Major enhancements in <productname>PostgreSQL</> 9.6 include:

</para>

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<itemizedlist>

<listitem>

<para>

To be filled in, but see below for the long version

Parallel sequential scans, joins and aggregates

</para>

</listitem>

<listitem>

<para>

Elimination of repetitive scanning of old data by autovacuum

</para>

</listitem>

<listitem>

<para>

Synchronous replication now allows multiple standby servers for

increased reliability

</para>

</listitem>

<listitem>

<para>

Full-text search for phrases

</para>

</listitem>

<listitem>

<para>

Support for remote joins, sorts, and updates

in <filename>postgres_fdw</>

</para>

</listitem>

<listitem>

<para>

Substantial performance improvements, especially in the area of

improving scalability on many-CPU servers

</para>

</listitem>

2016-04-24 [8f91d87d4] Fix documentation & config inconsistencies around 428b1d

2016-04-26 [72a98a639] Don't open formally non-existent segments in _mdfd_getse

2016-05-04 [a71248708] Fix transient mdsync() errors of truncated relations due

2016-02-16 [7975c5e0a] Allow the WAL writer to flush WAL at a reduced rate.

-->

<para>

Where feasible, trigger kernel writeback after a configurable number

<listitem>

<!--

2016-02-16 [7975c5e0a] Allow the WAL writer to flush WAL at a reduced rate.

-->

<para>

Reduce the WAL writer's flush rate to reduce storage bottlenecks

(Andres Freund)

</para>

</listitem>

<listitem>

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2016-04-08 [719c84c1b] Extend relations multiple blocks at a time to improve sc

-->

<para>

</para>

<para>

This reduces kernel traffic and improves scalability when multiple

processes are inserting into the same relation.

This improves scalability by decreasing contention.

</para>

</listitem>

<listitem>

<!--

2016-04-08 [071180377] Use quicksort, not replacement selection, for external s

2016-03-17 [0011c0091] Improve memory management for external sorts.

-->

<para>

Improve sorting performance by using quicksort, not replacement

selection, within steps of an external sort (Peter Geoghegan)

</para>

<para>

This behavior can be adjusted via the new configuration

parameter <xref linkend="guc-replacement-sort-tuples">.

</para>

</listitem>

<listitem>

<!--

2016-03-17 [0011c0091] Improve memory management for external sorts.

-->

<para>

Improve memory management for external sorts (Peter Geoghegan)

The new approach makes better use of CPU cache for typical cache

sizes and data volumes. Where necessary, the behavior can be

adjusted via the new configuration

parameter <xref linkend="guc-replacement-sort-tuples">,

which see for further details.

</para>

</listitem>

<listitem>

<!--

2015-11-06 [a76ef15d9] Add sort support routine for the UUID data type.

2016-02-03 [b47b4dbf6] Extend sortsupport for text to more opclasses.

2016-02-17 [f1f5ec1ef] Reuse abbreviated keys in ordered [set] aggregates.

-->

<para>

Speed up sorting of <type>uuid</>-type columns (Peter Geoghegan)

Speed up sorting of <type>uuid</>, <type>bytea</>,

and <type>char(n)</> fields by using <quote>abbreviated</> keys

(Peter Geoghegan)

</para>

</listitem>

<listitem>

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2015-12-16 [b648b7034] Speed up CREATE INDEX CONCURRENTLY's TID sort.

-->

<para>

Speed up <command>CREATE INDEX CONCURRENTLY</> by treating TIDs

as 64-bit integers during the sort phase (Peter Geoghegan)

Support for abbreviated keys has also been added to the non-default

operator classes <literal>text_pattern_ops</>,

<literal>varchar_pattern_ops</>, and <literal>bpchar_pattern_ops</>.

Processing of ordered-set aggregates can also now exploit

abbreviated keys.

</para>

</listitem>

<listitem>

<!--

2016-02-17 [f1f5ec1ef] Reuse abbreviated keys in ordered [set] aggregates.

2015-12-16 [b648b7034] Speed up CREATE INDEX CONCURRENTLY's TID sort.

-->

<para>

Improve performance of ordered-set aggregates byreusing

abbreviated-key information (Peter Geoghegan)

Speed up <command>CREATE INDEX CONCURRENTLY</> bytreating TIDs

as 64-bit integers during the sort phase (Peter Geoghegan)

</para>

</listitem>

<listitem>

<!--

2016-04-06 [989be0810] Support multiple synchronous standby servers.

2016-04-27 [4c804fbdf] Clean up parsing of synchronous_standby_names GUC variab

2016-04-30 [17d5db352] Remove warning about num_sync being too large in synchro

-->

<para>

Support synchronous replication with multiple synchronous standby

servers, not just one (Masahiko Sawada, Beena Emerson, Michael

Paquier, Fujii Masao, Kyotaro Horiguchi)

</para>

<para>

The number of standby servers that must acknowledge a commit before

it's considered done is now configurable.

</para>

</listitem>

<listitem>

<!--

2016-03-29 [314cbfc5d] Add new replication mode synchronous_commit = 'remote_ap

-->

<para>

Add new setting <literal>remote_apply</> for configuration parameter

<xref linkend="guc-synchronous-commit"> (Thomas Munro)

</para>

<para>

In this mode, the master waits for the transaction to be applied on

the standby server, not just written to disk. That means that you

can count on a transaction started on the standby to see all commits

previously acknowledged by the master.

