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

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

  <note>
   <title>Release Date</title>
   <simpara>2017-09-XX</simpara>
   <simpara>CURRENT AS OF 2017-04-22</simpara>
  </note>

  <sect2>
   <title>Overview</title>

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

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

   <itemizedlist>

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

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

  </sect2>

  <sect2>

  <title>Migration to Version 10</title>

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

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

   <itemizedlist>

<listitem>
<!--
Copied here from this commit:
Author: Robert Haas <rhaas@postgresql.org>
2017-04-03 [ea69a0dea] Expand hash indexes more gradually.
-->
<para>
<application>pg_upgrade</>-ed hash indexes from previous major Postgres versions must be rebuilt.
</para>

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

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

<listitem>
<!--<listitem>
Author: Robert Haas <rhaas@postgresql.org>
2016-10-20 [f82ec32ac] Rename "pg_xlog" directory to "pg_wal"
-->
<para>
Rename <filename>pg_xlog</> to <link linkend="wal"><filename>pg_wal</></> (Michael Paquier)
</para>

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

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

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

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2017-03-17 [88e66d193] Rename "pg_clog" directory to "pg_xact".
-->
<para>
Rename transaction status directory <filename>pg_clog</> directory to <filename>pg_xact</>
(Michael Paquier)
</para>
</listitem>

<listitem>
<!--
Author: Andres Freund <andres@anarazel.de>
2017-01-18 [69f4b9c85] Move targetlist SRF handling from expression evaluation 
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-01-18 [f13a1277a] Doc: improve documentation of new SRF-in-tlist behavior.
-->
<para>
Allow <literal>COALESCE</> and <literal>CASE</> to return multiple rows when evaluating
set-returning functions (Andres Freund).  
</para>

<para>
This also prevents conditionals like <literal>CASE</> from controlling the
execution of set-returning functions because set-returning functions
are now executed earlier.
</para>
</listitem>

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

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

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

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

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

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-02-27 [817f2a586] Remove PL/Tcl's "module" facility.
-->
<para>
Remove PL/Tcl's "module" auto-loading facility (Tom Lane)
</para>

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

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2016-12-23 [e13486eba] Remove sql_inheritance <acronym>GUC</>.
-->
<para>
Remove <varname>sql_inheritance</> <acronym>GUC</> (Robert Haas)
</para>

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

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

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-10-12 [64f3524e2] Remove pg_dump/pg_dumpall support for dumping from pre-8
-->
<para>
Remove <application>pg_dump</>/<application>pg_dumpall</> support for dumping from pre-8.0 servers (Tom
Lane)
</para>

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-02-23 [b6aa17e0a] De-support floating-point timestamps.
-->
<para>
Remove support for floating-point datetimes/timestamps (Tom Lane)
</para>

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-10-11 [2f1eaf87e] Drop server support for <acronym>FE/BE</> protocol version 1.0.
-->
<para>
Remove support for client/server protocol version 1.0 (Tom Lane)
</para>

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

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2017-02-13 [7ada2d31f] Remove contrib/tsearch2.
-->
<para>
Remove contrib/tsearch2 (Robert Haas)
</para>

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

<listitem>
<!--
Author: Peter Eisentraut <peter_e@gmx.net>
2017-03-23 [50c956add] Remove createlang and droplang
-->
<para>
Remove createlang and droplang command-line applications (Peter Eisentraut)
</para>
</listitem>

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-10-11 [2b860f52e] Remove "sco" and "unixware" ports.
-->
<para>
Remove <systemitem class="osname">SCO</> and <systemitem class="osname">Unixware</> ports (Tom Lane)
</para>
</listitem>

   </itemizedlist>

  </sect2>

  <sect2>
   <title>Changes</title>

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

   <sect3>
    <title>Server</title>

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

     <itemizedlist>

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

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

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

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

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2017-03-07 [3bc7dafa9] Consider parallel merge joins.
-->
<para>
Allow merge joins to be performed in parallel (Dilip Kumar)
</para>
</listitem>

