<sect1 id="release-8-4-19">

<title>Release 8.4.19</title>

<note>

<title>Release Date</title>

<simpara>2013-12-05</simpara>

</note>

<para>

This release contains a variety of fixes from 8.4.18.

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

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

</para>

<sect2>

<title>Migration to Version 8.4.19</title>

<para>

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

</para>

<para>

However, this release corrects a potential data corruption

issue. See the first changelog entry below to find out whether

your installation has been affected and what steps you can take if so.

</para>

<para>

Also, if you are upgrading from a version earlier than 8.4.17,

see the release notes for 8.4.17.

</para>

</sect2>

<sect2>

<title>Changes</title>

<itemizedlist>

<listitem>

<para>

Fix <command>VACUUM</>'s tests to see whether it can

update <structfield>relfrozenxid</> (Andres Freund)

</para>

<para>

In some cases <command>VACUUM</> (either manual or autovacuum) could

incorrectly advance a table's <structfield>relfrozenxid</> value,

allowing tuples to escape freezing, causing those rows to become

invisible once 2^31 transactions have elapsed. The probability of

data loss is fairly low since multiple incorrect advancements would

need to happen before actual loss occurs, but it's not zero. Users

upgrading from release 8.4.8 or earlier are not affected, but all later

versions contain the bug.

</para>

<para>

The issue can be ameliorated by, after upgrading, vacuuming all tables

in all databases while having <link

linkend="guc-vacuum-freeze-table-age"><varname>vacuum_freeze_table_age</></link>

set to zero. This will fix any latent corruption but will not be able

to fix all pre-existing data errors. However, an installation can be

presumed safe after performing this vacuuming if it has executed fewer

than 2^31 update transactions in its lifetime (check this with

<literal>SELECT txid_current() < 2^31</>).

</para>

</listitem>

<listitem>

<para>

Fix race condition in GIN index posting tree page deletion (Heikki

Linnakangas)

</para>

<para>

This could lead to transient wrong answers or query failures.

</para>

</listitem>

<listitem>

<para>

Avoid flattening a subquery whose <literal>SELECT</> list contains a

volatile function wrapped inside a sub-<literal>SELECT</> (Tom Lane)

</para>

<para>

This avoids unexpected results due to extra evaluations of the

volatile function.

</para>

</listitem>

<listitem>

<para>

Fix planner's processing of non-simple-variable subquery outputs

nested within outer joins (Tom Lane)

</para>

<para>

This error could lead to incorrect plans for queries involving

multiple levels of subqueries within <literal>JOIN</> syntax.

</para>

</listitem>

<listitem>

<para>

Fix premature deletion of temporary files (Andres Freund)

</para>

</listitem>

<listitem>

<para>

Fix possible read past end of memory in rule printing (Peter Eisentraut)

</para>

</listitem>

<listitem>

<para>

Fix array slicing of <type>int2vector</> and <type>oidvector</> values

(Tom Lane)

</para>

<para>

Expressions of this kind are now implicitly promoted to

regular <type>int2</> or <type>oid</> arrays.

</para>

</listitem>

<listitem>

<para>

Fix incorrect behaviors when using a SQL-standard, simple GMT offset

timezone (Tom Lane)

</para>

<para>

In some cases, the system would use the simple GMT offset value when

it should have used the regular timezone setting that had prevailed

before the simple offset was selected. This change also causes

the <function>timeofday</> function to honor the simple GMT offset

zone.

</para>

</listitem>

<listitem>

<para>

Prevent possible misbehavior when logging translations of Windows

error codes (Tom Lane)

</para>

</listitem>

<listitem>

<para>

Properly quote generated command lines in <application>pg_ctl</>

(Naoya Anzai and Tom Lane)

</para>

<para>

This fix applies only to Windows.

</para>

</listitem>

<listitem>

<para>

Fix <application>pg_dumpall</> to work when a source database

sets <link

linkend="guc-default-transaction-read-only"><varname>default_transaction_read_only</></link>

via <command>ALTER DATABASE SET</> (Kevin Grittner)

</para>

<para>

Previously, the generated script would fail during restore.

</para>

</listitem>

<listitem>

<para>

Fix <application>ecpg</>'s processing of lists of variables

declared <type>varchar</> (Zolt&aacute;n B&ouml;sz&ouml;rm&eacute;nyi)

</para>

</listitem>

<listitem>

<para>

Make <filename>contrib/lo</> defend against incorrect trigger definitions

(Marc Cousin)

</para>

</listitem>

<listitem>

<para>

Update time zone data files to <application>tzdata</> release 2013h

for DST law changes in Argentina, Brazil, Jordan, Libya,

Liechtenstein, Morocco, and Palestine. Also, new timezone

abbreviations WIB, WIT, WITA for Indonesia.

</para>

</listitem>

</itemizedlist>

</sect2>

</sect1>