE_MODE">plan_cache_mode</a>
        server parameter.
       </p></li><li class="listitem"><p>
        Improve optimization of partition and <code class="literal">UNION ALL</code>
        queries that have only a single child (David Rowley)
       </p></li><li class="listitem"><p>
        Improve processing of <a class="link" href="domains.html" title="8.18. Domain Types">domains</a> that
        have no check constraints (Tom Lane)
       </p><p>
        Domains that are being used purely as type aliases no longer cause
        optimization difficulties.
       </p></li><li class="listitem"><p>
        Pre-evaluate calls of <a class="link" href="functions-conditional.html#FUNCTIONS-GREATEST-LEAST" title="9.17.4. GREATEST and LEAST"><code class="literal">LEAST</code></a>
        and <code class="literal">GREATEST</code> when their arguments are constants
        (Vik Fearing)
       </p></li><li class="listitem"><p>
        Improve optimizer's ability to verify that partial indexes
        with <code class="literal">IS NOT NULL</code> conditions are usable in
        queries (Tom Lane, James Coleman)
       </p><p>
        Usability can now be recognized in more cases where the calling
        query involves casts or
        large <code class="literal"><em class="replaceable"><code>x</code></em> IN
        (<em class="replaceable"><code>array</code></em>)</code> clauses.
       </p></li><li class="listitem"><p>
        Compute <code class="command">ANALYZE</code> statistics using the collation
        defined for each column (Tom Lane)
       </p><p>
        Previously, the database's default collation was used for all
        statistics.  This potentially gives better optimizer behavior for
        columns with non-default collations.
       </p></li><li class="listitem"><p>
        Improve selectivity estimates for inequality comparisons
        on <a class="link" href="ddl-system-columns.html" title="5.5. System Columns"><code class="structfield">ctid</code></a>
        columns (Edmund Horner)
       </p></li><li class="listitem"><p>
        Improve optimization of joins on columns of type <a class="link" href="datatype-oid.html" title="8.19. Object Identifier Types"><code class="type">tid</code></a>
        (Tom Lane)
       </p><p>
        These changes primarily improve the efficiency of self-joins
        on <code class="structfield">ctid</code> columns.
       </p></li><li class="listitem"><p>
        Fix the leakproofness designations of some btree comparison operators
        and support functions (Tom Lane)
       </p><p>
        This allows some optimizations that previously would not have been
        applied in the presence of security barrier views or row-level
        security.
       </p></li></ul></div></div><div class="sect4" id="id-1.11.6.5.5.3.5"><div class="titlepage"><div><div><h5 class="title">E.1.3.1.4. General Performance</h5></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
        Enable <a class="link" href="jit.html" title="Chapter 31. Just-in-Time Compilation (JIT)">Just-in-Time</a>
        (<acronym class="acronym">JIT</acronym>) compilation by default, if the server
        has been built with support for it (Andres Freund)
       </p><p>
        Note that this support is not built by default, but has to be
        selected explicitly while configuring the build.
       </p></li><li class="listitem"><p>
        Speed up keyword lookup (John Naylor, Joerg Sonnenberger, Tom Lane)
       </p></li><li class="listitem"><p>
        Improve search performance for multi-byte characters
        in <code class="function">position()</code> and related functions (Heikki
        Linnakangas)
       </p></li><li class="listitem"><p>
        Allow <a class="link" href="storage-toast.html" title="68.2. TOAST">toasted</a>
        values to be minimally decompressed (Paul Ramsey)
       </p><p>
        This is useful for routines that only need to examine the initial
        portion of a toasted field.
       </p></li><li class="listitem"><p>
        Allow <a class="link" href="sql-altertable.html" title="ALTER TABLE"><code class="command">ALTER TABLE ... SET
        NOT NULL</code></a> to avoid unnecessary table scans (Sergei
        Kornilov)
       </p><p>
        This can be optimized when the table's column constraints can be
        recognized as disallowing nulls.
       </p></li><li class="listitem"><p>
        Allow <code class="command">ALTER TABLE ... SET DATA TYPE</code> changing between
        <code class="type">timestamp</code> and <code class="type">timestamptz</code> to avoid a
        table rewrite when the session time zone is <acronym class="acronym">UTC</acronym>
        (Noah Misch)
       </p><p>
        In the <acronym class="acronym">UTC</acronym> time zone, these two data types are
        binary compatible.
       </p></li><li class="listitem"><p>
        Improve speed in converting strings to
        <code class="type">int2</code> or <code class="type">int4</code> integers (Andres Freund)
       </p></li><li class="listitem"><p>
        Allow parallelized queries when in <a class="link" href="transaction-iso.html#XACT-SERIALIZABLE" title="13.2.3. Serializable Isolation Level"><code class="literal">SERIALIZABLE</code></a>
        isolation mode (Thomas Munro)
       </p><p>
        Previously, parallelism was disabled when in this mode.
       </p></li><li class="listitem"><p>
        Use <code class="function">pread()</code> and <code class="function">pwrite()</code>
        for random I/O (Oskari Saarenmaa, Thomas Munro)
       </p><p>
        This reduces the number of system calls required for I/O.
       </p></li><li class="listitem"><p>
        Improve the speed of setting the <a class="link" href="runtime-config-logging.html#GUC-UPDATE-PROCESS-TITLE">process title</a> on
        <span class="systemitem">FreeBSD</span> (Thomas Munro)
       </p></li></ul></div></div><div class="sect4" id="id-1.11.6.5.5.3.6"><div class="titlepage"><div><div><h5 class="title">E.1.3.1.5. Monitoring</h5></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
        Allow logging of statements from only a percentage of transactions
        (Adrien Nayrat)
       </p><p>
        The parameter <a class="xref" href="runtime-config-logging.html#GUC-LOG-TRANSACTION-SAMPLE-RATE">log_transaction_sample_rate</a>
        controls this.
       </p></li><li class="listitem"><p>
        Add progress reporting to <code class="command">CREATE INDEX</code> and
        <code class="command">REINDEX</code> operations (Álvaro Herrera, Peter
        Eisentraut)
       </p><p>
        Progress is reported in the <a class="link" href="progress-reporting.html#CREATE-INDEX-PROGRESS-REPORTING" title="27.4.1. CREATE INDEX Progress Reporting"><code class="structname">pg_stat_progress_create_index</code></a>
        system view.
       </p></li><li class="listitem"><p>
        Add progress reporting to <code class="command">CLUSTER</code> and
        <code class="command">VACUUM FULL</code> (Tatsuro Yamada)
       </p><p>
        Progress is reported in the <a class="link" href="progress-reporting.html#CLUSTER-PROGRESS-REPORTING" title="27.4.3. CLUSTER Progress Reporting"><code class="structname">pg_stat_progress_cluster</code></a>
        system view.
       </p></li><li class="listitem"><p>
        Add progress reporting to <a class="xref" href="app-pgchecksums.html" title="pg_checksums"><span class="refentrytitle"><span class="application">pg_checksums</span></span></a>
        (Michael Banck, Bernd Helmle)
       </p><p>
        This is enabled with the option <code class="option">--progress</code>.
       </p></li><li class="listitem"><p>
        Add counter of checksum failures to
        <code class="structname">pg_stat_database</code> (Magnus Hagander)
       </p></li><li class="listitem"><p>
        Add tracking of global objects in system view
        <code class="structname">pg_stat_database</code> (Julien Rouhaud)
       </p><p>
        Global objects are shown with a <a class="link" href="monitoring-stats.html#PG-STAT-DATABASE-VIEW" title="Table 27.12. pg_stat_database View"><code class="structname">pg_stat_database</code></a>.<code class="structfield">datid</code>
        value of zero.
       </p></li><li class="listitem"><p>
        Add the ability to list the contents of the archive directory
        (Christoph Moench-Tegeder)
       </p><p>
        The function is <a class="link" href="functions-admin.html#FUNCTIONS-ADMIN-GENFILE-TABLE" title="Table 9.94. Generic File Access Functions"><code class="function">pg_ls_archive_statusdir()</code></a>.
       </p></li><li class="listitem"><p>
        Add the ability to list the contents of temporary directories
        (Nathan Bossart)
       </p><p>
        The function, <a class="link" href="functions-admin.html#FUNCTIONS-ADMIN-GENFILE-TABLE" title="Table 9.94. Generic File Access Functions"><code class="function">pg_ls_tmpdir()</code></a>,
        optionally allows specification of a tablespace.
       </p></li><li class="listitem"><p>
        Add information about the client certificate to the system view <a class="link" href="monitoring-stats.html#PG-STAT-SSL-VIEW" title="Table 27.8. pg_stat_ssl View"><code class="structname">pg_stat_ssl</code></a>
        (Peter Eisentraut)
       </p><p>
        The new columns are <code class="structfield">client_serial</code>
        and <code class="structfield">issuer_dn</code>.  Column
        <code class="structfield">clientdn</code> has been renamed to
        <code class="structfield">client_dn</code> for clarity.