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

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

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

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

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Indexes</title>

     <itemizedlist>

<listitem>
<!--
Author: Andrew Dunstan <andrew@dunslane.net>
2017-03-31 [e306df7f9] Full Text Search support for <type>JSON</> and <type>JSONB</>
-->
<para>
Add full text search support for <type>JSON</> and <type>JSONB</> (Dmitry Dolgov)
</para>

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-08-23 [77e290682] Create an SP-GiST opclass for inet/cidr.
-->
<para>
Add <acronym>SP-GiST</> index support for <type>INET</> and <type>CIDR</> data types (Emre Hasegeli)
</para>

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

<listitem>
<!--
Author: Teodor Sigaev <teodor@sigaev.ru>
2017-03-23 [218f51584] Reduce page locking in <acronym>GIN</> vacuum
-->
<para>
Reduce page locking during vacuuming of <acronym>GIN</> indexes (Andrey Borodin)
</para>
</listitem>

<listitem>
<!--
Author: Alvaro Herrera <alvherre@alvh.no-ip.org>
2017-04-01 [7526e1022] BRIN auto-summarization
-->
<para>
Cause <acronym>BRIN</> index summarization to happen more aggressively (&Aacute;lvaro
Herrera)
</para>

<para>
Specifically, summarize the previous page range when a new page range is
created.
</para>
</listitem>

<listitem>
<!--
Author: Alvaro Herrera <alvherre@alvh.no-ip.org>
2017-04-01 [c655899ba] BRIN de-summarization
-->
<para>
Add function <function>brin_desummarize_range()</> to remove <acronym>BRIN</> summarization of a
specified range (&Aacute;lvaro Herrera)
</para>

<para>
This allows future <acronym>BRIN</> index summarization to be more compact.  CLARIFY
</para>
</listitem>

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

       <itemizedlist>

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2017-03-14 [c11453ce0] hash: Add write-ahead logging support.
-->
<para>
Add write-ahead logging support to hash indexes (Amit Kapila)
</para>

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

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

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

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2017-02-27 [b0f18cb77] hash: Refactor bucket squeeze code.
Author: Robert Haas <rhaas@postgresql.org>
2017-02-27 [30df93f69] hash: Refactor overflow page allocation.
Author: Robert Haas <rhaas@postgresql.org>
2017-04-03 [ea69a0dea] Expand hash indexes more gradually.
-->
<para>
Improve efficiency of hash index growth (Amit Kapila, Mithun Cy)
</para>
</listitem>

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2017-03-15 [6977b8b7f] Port single-page btree vacuum logic to hash indexes.
-->
<para>
Allow single-page hash pruning (Ashutosh Sharma)
</para>
</listitem>

       </itemizedlist>

      </sect5>

     </sect4>

     <sect4>

      <title>Locking</title>

      <itemizedlist>

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-03-31 [64d4da511] For foreign keys, check <literal>REFERENCES</> privilege only on the
-->
<para>
Only check for <literal>REFERENCES</> permission on referenced tables (Tom Lane)
</para>

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

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

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

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

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

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Optimizer</title>

     <itemizedlist>

<listitem>
<!--
Author: Alvaro Herrera <alvherre@alvh.no-ip.org>
2017-03-24 [7b504eb28] Implement multivariate n-distinct coefficients
Author: Simon Riggs <simon@2ndQuadrant.com>
2017-04-05 [2686ee1b7] Collect and use multi-column dependency stats
-->
<para>
Add the ability to compute a correlation ratio and the number of
distinct values on several columns (Tomas Vondra, David Rowley)
</para>

<para>
New commands are <command><link linkend="SQL-CREATESTATISTICS">CREATE</></>,
<command><link linkend="SQL-ALTERSTATISTICS">ALTER</></>, and
<command><link linkend="SQL-DROPSTATISTICS">DROP STATISTICS</></>.  This is helpful in
estimating query memory usage and ... HOW IS RATIO USED?
</para>
</listitem>

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-01-15 [0777f7a2e] Fix matching of boolean index columns to sort ordering.
-->
<para>
Improve planner matching of boolean indexes (Tom Lane)
</para>
</listitem>

