release-9.2.sgml 160.93 KiB
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<sect1 id="release-9-2-7">
<title>Release 9.2.7</title>
<note>
<title>Release Date</title>
<simpara>2014-02-20</simpara>
</note>
<para>
This release contains a variety of fixes from 9.2.6.
For information about new features in the 9.2 major release, see
<xref linkend="release-9-2">.
</para>
<sect2>
<title>Migration to Version 9.2.7</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 9.2.6,
see <xref linkend="release-9-2-6">.
</para>
</sect2>
<sect2>
<title>Changes</title>
<itemizedlist>
<listitem>
<para>
Fix possible mis-replay of WAL records when some segments of a
relation aren't full size (Greg Stark, Tom Lane)
</para>
<para>
The WAL update could be applied to the wrong page, potentially many
pages past where it should have been. Aside from corrupting data,
this error has been observed to result in significant <quote>bloat</>
of standby servers compared to their masters, due to updates being
applied far beyond where the end-of-file should have been. This
failure mode does not appear to be a significant risk during crash
recovery, only when initially synchronizing a standby created from a
base backup taken from a quickly-changing master.
</para>
</listitem>
<listitem>
<para>
Fix bug in determining when recovery has reached consistency
(Tomonari Katsumata, Heikki Linnakangas)
</para>
<para>
In some cases WAL replay would mistakenly conclude that the database
was already consistent at the start of replay, thus possibly allowing
hot-standby queries before the database was really consistent. Other
symptoms such as <quote>PANIC: WAL contains references to invalid
pages</> were also possible.
</para>
</listitem>
<listitem> <para>
Fix improper locking of btree index pages while replaying
a <literal>VACUUM</> operation in hot-standby mode (Andres Freund,
Heikki Linnakangas, Tom Lane)
</para>
<para>
This error could result in <quote>PANIC: WAL contains references to
invalid pages</> failures.
</para>
</listitem>
<listitem>
<para>
Ensure that insertions into non-leaf GIN index pages write a full-page
WAL record when appropriate (Heikki Linnakangas)
</para>
<para>
The previous coding risked index corruption in the event of a
partial-page write during a system crash.
</para>
</listitem>
<listitem>
<para>
When <literal>pause_at_recovery_target</>
and <literal>recovery_target_inclusive</> are both set, ensure the
target record is applied before pausing, not after (Heikki
Linnakangas)
</para>
</listitem>
<listitem>
<para>
Fix race conditions during server process exit (Robert Haas)
</para>
<para>
Ensure that signal handlers don't attempt to use the
process's <varname>MyProc</> pointer after it's no longer valid.
</para>
</listitem>
<listitem>
<para>
Fix race conditions in walsender shutdown logic and walreceiver
SIGHUP signal handler (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix unsafe references to <varname>errno</> within error reporting
logic (Christian Kruse)
</para>
<para>
This would typically lead to odd behaviors such as missing or
inappropriate <literal>HINT</> fields.
</para>
</listitem>
<listitem>
<para>
Fix possible crashes from using <function>ereport()</> too early
during server startup (Tom Lane)
</para>
<para> The principal case we've seen in the field is a crash if the server
is started in a directory it doesn't have permission to read.
</para>
</listitem>
<listitem>
<para>
Clear retry flags properly in OpenSSL socket write
function (Alexander Kukushkin)
</para>
<para>
This omission could result in a server lockup after unexpected loss
of an SSL-encrypted connection.
</para>
</listitem>
<listitem>
<para>
Fix length checking for Unicode identifiers (<literal>U&"..."</>
syntax) containing escapes (Tom Lane)
</para>
<para>
A spurious truncation warning would be printed for such identifiers
if the escaped form of the identifier was too long, but the
identifier actually didn't need truncation after de-escaping.
</para>
</listitem>
<listitem>
<para>
Allow keywords that are type names to be used in lists of roles
(Stephen Frost)
</para>
<para>
A previous patch allowed such keywords to be used without quoting
in places such as role identifiers; but it missed cases where a
list of role identifiers was permitted, such as <literal>DROP ROLE</>.