       </p></li><li class="listitem"><p>
        Restrict visibility of rows in <code class="structname">pg_stat_ssl</code>
        for unprivileged users (Peter Eisentraut)
       </p></li><li class="listitem"><p>
        At server start, emit a log message including the server
        version number (Christoph Berg)
       </p></li><li class="listitem"><p>
        Prevent logging <span class="quote">“<span class="quote">incomplete startup packet</span>”</span> if a new
        connection is immediately closed (Tom Lane)
       </p><p>
        This avoids log spam from certain forms of monitoring.
       </p></li><li class="listitem"><p>
        Include the <a class="xref" href="runtime-config-logging.html#GUC-APPLICATION-NAME">application_name</a>, if set,
        in <a class="xref" href="runtime-config-logging.html#GUC-LOG-CONNECTIONS">log_connections</a> log messages (Don Seiler)
       </p></li><li class="listitem"><p>
        Make the walreceiver set its application name to the cluster name,
        if set (Peter Eisentraut)
       </p></li><li class="listitem"><p>
        Add the timestamp of the last received standby message to <a class="link" href="monitoring-stats.html#PG-STAT-REPLICATION-VIEW" title="Table 27.5. pg_stat_replication View"><code class="structname">pg_stat_replication</code></a>
        (Lim Myungkyu)
       </p></li><li class="listitem"><p>
        Add a <a class="link" href="monitoring-stats.html#WAIT-EVENT-TABLE" title="Table 27.4. wait_event Description">wait event</a> for fsync
        of <acronym class="acronym">WAL</acronym> segments (Konstantin Knizhnik)
       </p></li></ul></div></div><div class="sect4" id="id-1.11.6.5.5.3.7"><div class="titlepage"><div><div><h5 class="title">E.1.3.1.6. <acronym class="acronym">Authentication</acronym></h5></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
        Add <a class="link" href="gssapi-auth.html" title="20.6. GSSAPI Authentication"><acronym class="acronym">GSSAPI</acronym></a>
        encryption support (Robbie Harwood, Stephen Frost)
       </p><p>
        This feature allows TCP/IP connections to be encrypted when using
        GSSAPI authentication, without having to set up a separate
        encryption facility such as SSL.
        In support of this, add <code class="literal">hostgssenc</code>
        and <code class="literal">hostnogssenc</code> record types in <a class="link" href="auth-pg-hba-conf.html" title="20.1. The pg_hba.conf File"><code class="filename">pg_hba.conf</code></a>
        for selecting connections that do or do not use GSSAPI encryption,
        corresponding to the existing <code class="literal">hostssl</code>
        and <code class="literal">hostnossl</code> record types.
        There is also a new <a class="xref" href="libpq-connect.html#LIBPQ-CONNECT-GSSENCMODE">gssencmode</a>
        libpq option, and a <a class="xref" href="monitoring-stats.html#PG-STAT-GSSAPI-VIEW" title="Table 27.9. pg_stat_gssapi View">pg_stat_gssapi</a> system
        view.
       </p></li><li class="listitem"><p>
        Allow the <a class="link" href="auth-cert.html" title="20.12. Certificate Authentication"><code class="literal">clientcert</code></a>
        <code class="filename">pg_hba.conf</code> option to check that the database
        user name matches the client certificate's common name
        (Julian Markwort, Marius Timmer)
       </p><p>
        This new check is enabled with
        <code class="literal">clientcert=verify-full</code>.
       </p></li><li class="listitem"><p>
        Allow discovery of an <a class="link" href="auth-ldap.html" title="20.10. LDAP Authentication"><acronym class="acronym">LDAP</acronym></a> server using
        <acronym class="acronym">DNS SRV</acronym> records (Thomas Munro)
       </p><p>
        This avoids the requirement of specifying
        <code class="literal">ldapserver</code>.  It is only supported if
        <span class="productname">PostgreSQL</span> is compiled with
        <span class="productname">OpenLDAP</span>.
       </p></li></ul></div></div><div class="sect4" id="id-1.11.6.5.5.3.8"><div class="titlepage"><div><div><h5 class="title">E.1.3.1.7. Server Configuration</h5></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
        Add ability to enable/disable cluster checksums using <a class="xref" href="app-pgchecksums.html" title="pg_checksums"><span class="refentrytitle"><span class="application">pg_checksums</span></span></a> (Michael Banck, Michaël Paquier)
       </p><p>
        The cluster must be shut down for these operations.
       </p></li><li class="listitem"><p>
        Reduce the default value of <a class="xref" href="runtime-config-autovacuum.html#GUC-AUTOVACUUM-VACUUM-COST-DELAY">autovacuum_vacuum_cost_delay</a> to 2ms (Tom Lane)
       </p><p>
        This allows autovacuum operations to proceed faster by default.
       </p></li><li class="listitem"><p>
        Allow <a class="xref" href="runtime-config-resource.html#GUC-VACUUM-COST-DELAY">vacuum_cost_delay</a> to specify
        sub-millisecond delays, by accepting fractional values (Tom Lane)
       </p></li><li class="listitem"><p>
        Allow time-based server parameters to use units of <a class="link" href="config-setting.html" title="19.1. Setting Parameters">microseconds</a>
        (<code class="literal">us</code>) (Tom Lane)
       </p></li><li class="listitem"><p>
        Allow fractional input for integer server parameters (Tom Lane)
       </p><p>
        For example, <code class="command">SET work_mem = '30.1GB'</code> is now
        allowed, even though <code class="varname">work_mem</code> is an integer
        parameter.  The value will be rounded to an integer after any
        required units conversion.
       </p></li><li class="listitem"><p>
        Allow units to be defined for floating-point server parameters
        (Tom Lane)
       </p></li><li class="listitem"><p>
        Add <a class="xref" href="runtime-config-replication.html#GUC-WAL-RECYCLE">wal_recycle</a> and <a class="xref" href="runtime-config-replication.html#GUC-WAL-INIT-ZERO">wal_init_zero</a> server parameters to control
        <acronym class="acronym">WAL</acronym> file recycling (Jerry Jelinek)
       </p><p>
        Avoiding file recycling can be beneficial on copy-on-write file
        systems like <span class="productname">ZFS</span>.
       </p></li><li class="listitem"><p>
        Add server parameter <a class="xref" href="runtime-config-connection.html#GUC-TCP-USER-TIMEOUT">tcp_user_timeout</a> to
        control the server's <acronym class="acronym">TCP</acronym> timeout (Ryohei Nagaura)
       </p></li><li class="listitem"><p>
        Allow control of the minimum and maximum <acronym class="acronym">SSL</acronym>
        protocol versions (Peter Eisentraut)
       </p><p>
        The server parameters are <a class="xref" href="runtime-config-connection.html#GUC-SSL-MIN-PROTOCOL-VERSION">ssl_min_protocol_version</a> and <a class="xref" href="runtime-config-connection.html#GUC-SSL-MAX-PROTOCOL-VERSION">ssl_max_protocol_version</a>.
       </p></li><li class="listitem"><p>
        Add server parameter <a class="xref" href="runtime-config-preset.html#GUC-SSL-LIBRARY">ssl_library</a> to report
        the <acronym class="acronym">SSL</acronym> library version used by the server
        (Peter Eisentraut)
       </p></li><li class="listitem"><p>
        Add server parameter <a class="xref" href="runtime-config-resource.html#GUC-SHARED-MEMORY-TYPE">shared_memory_type</a>
        to control the type of shared memory to use (Andres Freund)
       </p><p>
        This allows selection of <span class="productname">System V</span>
        shared memory, if desired.
       </p></li></ul></div></div></div><div class="sect3" id="id-1.11.6.5.5.4"><div class="titlepage"><div><div><h4 class="title">E.1.3.2. Streaming Replication and Recovery</h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
       Allow some recovery parameters to be changed with reload (Peter
       Eisentraut)
      </p><p>
       These parameters are <a class="xref" href="runtime-config-wal.html#GUC-ARCHIVE-CLEANUP-COMMAND">archive_cleanup_command</a>,
       <a class="xref" href="runtime-config-replication.html#GUC-PROMOTE-TRIGGER-FILE">promote_trigger_file</a>, <a class="xref" href="runtime-config-wal.html#GUC-RECOVERY-END-COMMAND">recovery_end_command</a>, and <a class="xref" href="runtime-config-replication.html#GUC-RECOVERY-MIN-APPLY-DELAY">recovery_min_apply_delay</a>.
      </p></li><li class="listitem"><p>
       Allow the streaming replication timeout (<a class="xref" href="runtime-config-replication.html#GUC-WAL-SENDER-TIMEOUT">wal_sender_timeout</a>) to be set per connection
       (Takayuki Tsunakawa)
      </p><p>
       Previously, this could only be set cluster-wide.