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2017-03-16 [b30fb56b0] postgres_fdw: Push down <literal>FULL JOIN</>s with restriction clau
-->
<para>
Improve optimization of <literal>FULL JOIN</> queries containing subqueries in the
<literal>FROM</> clause (Etsuro Fujita)
</para>
</listitem>

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-01-18 [215b43cdc] Improve RLS planning by marking individual quals with se
-->
<para>
Improve performance of queries referencing row-level security
restrictions (Tom Lane)
</para>

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

     </itemizedlist>

    </sect4>

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

     <itemizedlist>

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

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

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

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

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

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-04-07 [9c7f5229a] Optimize joins when the inner relation can be proven uni
-->
<para>
Use uniqueness guarantees to optimize certain join types (David Rowley)
</para>
</listitem>

<listitem>
<!--
Author: Teodor Sigaev <teodor@sigaev.ru>
2017-03-29 [f90d23d0c] Implement SortSupport for macaddr data type
-->
<para>
Improve sort performance of the macaddr data type (Brandur Leach)
</para>
</listitem>

     </itemizedlist>

    </sect4>

    <sect4>
     <title>Monitoring</title>

     <itemizedlist>

<listitem>
<!--
Author: Peter Eisentraut <peter_e@gmx.net>
2016-11-18 [67dc4ccbb] Add pg_sequences view
-->
<para>
Add <link linkend="view-pg-sequences"><structname>pg_sequences</></> view to show all sequences (Peter Eisentraut)
</para>
</listitem>

<listitem>
<!--
Author: Peter Eisentraut <peter_e@gmx.net>
2016-12-20 [1753b1b02] Add pg_sequence system catalog
-->
<para>
Create a <link linkend="catalog-pg-sequence"><structname>pg_sequence</></> system catalog to store sequence metadata
(Peter Eisentraut)
</para>

<para>
Sequence metadata includes start, increment, etc, which is now
transactional.  Sequence counters are still stored in separate heap
relations.
</para>
</listitem>

<listitem>
<!--
Author: Stephen Frost <sfrost@snowman.net>
2017-03-08 [f9b1a0dd4] Expose explain's SUMMARY option
-->
<para>
Allow explicit control over <command><link linkend="SQL-EXPLAIN">EXPLAIN</></>'s display of planning and execution
time (Stephen Frost)
</para>

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-03-18 [17f8ffa1e] Fix <command>REFRESH MATERIALIZED VIEW</> to report activity to the 
-->
<para>
Properly update the statistics collector during <link linkend="SQL-REFRESHMATERIALIZEDVIEW"><command>REFRESH MATERIALIZED VIEW</></>
(Jim Mlodgenski)
</para>
</listitem>

<listitem>
<!--
Author: Simon Riggs <simon@2ndQuadrant.com>
2017-03-30 [25fff4079] Default monitoring roles
-->
<para>
Add default monitoring roles (Dave Page)
</para>

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

      </itemizedlist>
      
      <sect5>
      <title>Logging</title>

      <itemizedlist>

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

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

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2017-03-16 [befd73c50] Add pg_ls_logdir() and pg_ls_waldir() functions.
-->
<para>
Add functions to return the log and <acronym>WAL</> directory names (Dave Page)
</para>

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

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2017-03-03 [19dc233c3] Add pg_current_logfile() function.
-->
<para>
Add function <link linkend="functions-info-session-table"><function>pg_current_logfile()</></> to read syslog's current stderr and
csvlog output file names (Gilles Darold)
</para>
</listitem>

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

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-03-10 [6ec4c8584] Reduce log verbosity of startup/shutdown for launcher su
-->
<para>
Reduce log chatter about the starting and stopping of launcher
subprocesses (Tom Lane)
</para>

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

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

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

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

      <itemizedlist>

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

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

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

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2017-03-26 [fc70a4b0d] Show more processes in pg_stat_activity.
-->
<para>
Show auxiliary processes and background workers in <structname>pg_stat_activity</>
(Kuntal Ghosh)
</para>

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

<listitem>
<!--
Author: Simon Riggs <simon@2ndQuadrant.com>
2016-09-12 [fc3d4a44e] Identify walsenders in pg_stat_activity
-->
<para>
Display walsender processes in <structname>pg_stat_activity</> (Michael Paquier)
</para>

