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<sect1 id="release-9-2-21">

<title>Release 9.2.21</title>

<note>

<title>Release Date</title>

<simpara>2017-05-11</simpara>

</note>

<para>

This release contains a variety of fixes from 9.2.20.

For information about new features in the 9.2 major release, see

<xref linkend="release-9-2">.

</para>

<para>

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

for the 9.2.X release series in September 2017.

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

</para>

<sect2>

<title>Migration to Version 9.2.21</title>

<para>

A dump/restore is not required for those running 9.2.X.

</para>

<para>

However, if you are upgrading from a version earlier than 9.2.20,

see <xref linkend="release-9-2-20">.

</para>

</sect2>

<sect2>

<title>Changes</title>

<itemizedlist>

<listitem>

<para>

Fix possible corruption of <quote>init forks</> of unlogged indexes

(Robert Haas, Michael Paquier)

</para>

<para>

This could result in an unlogged index being set to an invalid state

after a crash and restart. Such a problem would persist until the

index was dropped and rebuilt.

</para>

</listitem>

<listitem>

<para>

Fix incorrect reconstruction of <structname>pg_subtrans</> entries

when a standby server replays a prepared but uncommitted two-phase

transaction (Tom Lane)

</para>

<para>

In most cases this turned out to have no visible ill effects, but in

corner cases it could result in circular references

in <structname>pg_subtrans</>, potentially causing infinite loops

in queries that examine rows modified by the two-phase transaction.

</para>

</listitem>

<listitem>

<para>

Ensure parsing of queries in extension scripts sees the results of

immediately-preceding DDL (Julien Rouhaud, Tom Lane)

</para>

<para>

Due to lack of a cache flush step between commands in an extension

script file, non-utility queries might not see the effects of an

immediately preceding catalog change, such as <command>ALTER TABLE

... RENAME</>.

</para>

</listitem>

<listitem>

<para>

Skip tablespace privilege checks when <command>ALTER TABLE ... ALTER

COLUMN TYPE</> rebuilds an existing index (Noah Misch)

</para>

<para>

The command failed if the calling user did not currently have

<literal>CREATE</> privilege for the tablespace containing the index.

That behavior seems unhelpful, so skip the check, allowing the

index to be rebuilt where it is.

</para>

</listitem>

<listitem>

<para>

Fix <command>ALTER TABLE ... VALIDATE CONSTRAINT</> to not recurse

to child tables when the constraint is marked <literal>NO INHERIT</>

(Amit Langote)

</para>

<para>

This fix prevents unwanted <quote>constraint does not exist</> failures

when no matching constraint is present in the child tables.

</para>

</listitem>

<listitem>

<para>

Fix <command>VACUUM</> to account properly for pages that could not

be scanned due to conflicting page pins (Andrew Gierth)

</para>

<para>

This tended to lead to underestimation of the number of tuples in

the table. In the worst case of a small heavily-contended

table, <command>VACUUM</> could incorrectly report that the table

contained no tuples, leading to very bad planning choices.

</para>

</listitem>

<listitem>

<para>

Ensure that bulk-tuple-transfer loops within a hash join are

interruptible by query cancel requests (Tom Lane, Thomas Munro)

</para>

</listitem>

<listitem>

<para>

Fix <function>cursor_to_xml()</> to produce valid output

with <replaceable>tableforest</> = false

(Thomas Munro, Peter Eisentraut)

</para>

<para>

Previously it failed to produce a wrapping <literal>&lt;table&gt;</>

element.

</para>

</listitem>

<listitem>

<para>

Improve performance of <structname>pg_timezone_names</> view

(Tom Lane, David Rowley)

</para>

</listitem>

<listitem>

<para>

Fix sloppy handling of corner-case errors from <function>lseek()</>

and <function>close()</> (Tom Lane)

</para>

<para>

Neither of these system calls are likely to fail in typical situations,

but if they did, <filename>fd.c</> could get quite confused.

</para>

</listitem>

<listitem>

<para>

Fix incorrect check for whether postmaster is running as a Windows

service (Michael Paquier)

</para>

<para>

This could result in attempting to write to the event log when that

isn't accessible, so that no logging happens at all.

