<sect1 id="release-8-4-21">

<title>Release 8.4.21</title>

<note>

<title>Release Date</title>

<simpara>2014-03-20</simpara>

</note>

<para>

This release contains a variety of fixes from 8.4.20.

For information about new features in the 8.4 major release, see

<xref linkend="release-8-4">.

</para>

<para>

The <productname>PostgreSQL</> community will stop releasing updates

for the 8.4.X release series in July 2014.

Users are encouraged to update to a newer release branch soon.

</para>

<sect2>

<title>Migration to Version 8.4.21</title>

<para>

A dump/restore is not required for those running 8.4.X.

</para>

<para>

However, if you are upgrading from a version earlier than 8.4.19,

see <xref linkend="release-8-4-19">.

</para>

</sect2>

<sect2>

<title>Changes</title>

<itemizedlist>

<listitem>

<para>

Restore GIN metapages unconditionally to avoid torn-page risk

(Heikki Linnakangas)

</para>

<para>

Although this oversight could theoretically result in a corrupted

index, it is unlikely to have caused any problems in practice, since

the active part of a GIN metapage is smaller than a standard 512-byte

disk sector.

</para>

</listitem>

<listitem>

<para>

Allow regular-expression operators to be terminated early by query

cancel requests (Tom Lane)

</para>

<para>

This prevents scenarios wherein a pathological regular expression

could lock up a server process uninterruptably for a long time.

</para>

</listitem>

<listitem>

<para>

Remove incorrect code that tried to allow <literal>OVERLAPS</> with

single-element row arguments (Joshua Yanovski)

</para>

<para>

This code never worked correctly, and since the case is neither

specified by the SQL standard nor documented, it seemed better to

remove it than fix it.

</para>

</listitem>

<listitem>

<para>

Avoid getting more than <literal>AccessShareLock</> when de-parsing a

rule or view (Dean Rasheed)

</para>

<para>

This oversight resulted in <application>pg_dump</> unexpectedly

acquiring <literal>RowExclusiveLock</> locks on tables mentioned as

the targets of <literal>INSERT</>/<literal>UPDATE</>/<literal>DELETE</>

commands in rules. While usually harmless, that could interfere with

concurrent transactions that tried to acquire, for example,

<literal>ShareLock</> on those tables.

</para>

</listitem>

<listitem>

<para>

Prevent interrupts while reporting non-<literal>ERROR</> messages

(Tom Lane)

</para>

<para>

This guards against rare server-process freezeups due to recursive

entry to <function>syslog()</>, and perhaps other related problems.

</para>

</listitem>

<listitem>

<para>

Update time zone data files to <application>tzdata</> release 2014a

for DST law changes in Fiji and Turkey, plus historical changes in

Israel and Ukraine.

</para>

<para>

</para>

</listitem>

</itemizedlist>

</sect2>

</sect1>