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

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2017-02-22 [4c728f382] Pass the source text for a parallel query to the workers
-->
<para>
Allow <structname>pg_stat_activity</> to show the source query being executed by parallel workers 
(Rafia Sabih)
</para>
</listitem>

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

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

      </itemizedlist>

      </sect5>
      
    </sect4>

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

     <itemizedlist>

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

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

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

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

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

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

<listitem>
<!--
Author: Magnus Hagander <magnus@hagander.net>
2017-03-22 [6b76f1bb5] Support multiple RADIUS servers
-->
<para>
Support multiple <acronym>RADIUS</> servers (Magnus Hagander)
</para>

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

     </itemizedlist>

    </sect4>

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

     <itemizedlist>

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

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

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

<listitem>
<!--
Author: Simon Riggs <simon@2ndQuadrant.com>
2017-03-06 [21d4e2e20] Reduce lock levels for table storage params related to p
Author: Simon Riggs <simon@2ndQuadrant.com>
2017-04-05 [68ea2b7f9] Reduce lock level for CREATE STATISTICS
-->
<para>
Reduce locking required to change table params (Simon Riggs, Fabr&iacute;zio
Mello)
</para>

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

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

    </itemizedlist>

    </sect4>

    <sect4>
     <title>Reliability</title>

     <itemizedlist>

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

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

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2016-11-21 [a734fd5d1] autovacuum: Drop orphan temp tables more quickly but wit
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-11-27 [dafa0848d] Code review for early drop of orphaned temp relations in
-->
<para>
Remove orphaned temporary tables more aggressively (Robert Haas, Tom Lane)
</para>

<para>
Previously such tables were removed only when necessary. SECTION?
</para>
</listitem>

      </itemizedlist>

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

      <itemizedlist>

<listitem>
<!--
Author: Andres Freund <andres@anarazel.de>
2016-12-22 [6ef2eba3f] Skip checkpoints, archiving on idle systems.
-->
<para>
Prevent checkpoints and <acronym>WAL</> archiving on otherwise-idle systems (Michael
Paquier)
</para>
</listitem>

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

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

<listitem>
<!--
Author: Simon Riggs <simon@2ndQuadrant.com>
2017-04-05 [00b6b6feb] Allow \-\-with-wal-segsize=n up to n=1024MB
-->
<para>
Increase the maximum configurable <acronym>WAL</> size to 1 gigabyte (Beena Emerson)
</para>
</listitem>

      </itemizedlist>
      
      </sect5>

    </sect4>

   </sect3>

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

     <itemizedlist>

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

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

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

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

</para>
</listitem>

<listitem>
<!--
Author: Magnus Hagander <magnus@hagander.net>
2017-01-14 [f6d6d2920] Change default values for backup and replication paramet
-->
<para>
Reduce configuration necessary to perform streaming backup and
replication (Magnus Hagander)
</para>

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

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

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

<listitem>
<!--
Author: Simon Riggs <simon@2ndQuadrant.com>
2017-03-23 [6912acc04] Replication lag tracking for walsenders
-->
<para>
Add columns to <link linkend="monitoring-stats-views-table"><structname>pg_stat_replication</></> to report replication delay times
(Thomas Munro)
</para>

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

<listitem>
<!--
Author: Simon Riggs <simon@2ndQuadrant.com>
2016-09-03 [35250b6ad] New recovery target recovery_target_lsn
-->
<para>
Add specification of a Log Sequence Number (<acronym>LSN</>) stopping point in
<link linkend="recovery-config"><filename>recovery.conf</></> (Michael Paquier)
</para>

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

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

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

<listitem>
<!--
Author: Peter Eisentraut <peter_e@gmx.net>
2016-12-12 [a924c327e] Add support for temporary replication slots
-->
<para>
Allow creation of <link linkend="functions-replication-table">temporary replication slots</> (Petr Jelinek)
</para>

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

<listitem>
<!--
Author: Simon Riggs <simon@2ndQuadrant.com>
2017-03-22 [9b013dc23] Improve performance of replay of AccessExclusiveLocks
-->
<para>
Improve performance of hot standby replay with better tracking of
Access Exclusive locks (Simon Riggs, David Rowley)
</para>
</listitem>