      </p></li><li class="listitem"><p>
       Add function <a class="link" href="functions-admin.html#FUNCTIONS-RECOVERY-CONTROL" title="9.26.4. Recovery Control Functions"><code class="function">pg_promote()</code></a>
       to promote standbys to primaries (Laurenz Albe, Michaël Paquier)
      </p><p>
       Previously, this operation was only possible by using <a class="xref" href="app-pg-ctl.html" title="pg_ctl"><span class="refentrytitle"><span class="application">pg_ctl</span></span></a> or creating a trigger file.
      </p></li><li class="listitem"><p>
       Allow replication slots to be copied (Masahiko Sawada)
      </p><p>
       The functions for this are <a class="link" href="functions-admin.html#FUNCTIONS-REPLICATION-TABLE" title="Table 9.88. Replication SQL Functions"><code class="function">pg_copy_physical_replication_slot()</code></a>
       and <code class="function">pg_copy_logical_replication_slot()</code>.
      </p></li><li class="listitem"><p>
       Make <a class="xref" href="runtime-config-replication.html#GUC-MAX-WAL-SENDERS">max_wal_senders</a> not count as part of
       <a class="xref" href="runtime-config-connection.html#GUC-MAX-CONNECTIONS">max_connections</a> (Alexander Kukushkin)
      </p></li><li class="listitem"><p>
       Add an explicit value of <code class="literal">current</code> for <a class="xref" href="runtime-config-wal.html#GUC-RECOVERY-TARGET-TIMELINE">recovery_target_timeline</a> (Peter Eisentraut)
      </p></li><li class="listitem"><p>
       Make recovery fail if a <a class="link" href="sql-prepare-transaction.html" title="PREPARE TRANSACTION">two-phase transaction</a>
       status file is corrupt (Michaël Paquier)
      </p><p>
       Previously, a warning was logged and recovery continued,
       allowing the transaction to be lost.
      </p></li></ul></div></div><div class="sect3" id="id-1.11.6.5.5.5"><div class="titlepage"><div><div><h4 class="title">E.1.3.3. Utility Commands</h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
       Add <a class="xref" href="sql-reindex.html" title="REINDEX"><span class="refentrytitle">REINDEX</span></a> <code class="literal">CONCURRENTLY</code>
       option to allow reindexing without locking out writes (Michaël
       Paquier, Andreas Karlsson, Peter Eisentraut)
      </p><p>
       This is also controlled by the <a class="xref" href="app-reindexdb.html" title="reindexdb"><span class="refentrytitle"><span class="application">reindexdb</span></span></a>
       application's <code class="option">--concurrently</code> option.
      </p></li><li class="listitem"><p>
       Add support for <a class="link" href="ddl-generated-columns.html" title="5.3. Generated Columns">generated
       columns</a> (Peter Eisentraut)
      </p><p>
       The content of generated columns are computed from expressions
       (including references to other columns in the same table)
       rather than being specified by <code class="command">INSERT</code> or
       <code class="command">UPDATE</code> commands.
      </p></li><li class="listitem"><p>
       Add a <code class="literal">WHERE</code> clause
       to <a class="link" href="sql-copy.html" title="COPY"><code class="command">COPY FROM</code></a> to
       control which rows are accepted (Surafel Temesgen)
      </p><p>
       This provides a simple way to filter incoming data.
      </p></li><li class="listitem"><p>
       Allow enumerated values to be added more flexibly
       (Andrew Dunstan, Tom Lane, Thomas Munro)
      </p><p>
       Previously, <a class="link" href="sql-altertype.html" title="ALTER TYPE"><code class="command">ALTER TYPE
       ... ADD VALUE</code></a> could not be called in a transaction
       block, unless it was part of the same transaction that created the
       enumerated type.  Now it can be called in a later transaction, so
       long as the new enumerated value is not referenced until after it is
       committed.
      </p></li><li class="listitem"><p>
       Add commands to end a transaction and start a new one (Peter
       Eisentraut)
      </p><p>
       The commands are <a class="link" href="sql-commit.html" title="COMMIT"><code class="command">COMMIT AND
       CHAIN</code></a>
       and <a class="link" href="sql-rollback.html" title="ROLLBACK"><code class="command">ROLLBACK AND
       CHAIN</code></a>.
      </p></li><li class="listitem"><p>
       Add <a class="xref" href="sql-vacuum.html" title="VACUUM"><span class="refentrytitle">VACUUM</span></a> and <code class="command">CREATE
       TABLE</code> options to prevent <code class="command">VACUUM</code>
       from truncating trailing empty pages (Takayuki Tsunakawa)
      </p><p>
       These options are <code class="varname">vacuum_truncate</code> and
       <code class="varname">toast.vacuum_truncate</code>.  Use of these options
       reduces <code class="command">VACUUM</code>'s locking requirements, but
       prevents returning disk space to the operating system.
      </p></li><li class="listitem"><p>
       Allow <code class="command">VACUUM</code> to skip index cleanup
       (Masahiko Sawada)
      </p><p>
       This change adds a <code class="command">VACUUM</code> command
       option <code class="literal">INDEX_CLEANUP</code> as well as a table storage
       option <code class="literal">vacuum_index_cleanup</code>.  Use of this option
       reduces the ability to reclaim space and can lead to index bloat,
       but it is helpful when the main goal is to freeze old tuples.
      </p></li><li class="listitem"><p>
       Add the ability to skip <code class="command">VACUUM</code> and
       <code class="command">ANALYZE</code> operations on tables that cannot be
       locked immediately (Nathan Bossart)
      </p><p>
       This option is called <code class="literal">SKIP_LOCKED</code>.
      </p></li><li class="listitem"><p>
       Allow <code class="command">VACUUM</code> and <code class="command">ANALYZE</code>
       to take optional Boolean argument specifications (Masahiko Sawada)
      </p></li><li class="listitem"><p>
       Prevent <a class="xref" href="sql-truncate.html" title="TRUNCATE"><span class="refentrytitle">TRUNCATE</span></a>,
       <code class="command">VACUUM</code> and <code class="command">ANALYZE</code>
       from requesting a lock on
       tables for which the user lacks permission (Michaël Paquier)
      </p><p>
       This prevents unauthorized locking, which could interfere with
       user queries.
      </p></li><li class="listitem"><p>
       Add <a class="xref" href="sql-explain.html" title="EXPLAIN"><span class="refentrytitle">EXPLAIN</span></a> option
       <code class="literal">SETTINGS</code> to output non-default optimizer
       settings (Tomas Vondra)
      </p><p>
       This output can also be obtained when using <a class="xref" href="auto-explain.html" title="F.4. auto_explain">auto_explain</a>
       by setting <code class="varname">auto_explain.log_settings</code>.
      </p></li><li class="listitem"><p>
       Add <code class="literal">OR REPLACE</code> option to
       <a class="xref" href="sql-createaggregate.html" title="CREATE AGGREGATE"><span class="refentrytitle">CREATE AGGREGATE</span></a>
       (Andrew Gierth)
      </p></li><li class="listitem"><p>
       Allow modifications of system catalogs' options using <a class="xref" href="sql-altertable.html" title="ALTER TABLE"><span class="refentrytitle">ALTER TABLE</span></a> (Peter Eisentraut)
      </p><p>
       Modifications of catalogs' <code class="literal">reloptions</code> and
       autovacuum settings are now supported.  (Setting <a class="xref" href="runtime-config-developer.html#GUC-ALLOW-SYSTEM-TABLE-MODS">allow_system_table_mods</a> is still required.)
      </p></li><li class="listitem"><p>
       Use all key columns' names when selecting default constraint
       names for foreign keys (Peter Eisentraut)
      </p><p>
       Previously, only the first column name was included in the constraint
       name, resulting in ambiguity for multi-column foreign keys.
      </p></li></ul></div></div><div class="sect3" id="id-1.11.6.5.5.6"><div class="titlepage"><div><div><h4 class="title">E.1.3.4. Data Types</h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
       Update assorted knowledge about Unicode to match Unicode 12.1.0
       (Peter Eisentraut)
      </p><p>
       This fixes, for example, cases
       where <span class="application">psql</span> would misformat output
       involving combining characters.
      </p></li><li class="listitem"><p>
       Update Snowball stemmer dictionaries with support for new languages
       (Arthur Zakirov)
      </p><p>
       This adds word stemming support for Arabic, Indonesian, Irish,
       Lithuanian, Nepali, and Tamil to <a class="link" href="textsearch.html" title="Chapter 12. Full Text Search">full
       text search</a>.
      </p></li><li class="listitem"><p>
       Allow creation of <a class="link" href="collation.html" title="23.2. Collation Support">collations</a> that report
       string equality for strings that are not bit-wise equal (Peter
       Eisentraut)
      </p><p>
       This feature supports <span class="quote">“<span class="quote">nondeterministic</span>”</span> collations
       that can define case- and accent-agnostic equality comparisons.