</para>
</listitem>
<listitem>
<para>
Fix parser crash for <literal>EXISTS(SELECT * FROM
zero_column_table)</literal> (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix possible crash due to invalid plan for nested sub-selects, such
as <literal>WHERE (... x IN (SELECT ...) ...) IN (SELECT ...)</>
(Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix <literal>UPDATE/DELETE</> of an inherited target table
that has <literal>UNION ALL</> subqueries (Tom Lane)
</para>
<para>
Without this fix, <literal>UNION ALL</> subqueries aren't correctly
inserted into the update plans for inheritance child tables after the
first one, typically resulting in no update happening for those child
table(s).
</para> </listitem>
<listitem>
<para>
Ensure that <command>ANALYZE</> creates statistics for a table column
even when all the values in it are <quote>too wide</> (Tom Lane)
</para>
<para>
<command>ANALYZE</> intentionally omits very wide values from its
histogram and most-common-values calculations, but it neglected to do
something sane in the case that all the sampled entries are too wide.
</para>
</listitem>
<listitem>
<para>
In <literal>ALTER TABLE ... SET TABLESPACE</>, allow the database's
default tablespace to be used without a permissions check
(Stephen Frost)
</para>
<para>
<literal>CREATE TABLE</> has always allowed such usage,
but <literal>ALTER TABLE</> didn't get the memo.
</para>
</listitem>
<listitem>
<para>
Fix <quote>cannot accept a set</> error when some arms of
a <literal>CASE</> return a set and others don't (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Properly distinguish numbers from non-numbers when generating JSON
output (Andrew Dunstan)
</para>
</listitem>
<listitem>
<para>
Fix checks for all-zero client addresses in pgstat functions (Kevin
Grittner)
</para>
</listitem>
<listitem>
<para>
Fix possible misclassification of multibyte characters by the text
search parser (Tom Lane)
</para>
<para>
Non-ASCII characters could be misclassified when using C locale with
a multibyte encoding. On Cygwin, non-C locales could fail as well.
</para>
</listitem>
<listitem>
<para>
Fix possible misbehavior in <function>plainto_tsquery()</>
(Heikki Linnakangas)
</para>
<para>
Use <function>memmove()</> not <function>memcpy()</> for copying
overlapping memory regions. There have been no field reports of this actually causing trouble, but it's certainly risky.
</para>
</listitem>
<listitem>
<para>
Fix placement of permissions checks in <function>pg_start_backup()</>
and <function>pg_stop_backup()</> (Andres Freund, Magnus Hagander)
</para>
<para>
The previous coding might attempt to do catalog access when it
shouldn't.
</para>
</listitem>
<listitem>
<para>
Accept <literal>SHIFT_JIS</> as an encoding name for locale checking
purposes (Tatsuo Ishii)
</para>
</listitem>
<listitem>
<para>
Fix <literal>*</>-qualification of named parameters in SQL-language
functions (Tom Lane)
</para>
<para>
Given a composite-type parameter
named <literal>foo</>, <literal>$1.*</> worked fine,
but <literal>foo.*</> not so much.
</para>
</listitem>
<listitem>
<para>
Fix misbehavior of <function>PQhost()</> on Windows (Fujii Masao)
</para>
<para>
It should return <literal>localhost</> if no host has been specified.
</para>
</listitem>
<listitem>
<para>
Improve error handling in <application>libpq</> and <application>psql</>
for failures during <literal>COPY TO STDOUT/FROM STDIN</> (Tom Lane)
</para>
<para>
In particular this fixes an infinite loop that could occur in 9.2 and
up if the server connection was lost during <literal>COPY FROM
STDIN</>. Variants of that scenario might be possible in older
versions, or with other client applications.