<listitem>
<!--
Author: Simon Riggs <simon@2ndQuadrant.com>
2017-04-04 [728bd991c] Speedup 2PC recovery by skipping two phase state files i
-->
<para>
Speed up two-phase commit recovery performance (Simon Riggs)
</para>
</listitem>

     </itemizedlist>

   </sect3>

   <sect3>
    <title>Queries</title>

     <itemizedlist>

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

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

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

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

     </itemizedlist>

   </sect3>

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

     <itemizedlist>

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

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

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

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

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

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

<listitem>
<!--
Author: Teodor Sigaev <teodor@sigaev.ru>
2017-03-28 [ab89e465c] Altering default privileges on schemas
-->
<para>
Allow <link linkend="SQL-ALTERDEFAULTPRIVILEGES">default permissions</> on schemas (Matheus Oliveira)
</para>

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

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

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-11-10 [279c439c7] Support "COPY view FROM" for views with INSTEAD OF INSER
-->
<para>
Allow <command>COPY view FROM</> on views with <literal>INSTEAD INSERT</> triggers (Haribabu
Kommi)
</para>

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

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

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

<listitem>
<!--<listitem>
Author: Peter Eisentraut <peter_e@gmx.net>
2017-03-06 [583f6c414] Allow dropping multiple functions at once
Author: Peter Eisentraut <peter_e@gmx.net>
2017-03-14 [aefeb6874] Allow referring to functions without arguments when uniq-->
<para>
Allow multiple functions, operators, and aggregates to be dropped with a
single <command>DROP</> command (Peter Eisentraut)
</para>
</listitem>

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

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

<listitem>
<!--
Author: Fujii Masao <fujii@postgresql.org>
2017-03-25 [70adf2fbe] Make VACUUM VERBOSE report the number of skipped frozen 
-->
<para>
Have <link linkend="SQL-VACUUM"><command>VACUUM VERBOSE</></> report the number of skipped frozen pages (Masahiko
Sawada)
</para>

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-01-16 [d43a619c6] Fix check_srf_call_placement() to handle VALUES cases co
-->
<para>
Fix <function>check_srf_call_placement()</> to handle <command>VALUES</> cases correctly (Tom
Lane)
</para>

<para>
NEED TEXT.
</para>
</listitem>

    </itemizedlist>

   </sect3>

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

    <itemizedlist>

<listitem>
<!--
Author: Stephen Frost <sfrost@snowman.net>
2017-03-15 [c7a9fa399] Add support for EUI-64 MAC addresses as macaddr8
-->
<para>
Add support for <acronym>EUI-64</> <acronym>MAC</> addresses as <link linkend="datatype-macaddr8"><type>MACADDR8</></> (Haribabu Kommi)
</para>

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

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

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

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

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

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

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

<listitem>
<!--
Author: Peter Eisentraut <peter_e@gmx.net>
2017-01-17 [323b96aa3] Register missing money operators in system catalogs
-->
<para>
Add <link linkend="datatype-money"><type>MONEY</></> operators for multiplication and division with <type>INT8</> values
(Peter Eisentraut)
</para>
</listitem>

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

    </itemizedlist>

   </sect3>

   <sect3>
    <title>Functions</title>

     <itemizedlist>

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-08-17 [cf9b0fea5] Implement regexp_match(), a simplified alternative to re
-->
<para>
Add simplified <link linkend="functions-posix-regexp"><function>regexp_match()</></> function (Emre Hasegeli)
</para>

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

<listitem>
<!--
Author: Alvaro Herrera <alvherre@alvh.no-ip.org>
2017-03-08 [fcec6caaf] Support XMLTABLE query expression
-->
<para>
Add support for converting <type>XML</>-formatted data into a row set (Pavel
Stehule, &Aacute;lvaro Herrera)
</para>

<para>
This is done by referencing the new <link linkend="functions-xml-processing-xmltable"><function>XMLTABLE</></> function.
</para>
</listitem>