       Thus, for example, a case-insensitive uniqueness constraint on a
       text column can be made more easily than before.  This is only
       supported for <acronym class="acronym">ICU</acronym> collations.
      </p></li><li class="listitem"><p>
       Add support for <acronym class="acronym">ICU</acronym> collation attributes on older
       ICU versions (Peter Eisentraut)
      </p><p>
       This allows customization of the collation rules in a consistent way
       across all ICU versions.
      </p></li><li class="listitem"><p>
       Allow data
       type <a class="link" href="datatype-character.html#DATATYPE-CHARACTER-SPECIAL-TABLE" title="Table 8.5. Special Character Types">name</a>
       to more seamlessly be compared to other text types (Tom Lane)
      </p><p>
       Type <code class="type">name</code> now behaves much like a domain over
       type <code class="type">text</code> that has default collation <span class="quote">“<span class="quote">C</span>”</span>.
       This allows cross-type comparisons to be processed more efficiently.
      </p></li></ul></div></div><div class="sect3" id="id-1.11.6.5.5.7"><div class="titlepage"><div><div><h4 class="title">E.1.3.5. Functions</h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
       Add support for the <acronym class="acronym">SQL/JSON</acronym> <a class="link" href="functions-json.html#FUNCTIONS-SQLJSON-PATH" title="9.15.2. The SQL/JSON Path Language">path</a> language
       (Nikita Glukhov, Teodor Sigaev, Alexander Korotkov, Oleg Bartunov,
       Liudmila Mantrova)
      </p><p>
       This allows execution of complex queries on <code class="type">JSON</code>
       values using an <acronym class="acronym">SQL</acronym>-standard language.
      </p></li><li class="listitem"><p>
       Add support for <a class="link" href="functions-math.html#FUNCTIONS-MATH-HYP-TABLE" title="Table 9.8. Hyperbolic Functions">hyperbolic
       functions</a> (Lætitia Avrot)
      </p><p>
       Also add <code class="function">log10()</code> as an alias for
       <code class="function">log()</code>, for standards compliance.
      </p></li><li class="listitem"><p>
       Improve the accuracy of statistical aggregates like <a class="link" href="functions-aggregate.html#FUNCTIONS-AGGREGATE-STATISTICS-TABLE" title="Table 9.56. Aggregate Functions for Statistics"><code class="function">variance()</code></a>
       by using more precise algorithms (Dean Rasheed)
      </p></li><li class="listitem"><p>
       Allow <a class="link" href="functions-datetime.html#FUNCTIONS-DATETIME-TABLE" title="Table 9.31. Date/Time Functions"><code class="function">date_trunc()</code></a>
       to have an additional argument to control the time zone (Vik
       Fearing, Tom Lane)
      </p><p>
       This is faster and simpler than using the <code class="literal">AT TIME
       ZONE</code> clause.
      </p></li><li class="listitem"><p>
       Adjust <a class="link" href="functions-formatting.html#FUNCTIONS-FORMATTING-TABLE" title="Table 9.24. Formatting Functions"><code class="function">to_timestamp()</code></a>/<code class="function">to_date()</code>
       functions to be more forgiving of template mismatches (Artur
       Zakirov, Alexander Korotkov, Liudmila Mantrova)
      </p><p>
       This new behavior more closely matches the
       <span class="productname">Oracle</span> functions of the same name.
      </p></li><li class="listitem"><p>
       Fix assorted bugs in <a class="link" href="functions-xml.html" title="9.14. XML Functions"><acronym class="acronym">XML</acronym> functions</a>
       (Pavel Stehule, Markus Winand, Chapman Flack)
      </p><p>
       Specifically, in <code class="literal">XMLTABLE</code>,
       <code class="function">xpath()</code>, and <code class="function">xmlexists()</code>,
       fix some cases where nothing was output for a node, or an
       unexpected error was thrown, or necessary escaping of XML special
       characters was omitted.
      </p></li><li class="listitem"><p>
       Allow the <code class="literal">BY VALUE</code> clause
       in <code class="function">XMLEXISTS</code> and <code class="function">XMLTABLE</code>
       (Chapman Flack)
      </p><p>
       This SQL-standard clause has no effect
       in <span class="productname">PostgreSQL</span>'s implementation, but it
       was unnecessarily being rejected.
      </p></li><li class="listitem"><p>
       Prevent <a class="link" href="functions-info.html#FUNCTIONS-INFO-SESSION-TABLE" title="Table 9.63. Session Information Functions"><code class="function">current_schema()</code></a>
       and <code class="function">current_schemas()</code> from being run by
       parallel workers, as they are not parallel-safe (Michaël Paquier)
      </p></li><li class="listitem"><p>
       Allow <code class="type">RECORD</code> and <code class="type">RECORD[]</code> to be used
       as column types in a query's column definition list for a <a class="link" href="queries-table-expressions.html#QUERIES-TABLEFUNCTIONS" title="7.2.1.4. Table Functions">table function</a> that is declared
       to return <code class="type">RECORD</code> (Elvis Pranskevichus)
      </p></li></ul></div></div><div class="sect3" id="id-1.11.6.5.5.8"><div class="titlepage"><div><div><h4 class="title">E.1.3.6. <a class="link" href="plpgsql.html" title="Chapter 42. PL/pgSQL - SQL Procedural Language">PL/pgSQL</a></h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
       Allow SQL commands and variables with the same names as those
       commands to be used in the same PL/pgSQL function (Tom Lane)
      </p><p>
       For example, allow a variable called <code class="varname">comment</code> to
       exist in a function that calls
       the <code class="command">COMMENT</code> <acronym class="acronym">SQL</acronym> command.
       Previously this combination caused a parse error.
      </p></li><li class="listitem"><p>
       Add new optional warning and error checks to PL/pgSQL (Pavel
       Stehule)
      </p><p>
       The new checks allow for run-time validation of
       <code class="literal">INTO</code> column counts and single-row results.
      </p></li></ul></div></div><div class="sect3" id="id-1.11.6.5.5.9"><div class="titlepage"><div><div><h4 class="title">E.1.3.7. Client Interfaces</h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
       Add connection parameter <a class="xref" href="libpq-connect.html#LIBPQ-TCP-USER-TIMEOUT">tcp_user_timeout</a>
       to control <span class="application">libpq</span>'s <acronym class="acronym">TCP</acronym>
       timeout (Ryohei Nagaura)
      </p></li><li class="listitem"><p>
       Allow <span class="application">libpq</span> (and thus
       <span class="application">psql</span>) to report only the
       <code class="literal">SQLSTATE</code> value in error messages (Didier Gautheron)
      </p></li><li class="listitem"><p>
       Add <span class="application">libpq</span>
       function <a class="link" href="libpq-misc.html#LIBPQ-PQRESULTMEMORYSIZE"><code class="function">PQresultMemorySize()</code></a>
       to report the memory used by a query result (Lars Kanis, Tom Lane)
      </p></li><li class="listitem"><p>
       Remove the no-display/debug flag from <span class="application">libpq</span>'s
       <code class="literal">options</code> connection parameter (Peter Eisentraut)
      </p><p>
       This allows this parameter to be set by
       <span class="application">postgres_fdw</span>.
      </p></li><li class="listitem"><p>
       Allow <a class="xref" href="app-ecpg.html" title="ecpg"><span class="refentrytitle"><span class="application">ecpg</span></span></a> to create variables of data type
       <code class="type">bytea</code> (Ryo Matsumura)
      </p><p>
       This allows ECPG clients to interact with <code class="type">bytea</code> data
       directly, rather than using an encoded form.
      </p></li><li class="listitem"><p>
       Add <code class="command">PREPARE AS</code> support to
       <span class="productname">ECPG</span> (Ryo Matsumura)
      </p></li></ul></div></div><div class="sect3" id="id-1.11.6.5.5.10"><div class="titlepage"><div><div><h4 class="title">E.1.3.8. Client Applications</h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
       Allow <a class="xref" href="app-vacuumdb.html" title="vacuumdb"><span class="refentrytitle"><span class="application">vacuumdb</span></span></a> to select tables for vacuum
       based on their wraparound horizon (Nathan Bossart)
      </p><p>
       The options are <code class="option">--min-xid-age</code> and
       <code class="option">--min-mxid-age</code>.
      </p></li><li class="listitem"><p>
       Allow <span class="application">vacuumdb</span> to disable waiting for locks
       or skipping all-visible pages (Nathan Bossart)
      </p><p>
       The options are <code class="option">--skip-locked</code> and
       <code class="option">--disable-page-skipping</code>.