</para>
</listitem>
<listitem>
<para>
Fix incorrect translation handling in
some <application>psql</> <literal>\d</> commands
(Peter Eisentraut, Tom Lane)
</para>
<para>
</para>
</listitem>
<listitem>
<para>
Ensure <application>pg_basebackup</>'s background process is killed
when exiting its foreground process (Magnus Hagander)
</para>
</listitem>
<listitem>
<para>
Fix possible incorrect printing of filenames
in <application>pg_basebackup</>'s verbose mode (Magnus Hagander)
</para>
</listitem>
<listitem>
<para>
Avoid including tablespaces inside PGDATA twice in base backups
(Dimitri Fontaine, Magnus Hagander)
</para>
</listitem>
<listitem>
<para>
Fix misaligned descriptors in <application>ecpg</> (MauMau)
</para>
</listitem>
<listitem>
<para>
In <application>ecpg</>, handle lack of a hostname in the connection
parameters properly (Michael Meskes)
</para>
</listitem>
<listitem>
<para>
Fix performance regression in <filename>contrib/dblink</> connection
startup (Joe Conway)
</para>
<para>
Avoid an unnecessary round trip when client and server encodings match.
</para>
</listitem>
<listitem>
<para>
In <filename>contrib/isn</>, fix incorrect calculation of the check
digit for ISMN values (Fabien Coelho)
</para>
</listitem>
<listitem>
<para>
Fix <filename>contrib/pg_stat_statement</>'s handling
of <literal>CURRENT_DATE</> and related constructs (Kyotaro
Horiguchi)
</para>
</listitem>
<listitem>
<para>
Ensure client-code-only installation procedure works as documented
(Peter Eisentraut)
</para>
</listitem>
<listitem>
<para> In Mingw and Cygwin builds, install the <application>libpq</> DLL
in the <filename>bin</> directory (Andrew Dunstan)
</para>
<para>
This duplicates what the MSVC build has long done. It should fix
problems with programs like <application>psql</> failing to start
because they can't find the DLL.
</para>
</listitem>
<listitem>
<para>
Avoid using the deprecated <literal>dllwrap</> tool in Cygwin builds
(Marco Atzeri)
</para>
</listitem>
<listitem>
<para>
Don't generate plain-text <filename>HISTORY</>
and <filename>src/test/regress/README</> files anymore (Tom Lane)
</para>
<para>
These text files duplicated the main HTML and PDF documentation
formats. The trouble involved in maintaining them greatly outweighs
the likely audience for plain-text format. Distribution tarballs
will still contain files by these names, but they'll just be stubs
directing the reader to consult the main documentation.
The plain-text <filename>INSTALL</> file will still be maintained, as
there is arguably a use-case for that.
</para>
</listitem>
<listitem>
<para>
Update time zone data files to <application>tzdata</> release 2013i
for DST law changes in Jordan and historical changes in Cuba.
</para>
<para>
In addition, the zones <literal>Asia/Riyadh87</>,
<literal>Asia/Riyadh88</>, and <literal>Asia/Riyadh89</> have been
removed, as they are no longer maintained by IANA, and never
represented actual civil timekeeping practice.
</para>
</listitem>
</itemizedlist>
</sect2>
</sect1>
<sect1 id="release-9-2-6">
<title>Release 9.2.6</title>
<note>
<title>Release Date</title>
<simpara>2013-12-05</simpara>
</note>
<para>
This release contains a variety of fixes from 9.2.5.
For information about new features in the 9.2 major release, see
<xref linkend="release-9-2">.
</para>
<sect2>
<title>Migration to Version 9.2.6</title>
<para>
A dump/restore is not required for those running 9.2.X.
</para>
<para>
However, this release corrects a number of potential data corruption
issues. See the first two changelog entries 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 9.2.4,
see <xref linkend="release-9-2-4">.
</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. In 9.2.0
and later, the probability of loss is higher, and it's also possible
to get <quote>could not access status of transaction</> errors as a
consequence of this bug. Users upgrading from releases 9.0.4 or 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 initialization of <filename>pg_clog</> and <filename>pg_subtrans</>
during hot standby startup (Andres Freund, Heikki Linnakangas)
</para>
<para>
This bug can cause data loss on standby servers at the moment they
start to accept hot-standby queries, by marking committed transactions
as uncommitted. The likelihood of such corruption is small unless, at
the time of standby startup, the primary server has executed many
updating transactions since its last checkpoint. Symptoms include
missing rows, rows that should have been deleted being still visible,
and obsolete versions of updated rows being still visible alongside
their newer versions.
</para>
<para>
This bug was introduced in versions 9.3.0, 9.2.5, 9.1.10, and 9.0.14.