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

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

<listitem>
<!--
Author: Andrew Dunstan <andrew@dunslane.net>
2017-04-06 [cf35346e8] Make json_populate_record and friends operate recursivel
-->
<para>
Improve <link linkend="functions-json-processing-table"><function>json_populate_record</></> and friends operate recursively (Nikita
Glukhov)
</para>

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

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

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

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

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

<listitem>
<!--
Author: Alvaro Herrera <alvherre@alvh.no-ip.org>
2017-01-19 [30bcebbdc] Allow negative years in make_date to represent BC years
-->
<para>
Allow <link linkend="functions-formatting-table"><function>make_date()</></> to interpret negative years as <acronym>BC</> years (&Aacute;lvaro
Herrera)
</para>
</listitem>

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-09-28 [d3cd36a13] Make to_timestamp() and to_date() range-check fields of 
-->
<para>
Have <function>to_timestamp()</> and <function>to_date()</> check input values for validity
(Artur Zakirov)
</para>

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

     </itemizedlist>

   </sect3>

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

    <itemizedlist>

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

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

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-11-08 [1833f1a1c]     Simplify code by getting rid of SPI_push, SPI_pop, SPI_r

-->
<para>
Remove <acronym>SPI</> functions <function>SPI_push()</>, <function>SPI_pop()</>, <function>SPI_restore_connection()</> as
unnecessary (Tom Lane)
</para>

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

    </itemizedlist>

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

    <itemizedlist>

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-11-06 [26abb50c4] Support PL/Tcl functions that return composite types and
-->
<para>
Allow PL/Tcl functions to return composite types and sets (Jim Nasby)
</para>
</listitem>

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-03-11 [b58fd4a9c] Add a "subtransaction" command to PL/Tcl.
-->
<para>
Add a subtransaction command to PL/Tcl (Victor Wagner)
</para>

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

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

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

    </itemizedlist>
   
    </sect4>
    
   </sect3>

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

    <itemizedlist>

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2016-11-03 [274bb2b38] libpq: Allow connection strings and <acronym>URI</>s to specify mult
-->
<para>
Allow libpq to connect to <link linkend="libpq-connect-host">multiple specified</> host names (Robert Haas)
</para>

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

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

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-01-24 [ba005f193] Allow password file name to be specified as a libpq conn
-->
<para>
Allow <link linkend="libpq-connect-passfile">password file name</> to be specified as a libpq connection parameter
(Julian Markwort)
</para>

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-08-16 [a7b5573d6] Remove separate version numbering for ecpg preprocessor.
-->
<para>
ecpg preprocessor version changed from 4.12 to 10 (Tom Lane)
</para>

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

    </itemizedlist>

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

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

      <itemizedlist>

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-03-30 [e984ef586] Support \if ... \elif ... \else ... \endif in psql scrip
-->
<para>
Add conditional branch support to <application>psql</> (Corey Huinker)
</para>

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

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

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

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-04-01 [f833c847b] Allow psql variable substitution to occur in backtick co
-->
<para>
Expand <application>psql</> colon variables when used in backtick-executed contexts (Tom Lane)
</para>

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

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

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-04-02 [5dbc5da11] Fix behavior of psql's \p to agree with \g, \w, etc.
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-04-02 [68dba97a4] Document psql's behavior of recalling the previously exe
-->
<para>
Fix <application>psql</> \p to always print what would be executed by \g or \w (Daniel
V&eacute;rit&eacute;)
</para>

<para>
Previously \p didn't properly print the reverted-to command after a
buffer contents reset.  CLARIFY?
</para>
</listitem>

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

      </itemizedlist>

    </sect4>

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

     <itemizedlist>

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-01-20 [cdc2a7047] Allow backslash line continuations in pgbench's meta com
-->
<para>
Allow pgbench's meta commands to span multiple lines via a
line-terminating backslash (Fabien Coelho)
</para>
</listitem>

     </itemizedlist>

    </sect4>

   </sect3>

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

    <itemizedlist>

<listitem>
<!--
Author: Magnus Hagander <magnus@hagander.net>
2017-01-17 [cada1af31] Add compression support to pg_receivexlog
-->
<para>
Add <link linkend="app-pgreceivewal"><application>pg_receivewal</></> option <option>-Z</>/<option>--compress</> to support compression (Michael
Paquier)
</para>
</listitem>