      </p></li><li class="listitem"><p>
       Add colorization to the output of command-line utilities (Peter
       Eisentraut)
      </p><p>
       This is enabled by setting the environment variable
       <code class="envar">PG_COLOR</code> to <code class="literal">always</code>
       or <code class="literal">auto</code>.  The specific colors used can be
       adjusted by setting the environment variable
       <code class="envar">PG_COLORS</code>, using ANSI escape codes for colors.
       For example, the default behavior is equivalent to
       <code class="literal">PG_COLORS="error=01;31:warning=01;35:locus=01"</code>.
      </p></li></ul></div><div class="sect4" id="id-1.11.6.5.5.10.3"><div class="titlepage"><div><div><h5 class="title">E.1.3.8.1. <a class="xref" href="app-psql.html" title="psql"><span class="refentrytitle"><span class="application">psql</span></span></a></h5></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
        Add <acronym class="acronym">CSV</acronym> table output mode in
        <span class="application">psql</span> (Daniel Vérité)
       </p><p>
        This is controlled by <code class="command">\pset format csv</code> or the
        command-line <code class="option">--csv</code> option.
       </p></li><li class="listitem"><p>
        Show the manual page <acronym class="acronym">URL</acronym> in
        <span class="application">psql</span>'s <code class="command">\help</code> output
        for a SQL command (Peter Eisentraut)
       </p></li><li class="listitem"><p>
        Display the <acronym class="acronym">IP</acronym> address in
        <span class="application">psql</span>'s <code class="command">\conninfo</code>
        (Fabien Coelho)
       </p></li><li class="listitem"><p>
        Improve tab completion of <code class="command">CREATE TABLE</code>,
        <code class="command">CREATE TRIGGER</code>,
        <code class="command">CREATE EVENT TRIGGER</code>,
        <code class="command">ANALYZE</code>, <code class="command">EXPLAIN</code>,
        <code class="command">VACUUM</code>, <code class="command">ALTER TABLE</code>,
        <code class="command">ALTER INDEX</code>, <code class="command">ALTER DATABASE</code>,
        and <code class="command">ALTER INDEX ALTER COLUMN</code>
        (Dagfinn Ilmari Mannsåker, Tatsuro Yamada, Michaël Paquier,
        Tom Lane, Justin Pryzby)
       </p></li></ul></div></div><div class="sect4" id="id-1.11.6.5.5.10.4"><div class="titlepage"><div><div><h5 class="title">E.1.3.8.2. <a class="link" href="pgbench.html" title="pgbench"><span class="application">pgbench</span></a></h5></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
        Allow values produced by queries to be assigned
        to <span class="application">pgbench</span> variables (Fabien Coelho,
        Álvaro Herrera)
       </p><p>
        The command for this is <code class="command">\gset</code>.
       </p></li><li class="listitem"><p>
        Improve precision of <span class="application">pgbench</span>'s
        <code class="option">--rate</code> option (Tom Lane)
       </p></li><li class="listitem"><p>
        Improve <span class="application">pgbench</span>'s error reporting with
        clearer messages and return codes (Peter Eisentraut)
       </p></li></ul></div></div></div><div class="sect3" id="id-1.11.6.5.5.11"><div class="titlepage"><div><div><h4 class="title">E.1.3.9. Server Applications</h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
       Allow control of log file rotation via <a class="xref" href="app-pg-ctl.html" title="pg_ctl"><span class="refentrytitle"><span class="application">pg_ctl</span></span></a>
       (Kyotaro Horiguchi, Alexander Kuzmenkov, Alexander Korotkov)
      </p><p>
       Previously, this was only possible via an <acronym class="acronym">SQL</acronym>
       function or a process signal.
      </p></li><li class="listitem"><p>
       Properly detach the new server process
       during <code class="literal"><span class="application">pg_ctl</span> start</code>
       (Paul Guo)
      </p><p>
       This prevents the server from being shut down if the shell script
       that invoked <span class="application">pg_ctl</span> is interrupted later.
      </p></li><li class="listitem"><p>
       Allow <a class="xref" href="pgupgrade.html" title="pg_upgrade"><span class="refentrytitle"><span class="application">pg_upgrade</span></span></a> to use the file system's cloning
       feature, if there is one (Peter Eisentraut)
      </p><p>
       The <code class="option">--clone</code> option has the advantages of
       <code class="option">--link</code>, while preventing the old cluster from
       being changed after the new cluster has started.
      </p></li><li class="listitem"><p>
       Allow specification of the socket directory to use
       in <span class="application">pg_upgrade</span> (Daniel Gustafsson)
      </p><p>
       This is controlled by <code class="option">--socketdir</code>; the default
       is the current directory.
      </p></li><li class="listitem"><p>
       Allow <a class="xref" href="app-pgchecksums.html" title="pg_checksums"><span class="refentrytitle"><span class="application">pg_checksums</span></span></a> to disable fsync operations
       (Michaël Paquier)
      </p><p>
       This is controlled by the <code class="option">--no-sync</code> option.
      </p></li><li class="listitem"><p>
       Allow <a class="xref" href="app-pgrewind.html" title="pg_rewind"><span class="refentrytitle"><span class="application">pg_rewind</span></span></a> to disable fsync operations
       (Michaël Paquier)
      </p></li><li class="listitem"><p>
       Fix <a class="xref" href="pgtestfsync.html" title="pg_test_fsync"><span class="refentrytitle"><span class="application">pg_test_fsync</span></span></a> to report accurate
       <code class="literal">open_datasync</code> durations on
       <span class="productname">Windows</span> (Laurenz Albe)
      </p></li></ul></div><div class="sect4" id="id-1.11.6.5.5.11.3"><div class="titlepage"><div><div><h5 class="title">E.1.3.9.1. <a class="link" href="app-pgdump.html" title="pg_dump"><span class="application">pg_dump</span></a>,
     <a class="link" href="app-pg-dumpall.html" title="pg_dumpall"><span class="application">pg_dumpall</span></a>,
     <a class="link" href="app-pgrestore.html" title="pg_restore"><span class="application">pg_restore</span></a></h5></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
        When <span class="application">pg_dump</span> emits data
        with <code class="command">INSERT</code> commands rather
        than <code class="command">COPY</code>, allow more than one data row to be
        included in each <code class="command">INSERT</code> (Surafel Temesgen,
        David Rowley)
       </p><p>
        The option controlling this is <code class="option">--rows-per-insert</code>.
       </p></li><li class="listitem"><p>
        Allow <span class="application">pg_dump</span> to emit <code class="command">INSERT
        ... ON CONFLICT DO NOTHING</code> (Surafel Temesgen)
       </p><p>
        This avoids conflict failures during restore.
        The option is <code class="option">--on-conflict-do-nothing</code>.
       </p></li><li class="listitem"><p>
        Decouple the order of operations in a
        parallel <span class="application">pg_dump</span> from the order used by
        a subsequent parallel <span class="application">pg_restore</span> (Tom
        Lane)
       </p><p>
        This allows <span class="application">pg_restore</span> to perform
        more-fully-parallelized parallel restores, especially in cases
        where the original dump was not done in parallel.  Scheduling of a
        parallel <span class="application">pg_dump</span> is also somewhat
        improved.
       </p></li><li class="listitem"><p>
        Allow the <a class="xref" href="runtime-config-client.html#GUC-EXTRA-FLOAT-DIGITS">extra_float_digits</a> setting to be
        specified for <span class="application">pg_dump</span> and
        <span class="application">pg_dumpall</span> (Andrew Dunstan)
       </p><p>
        This is primarily useful for making dumps that are exactly
        comparable across different source server versions.  It is not
        recommended for normal use, as it may result in loss of precision
        when the dump is restored.
       </p></li><li class="listitem"><p>
        Add <code class="option">--exclude-database</code> option to
        <span class="application">pg_dumpall</span> (Andrew Dunstan)
       </p></li></ul></div></div></div><div class="sect3" id="id-1.11.6.5.5.12"><div class="titlepage"><div><div><h4 class="title">E.1.3.10. Source Code</h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
       Add <a class="xref" href="sql-create-access-method.html" title="CREATE ACCESS METHOD"><span class="refentrytitle">CREATE ACCESS METHOD</span></a> command to create
       new table types (Andres Freund, Haribabu Kommi, Álvaro Herrera,
       Alexander Korotkov, Dmitry Dolgov)
      </p><p>
       This enables the development of new <a class="link" href="tableam.html" title="Chapter 60. Table Access Method Interface Definition">table
       access methods</a>, which can optimize storage for different
       use cases.  The existing <code class="literal">heap</code> access method
       remains the default.
      </p></li><li class="listitem"><p>
        Add <a class="link" href="xfunc-optimization.html" title="37.11. Function Optimization Information">planner support
        function</a> interfaces to improve optimizer estimates,
        inlining, and indexing for functions (Tom Lane)
       </p><p>
        This allows extensions to create planner support functions that
        can provide function-specific selectivity, cost, and row-count
        estimates that can depend on the function's arguments.  Support
        functions can also supply simplified representations and index
        conditions, greatly expanding optimization possibilities.
