<note>

<title>Release Date</title>

<simpara>2011-??-??</simpara>

<simpara>2011-09-12</simpara>

</note>

<para>CURRENT AS OF 2011-08-17</para>

<sect2>

<title>Overview</title>

<listitem>

<para>

Allow data-modification commands

(<command>INSERT</>/<command>UPDATE</>/<command>DELETE)</> in

(<command>INSERT</>/<command>UPDATE</>/<command>DELETE</>) in

<link linkend="queries-with"><literal>WITH</></link> clauses

</para>

</listitem>

<listitem>

<para>

Require superuser or <literal>CREATEROLE</> permissions in order to

setrolecomments (Tom Lane)

set comments on roles (Tom Lane)

</para>

</listitem>

</para>

<para>

Previously<function>pg_last_xlog_receive_location()</> could

move backward when streaming replication is restarted.

Previously, the value of<function>pg_last_xlog_receive_location()</>

couldmove backward when streaming replication is restarted.

</para>

</listitem>

</para>

<para>

Previously replication connections were always logged.

Previously, replication connections were always logged.

</para>

</listitem>

</para>

<para>

This fixes scenarioswherebackends might holdopenfilesthat

were long since deleted, preventing the kernel from reclaiming

This fixes scenariosin whichbackends might hold filesopen long

after they were deleted, preventing the kernel from reclaiming

disk space.

</para>

</listitem>

</para>

<para>

New detailsshow <acronym>WAL</> file and sync activity.

New detailsinclude <acronym>WAL</> file and sync activity.

</para>

</listitem>

<listitem>

<para>

Allow auto-tuning of <link

Provide auto-tuning of <link

linkend="guc-wal-buffers"><varname>wal_buffers</></link> (Greg

Smith)

</para>

<para>

<varname>wal_buffers</> is nowauto-tuned by default based on

thesize of <varname>shared_buffers</>.

By default, the value of<varname>wal_buffers</> is nowchosen

automatically based onthevalue of <varname>shared_buffers</>.

</para>

</listitem>

</para>

<para>

This allows the primary to wait for a standby to writethe transaction

information to disk before acknowledging the commit.

This allows the primaryserverto wait for a standby to writea

transaction'sinformation to disk before acknowledging the commit.

One standby at a time can take the role of the synchronous standby,

as controlled by the

<link linkend="guc-synchronous-standby-names"><varname>synchronous_standby_names</varname></link>

<listitem>

<para>

Add protocol support for sending file system backups tostandbys using

the streaming replication network connection (Magnus Hagander,

Add protocol support for sending file system backups tostandby servers

usingthe streaming replication network connection (Magnus Hagander,

Heikki Linnakangas)

</para>

<listitem>

<para>

Addreplication <link linkend="SQL-CREATEROLE">permission</link>

Adda <link linkend="SQL-CREATEROLE">replicationpermission</link>

for roles (Magnus Hagander)

</para>

<para>

Increase the maximum values for

<link linkend="guc-max-standby-archive-delay"><varname>max_standby_archive_delay</varname></link> and

<link linkend="guc-max-standby-streaming-delay"><varname>max_standby_streaming_delay</varname></link>.

<link linkend="guc-max-standby-streaming-delay"><varname>max_standby_streaming_delay</varname></link>

</para>

<para>

Previously, asking for serializable isolation guaranteed only that a

single MVCC snapshot would be used for the entire transaction, which

allowed certain documented anomalies. The old snapshot isolation

behavior is stillaccessible by requesting the <link

behavior is stillavailable by requesting the <link

linkend="xact-repeatable-read"><literal>REPEATABLE READ</></link>

isolation level.

</para>

<listitem>

<para>

Allow data-modification commands

(<command>INSERT</>/<command>UPDATE</>/<command>DELETE)</> in

(<command>INSERT</>/<command>UPDATE</>/<command>DELETE</>) in

<link linkend="queries-with"><literal>WITH</></link> clauses

(Marko Tiikkaja, Hitoshi Harada)

</para>

</para>

<para>

Some other database system already allowed this behavior, and

The SQL standard allows this behavior, and

because of the primary key, the result is unambiguous.

</para>

</listitem>

</para>

<para>

Previously <command>EXPLAIN ANALYZE</> usedaslightly different

snapshot for queries involving rules. The <command>EXPLAIN ANALYZE</>

behavior was judged to be more logical.

Previously <command>EXPLAIN ANALYZE</> used slightly different

snapshottimingfor queries involving rules. The

<command>EXPLAIN ANALYZE</>behavior was judged to be more logical.

</para>

</listitem>

</para>

<para>

Previously collation could only be set at database creation.

Previously collation (the sort ordering of text strings) could only be

chosen at database creation.

Collation can now be set per column, domain, index, or

expression, via the SQL-standard <literal>COLLATE</> clause.

</para>

</para>

<para>

The new option is called <literal>NOT VALID</>, which can

later be modified to <literal>VALIDATED</> and validation

The new option is called <literal>NOT VALID</>. The constraint's

state canlater be modified to <literal>VALIDATED</> and validation

checks performed. Together these allow you to add a foreign key

with minimal impact on read and write operations.

</para>

<listitem>

<para>

Fix possible <quote>tuple concurrently updated</quote> error

when two backendsattempted to add an inheritance

when two backendsattempt to add an inheritance

child to the same table at the same time (Robert Haas)

</para>

<para>

<link linkend="sql-altertable"><command>ALTER TABLE</command></link>

now takes a stronger lock on the parent table, so thatboth children do

not try to update it simultaneously.

now takes a stronger lock on the parent table, so thatthe sessions

cannot try to update it simultaneously.

</para>

</listitem>

</para>

<para>

This is similar to the existing session-level advisory locks,

butthe locks are automatically released at transaction end.

These are similar to the existing session-level advisory locks,

butsuch locks are automatically released at transaction end.

</para>

</listitem>

<para>

Previously all <type>numeric</> values had four-byte headers;

this saves on disk storage.

thischangesaves on disk storage.

</para>

</listitem>

<listitem>

<para>

Add support for casting from <type>int4</> and <type>int8</>

to <type>numeric</> (Joey Adams)

to <type>money</> (Joey Adams)

</para>

</listitem>

<listitem>

<para>

Add SQL function <link

linkend="format"><function>format(text)</></link>, which

behaveslikeC's <function>printf()</> (Pavel Stehule, Robert

Haas)

linkend="format"><function>format(text, ...)</></link>, which

behavesanalogously toC's <function>printf()</> (Pavel Stehule,

RobertHaas)

</para>

<para>

</para>

<para>

The functions are <link

These functions are <link

linkend="plpython-util"><literal>plpy.quote_ident</></link>,

<link linkend="plpython-util"><literal>plpy.quote_literal</></link>,

and <link

<listitem>

<para>

Modify <filename>contrib</> modules andstored procedure

Modify <filename>contrib</> modules andprocedural

languages to install via the new <link

linkend="extend-extensions">extension</link> mechanism (Tom Lane,

Dimitri Fontaine)