<listitem>
<!--
Author: Simon Riggs <simon@2ndQuadrant.com>
2017-01-04 [7c030783a] Add pg_recvlogical \-\-endpos=LSN
-->
<para>
Add <link linkend="app-pgrecvlogical"><application>pg_recvlogical</></> option (<option>--endpos</>) to specify the ending position
(Craig Ringer)
</para>

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

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

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

    </itemizedlist>

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

    <itemizedlist>

<listitem>
<!--
Author: Peter Eisentraut <peter_e@gmx.net>
2016-09-20 [46b55e7f8] pg_restore: Add -N option to exclude schemas
-->
<para>
Allow <application>pg_restore</> to exclude schemas (Michael Banck)
</para>

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

<listitem>
<!--
Author: Stephen Frost <sfrost@snowman.net>
2016-11-29 [4fafa579b] Add \-\-no-blobs option to pg_dump
-->
<para>
Add <option>--no-blobs</> option to
<application>pg_dump</> (Guillaume Lelarge)
</para>

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

<listitem>
<!--
Author: Simon Riggs <simon@2ndQuadrant.com>
2017-03-07 [9a83d56b3] Allow pg_dumpall to dump roles w/o user passwords
-->
<para>
Add <application>pg_dumpall</> option <option>--no-role-passwords</> to dump roles without user
passwords (Robins Tharakan, Simon Riggs)
</para>

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

<listitem>
<!--
Author: Andrew Dunstan <andrew@dunslane.net>
2017-03-22 [96a7128b7] Sync pg_dump and pg_dumpall output
-->
<para>
Issue fsync on the output files generated by <application>pg_dump</> and
<application>pg_dumpall</> (Michael Paquier)
</para>

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

    </itemizedlist>

   </sect4>
   
   <sect4>

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

    <itemizedlist>

<listitem>
<!--
Author: Magnus Hagander <magnus@hagander.net>
2016-10-23 [56c7d8d45] Allow pg_basebackup to stream transaction log in tar mod
Author: Fujii Masao <fujii@postgresql.org>
2016-12-21 [ecbdc4c55] Forbid invalid combination of options in pg_basebackup.
-->
<para>
Allow <application>pg_basebackup</> to stream transaction log in tar mode (Magnus
Hagander)
</para>

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

<listitem>
<!--
Author: Magnus Hagander <magnus@hagander.net>
2017-01-16 [e7b020f78] Make pg_basebackup use temporary replication slots
-->
<para>
Make <application>pg_basebackup</> use temporary replication slots (Magnus Hagander)
</para>

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

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

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

<listitem>
<!--
Author: Peter Eisentraut <peter_e@gmx.net>
2016-09-28 [6ad8ac602] Exclude additional directories in pg_basebackup
-->
<para>
Improve <application>pg_basebackup</>'s handling of which directories to skip (David
Steele)
</para>

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

    </itemizedlist>

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

    <itemizedlist>

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

<listitem>
<!--
Author: Peter Eisentraut <peter_e@gmx.net>
2016-10-19 [0be22457d] pg_ctl: Add long options for -w and -W
-->
<para>
Add log options for <application>pg_ctl</> wait (<option>--wait</>) and no-wait (<option>--no-wait</>) (Vik Fearing)
</para>
</listitem>

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

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

   </itemizedlist>
    
   </sect4>
   
   </sect3>

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

     <itemizedlist>

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

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-08-15 [ca9112a42] Stamp HEAD as 10devel.
-->
<para>
New major version numbering (Peter Eisentraut, Tom Lane)
</para>

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

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

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

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

<listitem>
<!--
Author: Andres Freund <andres@anarazel.de>
2017-02-27 [58b25e981] Add "Slab" MemoryContext implementation for efficient eq
-->
<para>
Add slab-like memory allocator for efficient fixed-size allocations
(Tomas Vondra)
</para>
</listitem>

