<sect1 id="release-8-3-18">

<title>Release 8.3.18</title>

<note>

<title>Release Date</title>

<simpara>2012-02-27</simpara>

</note>

<para>

This release contains a variety of fixes from 8.3.17.

For information about new features in the 8.3 major release, see

<xref linkend="release-8-3">.

</para>

<sect2>

<title>Migration to Version 8.3.18</title>

<para>

A dump/restore is not required for those running 8.3.X.

</para>

<para>

However, if you are upgrading from a version earlier than 8.3.17,

see the release notes for 8.3.17.

</para>

</sect2>

<sect2>

<title>Changes</title>

<itemizedlist>

<listitem>

<para>

Fix btree index corruption from insertions concurrent with vacuuming

(Tom Lane)

</para>

<para>

An index page split caused by an insertion could sometimes cause a

concurrently-running <command>VACUUM</> to miss removing index entries

that it should remove. After the corresponding table rows are removed,

the dangling index entries would cause errors (such as <quote>could not

read block N in file ...</>) or worse, silently wrong query results

after unrelated rows are re-inserted at the now-free table locations.

This bug has been present since release 8.2, but occurs so infrequently

that it was not diagnosed until now. If you have reason to suspect

that it has happened in your database, reindexing the affected index

will fix things.

</para>

</listitem>

<listitem>

<para>

Allow non-existent values for some settings in <command>ALTER

USER/DATABASE SET</> (Heikki Linnakangas)

</para>

<para>

Allow <varname>default_text_search_config</>,

<varname>default_tablespace</>, and <varname>temp_tablespaces</> to be

set to names that are not known. This is because they might be known

in another database where the setting is intended to be used, or for the

tablespace cases because the tablespace might not be created yet. The

same issue was previously recognized for <varname>search_path</>, and

these settings now act like that one.

</para>

</listitem>

<listitem>

<para>

Track the OID counter correctly during WAL replay, even when it wraps

around (Tom Lane)

</para>

<para>

Previously the OID counter would remain stuck at a high value until the

system exited replay mode. The practical consequences of that are

usually nil, but there are scenarios wherein a standby server that's

been promoted to master might take a long time to advance the OID

counter to a reasonable value once values are needed.

</para>

</listitem>

<listitem>

<para>

Fix regular expression back-references with <literal>*</> attached

(Tom Lane)

</para>

<para>

Rather than enforcing an exact string match, the code would effectively

accept any string that satisfies the pattern sub-expression referenced

by the back-reference symbol.

</para>

<para>

A similar problem still afflicts back-references that are embedded in a

larger quantified expression, rather than being the immediate subject

of the quantifier. This will be addressed in a future

<productname>PostgreSQL</> release.

</para>

</listitem>

<listitem>

<para>

Fix recently-introduced memory leak in processing of

<type>inet</>/<type>cidr</> values (Heikki Linnakangas)

</para>

<para>

A patch in the December 2011 releases of <productname>PostgreSQL</>

caused memory leakage in these operations, which could be significant

in scenarios such as building a btree index on such a column.

</para>

</listitem>

<listitem>

<para>

Avoid double close of file handle in syslogger on Windows (MauMau)

</para>

<para>

Ordinarily this error was invisible, but it would cause an exception

when running on a debug version of Windows.

</para>

</listitem>

<listitem>

<para>

Fix I/O-conversion-related memory leaks in plpgsql

(Andres Freund, Jan Urbanski, Tom Lane)

</para>

<para>

Certain operations would leak memory until the end of the current

function.

</para>

</listitem>

<listitem>

<para>

Improve <application>pg_dump</>'s handling of inherited table columns

(Tom Lane)

</para>

<para>

<application>pg_dump</> mishandled situations where a child column has

a different default expression than its parent column. If the default

is textually identical to the parent's default, but not actually the

same (for instance, because of schema search path differences) it would

not be recognized as different, so that after dump and restore the

child would be allowed to inherit the parent's default. Child columns

that are <literal>NOT NULL</> where their parent is not could also be

restored subtly incorrectly.

</para>

</listitem>

<listitem>

<para>

Fix <application>pg_restore</>'s direct-to-database mode for

INSERT-style table data (Tom Lane)

</para>

<para>

Direct-to-database restores from archive files made with

<option>--inserts</> or <option>--column-inserts</> options fail when

using <application>pg_restore</> from a release dated September or

December 2011, as a result of an oversight in a fix for another

problem. The archive file itself is not at fault, and text-mode

output is okay.

</para>

</listitem>

<listitem>

<para>

Fix error in <filename>contrib/intarray</>'s <literal>int[] &amp;

int[]</> operator (Guillaume Lelarge)

</para>

<para>

If the smallest integer the two input arrays have in common is 1,

and there are smaller values in either array, then 1 would be

incorrectly omitted from the result.

</para>

</listitem>

<listitem>

<para>

Fix error detection in <filename>contrib/pgcrypto</>'s

<function>encrypt_iv()</> and <function>decrypt_iv()</>

(Marko Kreen)

</para>

<para>

These functions failed to report certain types of invalid-input errors,

and would instead return random garbage values for incorrect input.

</para>

</listitem>

<listitem>

<para>

Fix one-byte buffer overrun in <filename>contrib/test_parser</>

(Paul Guyot)

</para>

<para>

The code would try to read one more byte than it should, which would

crash in corner cases.

Since <filename>contrib/test_parser</> is only example code, this is

not a security issue in itself, but bad example code is still bad.

</para>

</listitem>

<listitem>

<para>

Use <function>__sync_lock_test_and_set()</> for spinlocks on ARM, if

available (Martin Pitt)

</para>

<para>

This function replaces our previous use of the <literal>SWPB</>

instruction, which is deprecated and not available on ARMv6 and later.

Reports suggest that the old code doesn't fail in an obvious way on

recent ARM boards, but simply doesn't interlock concurrent accesses,

leading to bizarre failures in multiprocess operation.

</para>

</listitem>

<listitem>

<para>

Use <option>-fexcess-precision=standard</> option when building with

gcc versions that accept it (Andrew Dunstan)

</para>

<para>

This prevents assorted scenarios wherein recent versions of gcc will

produce creative results.

</para>

</listitem>

<listitem>

<para>

Allow use of threaded Python on FreeBSD (Chris Rees)

</para>

<para>

Our configure script previously believed that this combination wouldn't

work; but FreeBSD fixed the problem, so remove that error check.

</para>

</listitem>

</itemizedlist>

</sect2>

</sect1>