       </p></li><li class="listitem"><p>
       Simplify renumbering manually-assigned OIDs, and establish a new
       project policy for management of such OIDs (John Naylor, Tom Lane)
      </p><p>
       Patches that manually assign OIDs for new built-in objects (such as
       new functions) should now randomly choose OIDs in the range
       8000—9999.  At the end of a development cycle, the OIDs used
       by committed patches will be renumbered down to lower numbers,
       currently somewhere in the 4<em class="replaceable"><code>xxx</code></em> range,
       using the new <a class="link" href="system-catalog-initial-data.html#SYSTEM-CATALOG-OID-ASSIGNMENT" title="69.2.2. OID Assignment"><code class="command">renumber_oids.pl</code></a>
       script.  This approach should greatly reduce the odds of OID
       collisions between different in-process patches.
      </p><p>
       While there is no specific policy reserving any OIDs for external
       use, it is recommended that forks and other projects needing
       private manually-assigned OIDs use numbers in the high
       7<em class="replaceable"><code>xxx</code></em> range.  This will avoid conflicts
       with recently-merged patches, and it should be a long time before
       the core project reaches that range.
      </p></li><li class="listitem"><p>
       Build <span class="productname">Cygwin</span> binaries using dynamic
       instead of static libraries (Marco Atzeri)
      </p></li><li class="listitem"><p>
       Remove <span class="application">configure</span> switch
       <code class="option">--disable-strong-random</code> (Michaël Paquier)
      </p><p>
       A strong random-number source is now required.
      </p></li><li class="listitem"><p>
       <code class="function">printf</code>-family functions, as well
       as <code class="function">strerror</code>
       and <code class="function">strerror_r</code>, now behave uniformly across
       platforms within Postgres code (Tom Lane)
      </p><p>
       Notably, <code class="function">printf</code>
       understands <code class="literal">%m</code> everywhere; on
       Windows, <code class="function">strerror</code> copes with Winsock error
       codes (it used to do so in backend but not frontend code);
       and <code class="function">strerror_r</code> always follows the GNU return
       convention.
      </p></li><li class="listitem"><p>
       Require a C99-compliant compiler, and <acronym class="acronym">MSVC</acronym>
       2013 or later on <span class="productname">Windows</span> (Andres Freund)
      </p></li><li class="listitem"><p>
       Use <span class="application">pandoc</span>,
       not <span class="application">lynx</span>, for generating plain-text
       documentation output files (Peter Eisentraut)
      </p><p>
       This affects only the <code class="filename">INSTALL</code> file generated
       during <code class="literal">make dist</code> and the seldom-used
       plain-text <code class="filename">postgres.txt</code> output file.
       Pandoc produces better output than lynx and avoids some
       locale/encoding issues.  Pandoc version 1.13 or later is required.
      </p></li><li class="listitem"><p>
       Support use of images in the <span class="productname">PostgreSQL</span>
       documentation (Jürgen Purtz)
      </p></li></ul></div></div><div class="sect3" id="id-1.11.6.5.5.13"><div class="titlepage"><div><div><h4 class="title">E.1.3.11. Additional Modules</h4></div></div></div><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
       Allow <code class="literal">ORDER BY</code> sorts
       and <code class="literal">LIMIT</code> clauses to be pushed
       to <a class="xref" href="postgres-fdw.html" title="F.33. postgres_fdw">postgres_fdw</a> foreign servers in more
       cases (Etsuro Fujita)
      </p></li><li class="listitem"><p>
       Improve optimizer cost accounting for
       <span class="application">postgres_fdw</span> queries (Etsuro Fujita)
      </p></li><li class="listitem"><p>
       Properly honor <code class="literal">WITH CHECK OPTION</code> on views
       that reference <span class="application">postgres_fdw</span> tables
       (Etsuro Fujita)
      </p><p>
       While <code class="literal">CHECK OPTION</code>s on
       <span class="application">postgres_fdw</span> tables are ignored (because
       the reference is foreign), views on such tables are considered
       local, so this change enforces <code class="literal">CHECK OPTION</code>s
       on them.  Previously, only <code class="command">INSERT</code>s and
       <code class="command">UPDATE</code>s with <code class="literal">RETURNING</code>
       clauses that returned <code class="literal">CHECK OPTION</code> values
       were validated.
      </p></li><li class="listitem"><p>
       Allow <a class="link" href="pgstatstatements.html" title="F.29. pg_stat_statements"><code class="function">pg_stat_statements_reset()</code></a>
       to be more granular (Haribabu Kommi, Amit Kapila)
      </p><p>
       The function now allows reset of statistics for specific databases,
       users, and queries.
      </p></li><li class="listitem"><p>
       Allow control of the <a class="xref" href="auto-explain.html" title="F.4. auto_explain">auto_explain</a> log level
       (Tom Dunstan, Andrew Dunstan)
      </p><p>
       The default is <code class="literal">LOG</code>.
      </p></li><li class="listitem"><p>
       Update <a class="xref" href="unaccent.html" title="F.43. unaccent">unaccent</a> rules with new
       punctuation and symbols (Hugh Ranalli, Michaël Paquier)
      </p></li><li class="listitem"><p>
       Allow <span class="application">unaccent</span> to handle some accents
       encoded as combining characters (Hugh Ranalli)
      </p></li><li class="listitem"><p>
       Allow <span class="application">unaccent</span> to remove accents from
       Greek characters (Tasos Maschalidis)
      </p></li><li class="listitem"><p>
       Add a parameter to
       <a class="xref" href="amcheck.html" title="F.2. amcheck">amcheck</a>'s <code class="function">bt_index_parent_check()</code>
       function to check each index tuple from the root of the tree
       (Peter Geoghegan)
      </p></li><li class="listitem"><p>
       Improve <a class="xref" href="oid2name.html" title="oid2name"><span class="refentrytitle">oid2name</span></a> and <a class="xref" href="vacuumlo.html" title="vacuumlo"><span class="refentrytitle"><span class="application">vacuumlo</span></span></a>
       option handling to match other commands (Tatsuro Yamada)
      </p></li></ul></div></div></div><div class="sect2" id="RELEASE-12-ACKNOWLEDGEMENTS"><div class="titlepage"><div><div><h3 class="title">E.1.4. Acknowledgments</h3></div></div></div><p>
    The following individuals (in alphabetical order) have contributed to this
    release as patch authors, committers, reviewers, testers, or reporters of
    issues.