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

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

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

<listitem>
<!--
Author: Andres Freund <andres@anarazel.de>
2017-03-10 [f8f1430ae] Enable 64 bit atomics on ARM64.
-->
<para>
Enable 64-bit atomic operations on <acronym>ARM64</> (Roman Shaposhnik)
</para>
</listitem>

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-01-02 [1d63f7d2d] Use clock_gettime(), if available, in instr_time measure
-->
<para>
Switch to using <function>clock_gettime()</>, if available, for duration measurements
(Tom Lane)
</para>

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

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

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

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

<listitem>
<!--
Author: Peter Eisentraut <peter_e@gmx.net>
2017-04-06 [510074f9f] Remove use of Jade and DSSSL
-->
<para>
Use <acronym>XSLT</> to build the Postgres documentation (Peter Eisentraut)
</para>

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

<listitem>
<!--
Author: Peter Eisentraut <peter_e@gmx.net>
2016-11-15 [e36ddab11] Build HTML documentation using XSLT stylesheets by defau
-->
<para>
Build <acronym>HTML</> documentation using <acronym>XSLT</> stylesheets by default (Peter
Eisentraut)
</para>
</listitem>

    </itemizedlist>

   </sect3>

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

    <itemizedlist>

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-09-29 [8e91e12bc] Allow contrib/file_fdw to read from a program, like COPY
-->
<para>
Allow <link linkend="file-fdw"><application>file_fdw</></> to read from program output as well as files (Corey Huinker, Adam Gomaa)
</para>
</listitem>

<listitem>
<!--
Author: Robert Haas <rhaas@postgresql.org>
2016-10-21 [7012b132d] postgres_fdw: Push down aggregates to remote servers.
-->
<para>
Push aggregates to foreign data wrapper servers, where possible (Jeevan
Chalke, Ashutosh Bapat)
</para>

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

<listitem>
<!--
Author: Heikki Linnakangas <heikki.linnakangas@iki.fi>
2016-08-26 [ae025a159] Support OID system column in postgres_fdw.
-->
<para>
Properly support <type>OID</> columns in <application>postgres_fdw</> tables (Etsuro Fujita)
</para>

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

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

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

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-11-29 [11da83a0e] Add uuid to the set of types supported by contrib/btree_
-->
<para>
Add indexing support to <application>btree_gist</> for the <type>UUID</> data type (Paul
Jungwirth)
</para>
</listitem>

<listitem>
<!--
Author: Andres Freund <andres@anarazel.de>
2017-03-09 [3717dc149] Add amcheck extension to contrib.
-->
<para>
Add <link linkend="amcheck"><application>amcheck</></> which can check the validity of btree indexes (Peter
Geoghegan)
</para>
</listitem>

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2017-03-27 [a6f22e835] Show ignored constants as "$N" rather than "?" in pg_sta
-->
<para>
Show ignored constants as <literal>$N</> rather than <literal>?</> in
<link linkend="pgstatstatements"><application>pg_stat_statements</></> (Lukas Fittl)
</para>
</listitem>

<listitem>
<!--
Author: Tom Lane <tgl@sss.pgh.pa.us>
2016-09-27 [f31a931fa] Improve contrib/cube's handling of zero-D cubes, infinit
-->
<para>
Improve <link linkend="cube"><application>cube</></>'s handling of zero-dimensional cubes (Tom Lane)
</para>

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

<listitem>
<!--
Author: Heikki Linnakangas <heikki.linnakangas@iki.fi>
2016-09-29 [6e654546f] Don't bother to lock bufmgr partitions in pg_buffercache
-->
<para>
Allow <link linkend="pgbuffercache"><application>pg_buffercache</></> to run without fewer locks (Ivan Kartyshov)
</para>

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

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

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

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

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

<listitem>
<!--
Author: Peter Eisentraut <peter_e@gmx.net>
2017-03-17 [fef2bcdcb] pageinspect: Add page_checksum function
-->
<para>
Add <function>page_checksum()</> function to <link linkend="pageinspect"><application>pageinspect</></> (Tomas Vondra)
</para>
</listitem>

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

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

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

     </itemizedlist>

   </sect3>

 </sect2>

 </sect1>