</para>

</listitem>

<listitem>

<para>

Fix <application>ecpg</> to support <command>COMMIT PREPARED</>

and <command>ROLLBACK PREPARED</> (Masahiko Sawada)

</para>

</listitem>

<listitem>

<para>

Fix a double-free error when processing dollar-quoted string literals

in <application>ecpg</> (Michael Meskes)

</para>

</listitem>

<listitem>

<para>

In <application>pg_dump</>, fix incorrect schema and owner marking for

comments and security labels of some types of database objects

(Giuseppe Broccolo, Tom Lane)

</para>

<para>

In simple cases this caused no ill effects; but for example, a

schema-selective restore might omit comments it should include, because

they were not marked as belonging to the schema of their associated

object.

</para>

</listitem>

<listitem>

<para>

Avoid emitting an invalid list file in <literal>pg_restore -l</>

when SQL object names contain newlines (Tom Lane)

</para>

<para>

Replace newlines by spaces, which is sufficient to make the output

valid for <literal>pg_restore -L</>'s purposes.

</para>

</listitem>

<listitem>

<para>

Fix <application>pg_upgrade</> to transfer comments and security labels

attached to <quote>large objects</> (blobs) (Stephen Frost)

</para>

<para>

Previously, blobs were correctly transferred to the new database, but

any comments or security labels attached to them were lost.

</para>

</listitem>

<listitem>

<para>

Improve error handling

in <filename>contrib/adminpack</>'s <function>pg_file_write()</>

function (Noah Misch)

</para>

<para>

Notably, it failed to detect errors reported

by <function>fclose()</>.

</para>

</listitem>

<listitem>

<para>

In <filename>contrib/dblink</>, avoid leaking the previous unnamed

connection when establishing a new unnamed connection (Joe Conway)

</para>

</listitem>

<listitem>

<para>

Support OpenSSL 1.1.0 (Heikki Linnakangas, Andreas Karlsson, Tom Lane)

</para>

<para>

This is a back-patch of work previously done in newer branches;

it's needed since many platforms are adopting newer OpenSSL versions.

</para>

</listitem>

<listitem>

<para>

Support Tcl 8.6 in MSVC builds (&Aacute;lvaro Herrera)

</para>

</listitem>

<listitem>

<para>

Sync our copy of the timezone library with IANA release tzcode2017b

(Tom Lane)

</para>

<para>

This fixes a bug affecting some DST transitions in January 2038.

</para>

</listitem>

<listitem>

<para>

Update time zone data files to <application>tzdata</> release 2017b

for DST law changes in Chile, Haiti, and Mongolia, plus historical

corrections for Ecuador, Kazakhstan, Liberia, and Spain.

Switch to numeric abbreviations for numerous time zones in South

America, the Pacific and Indian oceans, and some Asian and Middle

Eastern countries.

</para>

<para>

The IANA time zone database previously provided textual abbreviations

for all time zones, sometimes making up abbreviations that have little

or no currency among the local population. They are in process of

reversing that policy in favor of using numeric UTC offsets in zones

where there is no evidence of real-world use of an English

abbreviation. At least for the time being, <productname>PostgreSQL</>

will continue to accept such removed abbreviations for timestamp input.

But they will not be shown in the <structname>pg_timezone_names</>

view nor used for output.

</para>

</listitem>

<listitem>

<para>

Use correct daylight-savings rules for POSIX-style time zone names

in MSVC builds (David Rowley)

</para>

<para>

The Microsoft MSVC build scripts neglected to install

the <filename>posixrules</> file in the timezone directory tree.

This resulted in the timezone code falling back to its built-in

rule about what DST behavior to assume for a POSIX-style time zone

name. For historical reasons that still corresponds to the DST rules

the USA was using before 2007 (i.e., change on first Sunday in April

and last Sunday in October). With this fix, a POSIX-style zone name

will use the current and historical DST transition dates of

the <literal>US/Eastern</> zone. If you don't want that, remove

the <filename>posixrules</> file, or replace it with a copy of some

other zone file (see <xref linkend="datatype-timezones">). Note that

due to caching, you may need to restart the server to get such changes

to take effect.

</para>

</listitem>

</itemizedlist>

</sect2>

</sect1>

<sect1 id="release-9-2-20">

<title>Release 9.2.20</title>