   </p><table border="0" summary="Simple list" class="simplelist"><tr><td>Abhijit Menon-Sen</td></tr><tr><td>Achilleas Mantzios</td></tr><tr><td>Adam Berlin</td></tr><tr><td>Adam Bielanski</td></tr><tr><td>Aditya Toshniwal</td></tr><tr><td>Adrien Nayrat</td></tr><tr><td>Alan Jackson</td></tr><tr><td>Albert Schabhuetl</td></tr><tr><td>Aleksander Alekseev</td></tr><tr><td>Alex Aktsipetrov</td></tr><tr><td>Alex Kliukin</td></tr><tr><td>Alex Macy</td></tr><tr><td>Alexander Korotkov</td></tr><tr><td>Alexander Kukushkin</td></tr><tr><td>Alexander Kuzmenkov</td></tr><tr><td>Alexander Lakhin</td></tr><tr><td>Alexandra Ryzhevich</td></tr><tr><td>Alexey Bashtanov</td></tr><tr><td>Alexey Ermakov</td></tr><tr><td>Alexey Kondratov</td></tr><tr><td>Alexey Kryuchkov</td></tr><tr><td>Alexey Stepanov</td></tr><tr><td>Allison Kaptur</td></tr><tr><td>Álvaro Herrera</td></tr><tr><td>Alyssa Ross</td></tr><tr><td>Amit Kapila</td></tr><tr><td>Amit Khandekar</td></tr><tr><td>Amit Langote</td></tr><tr><td>Amul Sul</td></tr><tr><td>Anastasia Lubennikova</td></tr><tr><td>André Hänsel</td></tr><tr><td>Andrea Gelmini</td></tr><tr><td>Andreas Joseph Krogh</td></tr><tr><td>Andreas Karlsson</td></tr><tr><td>Andreas Kunert</td></tr><tr><td>Andreas Scherbaum</td></tr><tr><td>Andreas Seltenreich</td></tr><tr><td>Andrei Yahorau</td></tr><tr><td>Andres Freund</td></tr><tr><td>Andrew Dunstan</td></tr><tr><td>Andrew Fletcher</td></tr><tr><td>Andrew Gierth</td></tr><tr><td>Andrew Krasichkov</td></tr><tr><td>Andrey Borodin</td></tr><tr><td>Andrey Klychkov</td></tr><tr><td>Andrey Lepikhov</td></tr><tr><td>Andy Abelisto</td></tr><tr><td>Anthony Greene</td></tr><tr><td>Anthony Skorski</td></tr><tr><td>Antonin Houska</td></tr><tr><td>Arne Roland</td></tr><tr><td>Arseny Sher</td></tr><tr><td>Arthur Zakirov</td></tr><tr><td>Ash Marath</td></tr><tr><td>Ashutosh Bapat</td></tr><tr><td>Ashutosh Sharma</td></tr><tr><td>Ashwin Agrawal</td></tr><tr><td>Aya Iwata</td></tr><tr><td>Bartosz Polnik</td></tr><tr><td>Basil Bourque</td></tr><tr><td>Bernd Helmle</td></tr><tr><td>Brad DeJong</td></tr><tr><td>Brigitte Blanc-Lafay</td></tr><tr><td>Bruce Klein</td></tr><tr><td>Bruce Momjian</td></tr><tr><td>Bruno Wolff</td></tr><tr><td>Chapman Flack</td></tr><tr><td>Chen Huajun</td></tr><tr><td>Chris Travers</td></tr><tr><td>Chris Wilson</td></tr><tr><td>Christian Hofstaedtler</td></tr><tr><td>Christoph Berg</td></tr><tr><td>Christoph Moench-Tegeder</td></tr><tr><td>Clemens Ladisch</td></tr><tr><td>Colm McHugh</td></tr><tr><td>Corey Huinker</td></tr><tr><td>Craig Ringer</td></tr><tr><td>Dagfinn Ilmari Mannsåker</td></tr><tr><td>Daisuke Higuchi</td></tr><tr><td>Daniel Fiori</td></tr><tr><td>Daniel Gustafsson</td></tr><tr><td>Daniel Vérité</td></tr><tr><td>Daniel Westermann</td></tr><tr><td>Daniel Wilches</td></tr><tr><td>Darafei Praliaskouski</td></tr><tr><td>Daryl Waycott</td></tr><tr><td>Dave Cramer</td></tr><tr><td>David Binderman</td></tr><tr><td>David Fetter</td></tr><tr><td>David G. Johnston</td></tr><tr><td>David Rowley</td></tr><tr><td>David Steele</td></tr><tr><td>Davy Machado</td></tr><tr><td>Dean Rasheed</td></tr><tr><td>Derek Hans</td></tr><tr><td>Derek Nelson</td></tr><tr><td>Devrim Gündüz</td></tr><tr><td>Dian Fay</td></tr><tr><td>Didier Gautheron</td></tr><tr><td>Dilip Kumar</td></tr><tr><td>Dmitry Dolgov</td></tr><tr><td>Dmitry Marakasov</td></tr><tr><td>Dmitry Molotkov</td></tr><tr><td>Dmitry Shalashov</td></tr><tr><td>Don Seiler</td></tr><tr><td>Donald Dong</td></tr><tr><td>Doug Rady</td></tr><tr><td>Edmund Horner</td></tr><tr><td>Eduards Bezverhijs</td></tr><tr><td>Elvis Pranskevichus</td></tr><tr><td>Emanuel Araújo</td></tr><tr><td>Emre Hasegeli</td></tr><tr><td>Eric Cyr</td></tr><tr><td>Erik Rijkers</td></tr><tr><td>Ertugrul Kahveci</td></tr><tr><td>Etsuro Fujita</td></tr><tr><td>Eugen Konkov</td></tr><tr><td>Euler Taveira</td></tr><tr><td>Fabien Coelho</td></tr><tr><td>Fabrízio de Royes Mello</td></tr><tr><td>Feike Steenbergen</td></tr><tr><td>Filip Rembialkowski</td></tr><tr><td>Gaby Schilders</td></tr><tr><td>Geert Lobbestael</td></tr><tr><td>George Tarasov</td></tr><tr><td>Georgios Kokolatos</td></tr><tr><td>Gianni Ciolli</td></tr><tr><td>Gilles Darold</td></tr><tr><td>Greg Stark</td></tr><tr><td>Grigory Smolkin</td></tr><tr><td>Guillaume Lelarge</td></tr><tr><td>Gunnlaugur Thor Briem</td></tr><tr><td>Gurjeet Singh</td></tr><tr><td>Hadi Moshayedi</td></tr><tr><td>Hailong Li</td></tr><tr><td>Hans Buschmann</td></tr><tr><td>Haribabu Kommi</td></tr><tr><td>Haruka Takatsuka</td></tr><tr><td>Hayato Kuroda</td></tr><tr><td>Heikki Linnakangas</td></tr><tr><td>Hironobu Suzuki</td></tr><tr><td>Hubert Lubaczewski</td></tr><tr><td>Hugh Ranalli</td></tr><tr><td>Ian Barwick</td></tr><tr><td>Ibrar Ahmed</td></tr><tr><td>Ildar Musin</td></tr><tr><td>Insung Moon</td></tr><tr><td>Ioseph Kim</td></tr><tr><td>Isaac Morland</td></tr><tr><td>Ivan Panchenko</td></tr><tr><td>Jack Kelly</td></tr><tr><td>Jacob Champion</td></tr><tr><td>Jaime Casanova</td></tr><tr><td>Jakob Egger</td></tr><tr><td>Jakub Glapa</td></tr><tr><td>Jakub Janecek</td></tr><tr><td>James Coleman</td></tr><tr><td>James Inform</td></tr><tr><td>James Robinson</td></tr><tr><td>James Sewell</td></tr><tr><td>James Tomson</td></tr><tr><td>Jan Chochol</td></tr><tr><td>Jaroslav Sivy</td></tr><tr><td>Jean-Christophe Arnu</td></tr><tr><td>Jean-Marc Voillequin</td></tr><tr><td>Jean-Pierre Pelletier</td></tr><tr><td>Jeevan Chalke</td></tr><tr><td>Jeevan Ladhe</td></tr><tr><td>Jeff Davis</td></tr><tr><td>Jeff Janes</td></tr><tr><td>Jeremy Evans</td></tr><tr><td>Jeremy Schneider</td></tr><tr><td>Jeremy Smith</td></tr><tr><td>Jerry Jelinek</td></tr><tr><td>Jesper Pedersen</td></tr><tr><td>Jianing Yang</td></tr><tr><td>Jie Zhang</td></tr><tr><td>Jim Nasby</td></tr><tr><td>Jimmy Yih</td></tr><tr><td>Joe Conway</td></tr><tr><td>Joe Wildish</td></tr><tr><td>Joerg Sonnenberger</td></tr><tr><td>John Klann</td></tr><tr><td>John Naylor</td></tr><tr><td>Jonah Harris</td></tr><tr><td>Jonathan S. Katz</td></tr><tr><td>Jorge Gustavo Rocha</td></tr><tr><td>José Arthur Benetasso Villanova</td></tr><tr><td>Joshua D. Drake</td></tr><tr><td>Juan José Santamaría Flecha</td></tr><tr><td>Julian Hsiao</td></tr><tr><td>Julian Markwort</td></tr><tr><td>Julian Schauder</td></tr><tr><td>Julien Rouhaud</td></tr><tr><td>Jürgen Purtz</td></tr><tr><td>Jürgen Strobel</td></tr><tr><td>Justin Pryzby</td></tr><tr><td>Kaiting Chen</td></tr><tr><td>Karen Huddleston</td></tr><tr><td>Karl Czajkowski</td></tr><tr><td>Karl O. Pinc</td></tr><tr><td>Keiichi Hirobe</td></tr><tr><td>Keith Fiske</td></tr><tr><td>Ken Tanzer</td></tr><tr><td>Kenji Uno</td></tr><tr><td>Kevin Grittner</td></tr><tr><td>Kevin Hale Boyes</td></tr><tr><td>Kieran McCusker</td></tr><tr><td>Kirk