</para>

</listitem>

<listitem>

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2015-08-11 [6fcd88511] Allow pg_create_physical_replication_slot() to reserve W

2015-09-06 [c314ead5b] Add ability to reserve WAL upon slot creation via replic

-->

</para>

</listitem>

<listitem>

<!--

2016-04-06 [989be0810] Support multiple synchronous standby servers.

2016-04-27 [4c804fbdf] Clean up parsing of synchronous_standby_names GUC variab

2016-04-30 [17d5db352] Remove warning about num_sync being too large in synchro

-->

<para>

Support synchronous replication with multiple synchronous standby

servers, not just one (Sawada Masahiko, Beena Emerson, Michael

Paquier, Fujii Masao, Kyotaro Horiguchi)

</para>

</listitem>

<listitem>

<!--

2016-03-29 [314cbfc5d] Add new replication mode synchronous_commit = 'remote_ap

-->

<para>

Add new setting <literal>remote_apply</> for configuration parameter

<xref linkend="guc-synchronous-commit"> (Thomas Munro)

</para>

<para>

In this mode, the master waits for the transaction to be applied on

the standby server, not just written to disk. That means that you

can count on a transaction started on the standby to see all commits

previously acknowledged by the master.

</para>

</listitem>

</itemizedlist>

</sect3>

<para>

Add options to <command>ALTER OPERATOR</command> to change the

selectivity functions associated with an existing operator

(Uriy Zhuravlev)

(Yury Zhuravlev)

</para>

</listitem>

<para>

Allow omitting one or both boundaries in an array slice specifier,

for example <literal>array_col[3:]</>

(YUriy Zhuravlev)

(Yury Zhuravlev)

</para>

<para>

2016-04-07 [bb140506d] Phrase full text search.

-->

<para>

Improve fulltext search to support searching for phrases, that is,

Improve full-text search to support searching for phrases, that is,

lexemes appearing adjacent to each other in a specific order, or with

at most a specified distance between them

(Teodor Sigaev, Oleg Bartunov, Dmitry Ivanov)

</para>

<para>

These are <function>delete()</>, <function>filter()</>,

These are <function>ts_delete()</>, <function>ts_filter()</>,

<function>unnest()</>, <function>tsvector_to_array()</>,

<function>array_to_tsvector()</>, and a variant

of <function>setweight()</> that sets the weight only for specified

-->

<para>

Add <function>pg_size_bytes()</> function to convert human-readable

size strings to numbers (Pavel Stehule, Vitaly Burovoy)

size strings to numbers (Pavel Stehule, Vitaly Burovoy, Dean Rasheed)

</para>

<para>

2016-05-05 [7a622b273] Rename pgbench min/max to least/greatest, and fix handli

-->

<para>

Support some <link linkend="pgbench-builtin-functions">built-in

functions</> in expressions in backslash commands (Fabien Coelho)

Support floating-point arithmetic, as well as

some <link linkend="pgbench-builtin-functions">built-in functions</>,

in expressions in backslash commands (Fabien Coelho)

</para>

</listitem>

<listitem>

<!--

2016-02-03 [b47b4dbf6] Extend sortsupport for text to more opclasses.

-->

<para>

Generalize the SortSupport for <type>text</> so that it can be

used by other types such as <type>bpchar</> (Peter Geoghegan)

</para>

</listitem>

<listitem>

<!--

2016-02-04 [c1772ad92] Change the way that LWLocks for extensions are allocated

-->

<para>

-->

<para>

Add selectivity estimation functions for <filename>contrib/intarray</>

operators, to improve plans for queries using those operators (Uriy

operators, to improve plans for queries using those operators (Yury

Zhuravlev, Alexander Korotkov)

</para>

</listitem>

<listitem>

<!--

2016-01-28 [96198d94c] Avoid multiple foreign server connections when all use s

-->

<para>

Use a single foreign-server connection for local user IDs that all

map to the same remote user (Ashutosh Bapat)

</para>

</listitem>

<listitem>

<!--

2016-02-03 [dc203dc3a] postgres_fdw: Allow fetch_size to be set per-table or pe

-->

<para>

Allow the fetch size to be set as a server or table option

(Corey Huinker)

</para>

<para>

Formerly, <filename>postgres_fdw</> always fetched 100 rows at a time

from remote queries; now that behavior is adjustable.

</para>

</listitem>

<listitem>

<!--

2015-11-03 [f18c944b6] postgres_fdw: Add ORDER BY to some remote SQL queries.

2015-12-22 [ccd8f9792] postgres_fdw: Consider requesting sorted data so we can

-->

<listitem>

<!--

2016-02-03 [dc203dc3a] postgres_fdw: Allow fetch_size to be set per-table or pe

-->

<para>

Allow the fetch size to be set as a server or table option

(Corey Huinker)

</para>

<para>

Formerly, <filename>postgres_fdw</> always fetched 100 rows at a time

from remote queries; now that behavior is adjustable.

</para>

</listitem>

<listitem>

<!--

2016-01-28 [96198d94c] Avoid multiple foreign server connections when all use s

-->

<para>

Use a single foreign-server connection for local user IDs that all

map to the same remote user (Ashutosh Bapat)

</para>

</listitem>

<listitem>

<!--

2016-04-21 [f039eaac7] Allow queries submitted by postgres_fdw to be canceled.

-->

<para>