<!-- doc/src/sgml/release-9.4.sgml -->
<!-- See header comment in release.sgml about typical markup -->
+ <sect1 id="release-9-4-4">
+ <title>Release 9.4.4</title>
+
+ <note>
+ <title>Release Date</title>
+ <simpara>2015-06-12</simpara>
+ </note>
+
+ <para>
+ This release contains a small number of fixes from 9.4.3.
+ For information about new features in the 9.4 major release, see
+ <xref linkend="release-9-4">.
+ </para>
+
+ <sect2>
+ <title>Migration to Version 9.4.4</title>
+
+ <para>
+ A dump/restore is not required for those running 9.4.X.
+ </para>
+
+ <para>
+ However, if you are upgrading an installation that was previously
+ upgraded using a <application>pg_upgrade</> version between 9.3.0 and
+ 9.3.4 inclusive, see the first changelog entry below.
+ </para>
+
+ <para>
+ Also, if you are upgrading from a version earlier than 9.4.2,
+ see <xref linkend="release-9-4-2">.
+ </para>
+ </sect2>
+
+ <sect2>
+ <title>Changes</title>
+
+ <itemizedlist>
+
+<!--
+Author: Robert Haas <rhaas@postgresql.org>
+Branch: master [068cfadf9] 2015-06-05 09:31:57 -0400
+Branch: REL9_4_STABLE [b6a3444fa] 2015-06-05 09:33:52 -0400
+Branch: REL9_3_STABLE [2a9b01928] 2015-06-05 09:34:15 -0400
+-->
+
+ <listitem>
+ <para>
+ Fix possible failure to recover from an inconsistent database state
+ (Robert Haas)
+ </para>
+
+ <para>
+ Recent <productname>PostgreSQL</> releases introduced mechanisms to
+ protect against multixact wraparound, but some of that code did not
+ account for the possibility that it would need to run during crash
+ recovery, when the database may not be in a consistent state. This
+ could result in failure to restart after a crash, or failure to start
+ up a secondary server. The lingering effects of a previously-fixed
+ bug in <application>pg_upgrade</> could also cause such a failure, in
+ installations that had used <application>pg_upgrade</> versions
+ between 9.3.0 and 9.3.4.
+ </para>
+
+ <para>
+ The <application>pg_upgrade</> bug in question was that it would
+ set <literal>oldestMultiXid</> to 1 in <filename>pg_control</> even
+ if the true value should be higher. With the fixes introduced in
+ this release, such a situation will result in immediate emergency
+ autovacuuming until a correct <literal>oldestMultiXid</> value can
+ be determined. Users can avoid that by doing manual
+ vacuuming <emphasis>before</> upgrading to this release.
+ In detail:
+
+ <orderedlist>
+ <listitem>
+ <para>
+ Check whether <application>pg_controldata</> reports <quote>Latest
+ checkpoint's oldestMultiXid</> to be 1. If not, there's nothing
+ to do.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Look in <filename>PGDATA/pg_multixact/offsets</> to see if there's a
+ file named <filename>0000</>. If there is, there's nothing to do.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Otherwise, for each table that has
+ <structname>pg_class</>.<structfield>relminmxid</> equal to 1,
+ <command>VACUUM</> that table with
+ both <xref linkend="guc-vacuum-multixact-freeze-min-age">
+ and <xref linkend="guc-vacuum-multixact-freeze-table-age"> set to
+ zero. (You can use the vacuum cost delay parameters described
+ in <xref linkend="runtime-config-resource-vacuum-cost"> to reduce
+ the performance consequences for concurrent sessions.) You must
+ use <productname>PostgreSQL</> 9.3.5 or later to perform this step.
+ </para>
+ </listitem>
+ </orderedlist>
+ </para>
+ </listitem>
+
+<!--
+Author: Tom Lane <tgl@sss.pgh.pa.us>
+Branch: master [f3b5565dd] 2015-06-07 15:32:09 -0400
+Branch: REL9_4_STABLE [be25a08a9] 2015-06-07 15:32:09 -0400
+Branch: REL9_3_STABLE [4f2458dd7] 2015-06-07 15:32:09 -0400
+Branch: REL9_2_STABLE [3e69a73b9] 2015-06-07 15:32:09 -0400
+Branch: REL9_1_STABLE [e06e56212] 2015-06-07 15:32:09 -0400
+Branch: REL9_0_STABLE [2fe1939b0] 2015-06-07 15:32:09 -0400
+-->
+
+ <listitem>
+ <para>
+ Fix rare failure to invalidate relation cache init file (Tom Lane)
+ </para>
+
+ <para>
+ With just the wrong timing of concurrent activity, a <command>VACUUM
+ FULL</> on a system catalog might fail to update the <quote>init file</>
+ that's used to avoid cache-loading work for new sessions. This would
+ result in later sessions being unable to access that catalog at all.
+ This is a very ancient bug, but it's so hard to trigger that no
+ reproducible case had been seen until recently.
+ </para>
+ </listitem>
+
+<!--
+Author: Tom Lane <tgl@sss.pgh.pa.us>
+Branch: master [ac23b711d] 2015-06-05 13:22:27 -0400
+Branch: REL9_4_STABLE [247263dc3] 2015-06-05 13:22:27 -0400
+Branch: REL9_3_STABLE [ac86eda63] 2015-06-05 13:22:27 -0400
+Branch: REL9_2_STABLE [04358dab2] 2015-06-05 13:22:27 -0400
+Branch: REL9_1_STABLE [002e7d144] 2015-06-05 13:22:27 -0400
+Branch: REL9_0_STABLE [dbd99c7f0] 2015-06-05 13:22:27 -0400
+-->
+
+ <listitem>
+ <para>
+ Avoid deadlock between incoming sessions and <literal>CREATE/DROP
+ DATABASE</> (Tom Lane)
+ </para>
+
+ <para>
+ A new session starting in a database that is the target of
+ a <command>DROP DATABASE</> command, or is the template for
+ a <command>CREATE DATABASE</> command, could cause the command to wait
+ for five seconds and then fail, even if the new session would have
+ exited before that.
+ </para>
+ </listitem>
+
+<!--
+Author: Tom Lane <tgl@sss.pgh.pa.us>
+Branch: master [3f59be836] 2015-06-03 11:59:10 -0400
+Branch: REL9_4_STABLE [f0a8515c4] 2015-06-03 11:58:47 -0400
+Branch: REL9_3_STABLE [d3fdec6ae] 2015-06-03 11:58:47 -0400
+-->
+
+ <listitem>
+ <para>
+ Improve planner's cost estimates for semi-joins and anti-joins with
+ inner indexscans (Tom Lane, Tomas Vondra)
+ </para>
+
+ <para>
+ This type of plan is quite cheap when all the join clauses are used
+ as index scan conditions, even if the inner scan would nominally
+ fetch many rows, because the executor will stop after obtaining one
+ row. The planner only partially accounted for that effect, and would
+ therefore overestimate the cost, leading it to possibly choose some
+ other much less efficient plan type.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </sect2>
+ </sect1>
+
<sect1 id="release-9-4-3">
<title>Release 9.4.3</title>
projects / postgresql / commitdiff