Jamison</td></tr><tr><td>Kohei KaiGai</td></tr><tr><td>Konstantin Knizhnik</td></tr><tr><td>Konstantin Kuznetsov</td></tr><tr><td>Kristjan Tammekivi</td></tr><tr><td>Kuntal Ghosh</td></tr><tr><td>Kyle Samson</td></tr><tr><td>Kyotaro Horiguchi</td></tr><tr><td>Lætitia Avrot</td></tr><tr><td>Lars Kanis</td></tr><tr><td>Laurenz Albe</td></tr><tr><td>Lim Myungkyu</td></tr><tr><td>Liu Huailing</td></tr><tr><td>Liudmila Mantrova</td></tr><tr><td>Lloyd Albin</td></tr><tr><td>Luca Ferrari</td></tr><tr><td>Luis M. Carril</td></tr><tr><td>Lukas Eder</td></tr><tr><td>Lukas Fittl</td></tr><tr><td>Madelaine Thibaut</td></tr><tr><td>Madeleine Thompson</td></tr><tr><td>Magnus Hagander</td></tr><tr><td>Mahendra Singh</td></tr><tr><td>Mai Peng</td></tr><tr><td>Maksim Milyutin</td></tr><tr><td>Maksym Boguk</td></tr><tr><td>Malthe Borch</td></tr><tr><td>Manuel Rigger</td></tr><tr><td>Marco Atzeri</td></tr><tr><td>Marco Slot</td></tr><tr><td>Marina Polyakova</td></tr><tr><td>Mario De Frutos Dieguez</td></tr><tr><td>Marius Timmer</td></tr><tr><td>Mark Chambers</td></tr><tr><td>Mark Dilger</td></tr><tr><td>Marko Tiikkaja</td></tr><tr><td>Markus Winand</td></tr><tr><td>Martín Marqués</td></tr><tr><td>Masahiko Sawada</td></tr><tr><td>Masao Fujii</td></tr><tr><td>Mateusz Guzik</td></tr><tr><td>Mathias Brossard</td></tr><tr><td>Matt Williams</td></tr><tr><td>Matthias Otterbach</td></tr><tr><td>Matvey Arye</td></tr><tr><td>Melanie Plageman</td></tr><tr><td>Mi Tar</td></tr><tr><td>Michael Banck</td></tr><tr><td>Michael Davidson</td></tr><tr><td>Michael Meskes</td></tr><tr><td>Michael Paquier</td></tr><tr><td>Michael Vitale</td></tr><tr><td>Michel Pelletier</td></tr><tr><td>Mikalai Keida</td></tr><tr><td>Mike Palmiotto</td></tr><tr><td>Mithun Cy</td></tr><tr><td>Morgan Owens</td></tr><tr><td>Murat Kabilov</td></tr><tr><td>Nathan Bossart</td></tr><tr><td>Nawaz Ahmed</td></tr><tr><td>Neeraj Kumar</td></tr><tr><td>Nick Barnes</td></tr><tr><td>Nico Williams</td></tr><tr><td>Nikita Glukhov</td></tr><tr><td>Nikolay Shaplov</td></tr><tr><td>Ning Yu</td></tr><tr><td>Nishant Fnu</td></tr><tr><td>Noah Misch</td></tr><tr><td>Norbert Benkocs</td></tr><tr><td>Noriyoshi Shinoda</td></tr><tr><td>Oleg Bartunov</td></tr><tr><td>Oleg Samoilov</td></tr><tr><td>Oleksii Kliukin</td></tr><tr><td>Ondrej Bouda</td></tr><tr><td>Oskari Saarenmaa</td></tr><tr><td>Pan Bian</td></tr><tr><td>Patrick Francelle</td></tr><tr><td>Patrick McHardy</td></tr><tr><td>Paul A. Jungwirth</td></tr><tr><td>Paul Bonaud</td></tr><tr><td>Paul Guo</td></tr><tr><td>Paul Martinez</td></tr><tr><td>Paul Ramsey</td></tr><tr><td>Paul Schaap</td></tr><tr><td>Paul van der Linden</td></tr><tr><td>Pavan Deolasee</td></tr><tr><td>Pavel Oskin</td></tr><tr><td>Pavel Raiskup</td></tr><tr><td>Pavel Stehule</td></tr><tr><td>Peifeng Qiu</td></tr><tr><td>Peter Billen</td></tr><tr><td>Peter Eisentraut</td></tr><tr><td>Peter Geoghegan</td></tr><tr><td>Peter Neave</td></tr><tr><td>Petr Fedorov</td></tr><tr><td>Petr Jelínek</td></tr><tr><td>Petr Slavov</td></tr><tr><td>Petru-Florin Mihancea</td></tr><tr><td>Phil Bayer</td></tr><tr><td>Phil Florent</td></tr><tr><td>Philip Dubé</td></tr><tr><td>Pierre Ducroquet</td></tr><tr><td>Piotr Gabriel Kosinski</td></tr><tr><td>Piotr Stefaniak</td></tr><tr><td>Piotr Wlodarczyk</td></tr><tr><td>Prabhat Sahu</td></tr><tr><td>Quentin Rameau</td></tr><tr><td>Rafael Castro</td></tr><tr><td>Rafia Sabih</td></tr><tr><td>Rahila Syed</td></tr><tr><td>Rajkumar Raghuwanshi</td></tr><tr><td>Rares Salcudean</td></tr><tr><td>Raúl Marín Rodríguez</td></tr><tr><td>Regina Obe</td></tr><tr><td>Renaud Navarro</td></tr><tr><td>Richard Guo</td></tr><tr><td>Rick Otten</td></tr><tr><td>Rikard Falkeborn</td></tr><tr><td>RK Korlapati</td></tr><tr><td>Robbie Harwood</td></tr><tr><td>Robert Haas</td></tr><tr><td>Robert Treat</td></tr><tr><td>Robert Vollmert</td></tr><tr><td>Roger Curley</td></tr><tr><td>Roman Zharkov</td></tr><tr><td>Ronan Dunklau</td></tr><tr><td>Rui Hai Jiang</td></tr><tr><td>Rushabh Lathia</td></tr><tr><td>Ryan Lambert</td></tr><tr><td>Ryo Matsumura</td></tr><tr><td>Ryohei Nagaura</td></tr><tr><td>Ryohei Takahashi</td></tr><tr><td>Samuel Williams</td></tr><tr><td>Sand Stone</td></tr><tr><td>Sanyo Capobiango</td></tr><tr><td>Satoru Koizumi</td></tr><tr><td>Sean Johnston</td></tr><tr><td>Serge Latyntsev</td></tr><tr><td>Sergei Kornilov</td></tr><tr><td>Sergey Pashkov</td></tr><tr><td>Sergio Conde Gómez</td></tr><tr><td>Shawn Debnath</td></tr><tr><td>Shay Rojansky</td></tr><tr><td>Sho Kato</td></tr><tr><td>Shohei Mochizuki</td></tr><tr><td>Shouyu Luo</td></tr><tr><td>Simon Riggs</td></tr><tr><td>Sivasubramanian Ramasubramanian</td></tr><tr><td>Slawomir Chodnicki</td></tr><tr><td>Stas Kelvish</td></tr><tr><td>Stefan Kadow</td></tr><tr><td>Stepan Yankevych</td></tr><tr><td>Stephen Amell</td></tr><tr><td>Stephen Frost</td></tr><tr><td>Steve Rogerson</td></tr><tr><td>Steve Singer</td></tr><tr><td>Steven Winfield</td></tr><tr><td>Surafel Temesgen</td></tr><tr><td>Suraj Kharage</td></tr><tr><td>Suresh Kumar R</td></tr><tr><td>Takayuki Tsunakawa</td></tr><tr><td>Takeshi Ideriha</td></tr><tr><td>Takuma Hoshiai</td></tr><tr><td>Tasos Maschalidis</td></tr><tr><td>Tatsuo Ishii</td></tr><tr><td>Tatsuro Yamada</td></tr><tr><td>Teodor Sigaev</td></tr><tr><td>Thom Brown</td></tr><tr><td>Thomas Munro</td></tr><tr><td>Thomas Poty</td></tr><tr><td>Tillmann Schulz</td></tr><tr><td>Tim Möhlmann</td></tr><tr><td>Timur Birsh</td></tr><tr><td>Tobias Bussmann</td></tr><tr><td>Tom Cassidy</td></tr><tr><td>Tom Dunstan</td></tr><tr><td>Tom Gottfried</td></tr><tr><td>Tom Lane</td></tr><tr><td>Tomas Vondra</td></tr><tr><td>Tushar Ahuja</td></tr><tr><td>Ulf Adams</td></tr><tr><td>Vaishnavi Prabakaran</td></tr><tr><td>Victor Petrovykh</td></tr><tr><td>Victor Wagner</td></tr><tr><td>Victor Yegorov</td></tr><tr><td>Vijaykumar Jain</td></tr><tr><td>Vik Fearing</td></tr><tr><td>Vlad Sterzhanov</td></tr><tr><td>Vladimir Baranoff</td></tr><tr><td>Vladimir Kriukov</td></tr><tr><td>Wu Fei</td></tr><tr><td>Yaroslav Schekin</td></tr><tr><td>Yi Huang</td></tr><tr><td>Yoshikazu Imai</td></tr><tr><td>Yugo Nagata</td></tr><tr><td>Yulian Khodorkovskiy</td></tr><tr><td>Yuming Wang</td></tr><tr><td>YunQiang Su</td></tr><tr><td>Yuri Kurenkov</td></tr><tr><td>Yusuke Egashita</td></tr><tr><td>Yuzuko Hosoya</td></tr><tr><td>Zhou Digoal</td></tr></table></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="release.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="release.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="release-prior.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Appendix E. Release Notes </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> E.2. Prior Releases</td></tr></table></div></body></html>