Standby servers that have only been running earlier releases are not
at risk. It's recommended that standby servers that have ever run any
of the buggy releases be re-cloned from the primary (e.g., with a new
base backup) after upgrading.
</para>
</listitem>
<listitem>
<para>
Fix dangling-pointer problem in fast-path locking (Tom Lane)
</para>
<para>
This could lead to corruption of the lock data structures in shared
memory, causing <quote>lock already held</> and other odd errors.
</para>
</listitem>
<listitem>
<para>
Truncate <filename>pg_multixact</> contents during WAL replay
(Andres Freund)
</para>
<para>
This avoids ever-increasing disk space consumption in standby servers.
</para>
</listitem>
<listitem>
<para>
Ensure an anti-wraparound <command>VACUUM</> counts a page as scanned
when it's only verified that no tuples need freezing (Sergey
Burladyan, Jeff Janes)
</para>
<para>
This bug could result in failing to
advance <structfield>relfrozenxid</>, so that the table would still be
thought to need another anti-wraparound vacuum. In the worst case the
database might even shut down to prevent wraparound.
</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>
Fix <quote>unexpected spgdoinsert() failure</> error during SP-GiST
index creation (Teodor Sigaev)
</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 incorrect planning in cases where the same non-strict expression
appears in multiple <literal>WHERE</> and outer <literal>JOIN</>
equality clauses (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix planner crash with whole-row reference to a subquery (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix incorrect generation of optimized MIN()/MAX() plans for
inheritance trees (Tom Lane)
</para>
<para>
The planner could fail in cases where the MIN()/MAX() argument was an
expression rather than a simple variable.
</para>
</listitem>
<listitem>
<para>
Fix premature deletion of temporary files (Andres Freund)
</para>
</listitem>
<listitem>
<para>
Prevent intra-transaction memory leak when printing range values
(Tom Lane)
</para>
<para>
This fix actually cures transient memory leaks in any datatype output
function, but range types are the only ones known to have had a
significant problem.
</para>
</listitem>
<listitem>
<para>
Prevent incorrect display of dropped columns in NOT NULL and CHECK
constraint violation messages (Michael Paquier and Tom Lane)
</para>
</listitem>
<listitem>
<para>
Allow default arguments and named-argument notation for window
functions (Tom Lane)
</para>
<para>
Previously, these cases were likely to crash.
</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>
Make <application>ecpg</> search for quoted cursor names
case-sensitively (Zoltán Böszörményi)
</para>
</listitem>
<listitem>
<para>
Fix <application>ecpg</>'s processing of lists of variables
declared <type>varchar</> (Zoltán Böszörményi)
</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>
<sect1 id="release-9-2-5">
<title>Release 9.2.5</title>
<note>
<title>Release Date</title>
<simpara>2013-10-10</simpara>
</note>
<para>
This release contains a variety of fixes from 9.2.4.
For information about new features in the 9.2 major release, see
<xref linkend="release-9-2">.
</para>
<sect2>
<title>Migration to Version 9.2.5</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 9.2.4,
see <xref linkend="release-9-2-4">.
</para>
</sect2>
<sect2> <title>Changes</title>
<itemizedlist>
<listitem>
<para>
Prevent corruption of multi-byte characters when attempting to
case-fold identifiers (Andrew Dunstan)
</para>
<para>
<productname>PostgreSQL</> case-folds non-ASCII characters only
when using a single-byte server encoding.
</para>
</listitem>
<listitem>
<para>
Fix memory leak when creating B-tree indexes on range columns
(Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Fix checkpoint memory leak in background writer when <literal>wal_level =
hot_standby</> (Naoya Anzai)
</para>
</listitem>
<listitem>
<para>
Fix memory leak caused by <function>lo_open()</function> failure
(Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Fix memory overcommit bug when <varname>work_mem</> is using more
than 24GB of memory (Stephen Frost)
</para>
</listitem>
<listitem>
<para>
Serializable snapshot fixes (Kevin Grittner, Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Fix deadlock bug in libpq when using SSL (Stephen Frost)
</para>
</listitem>
<listitem>
<para>
Fix possible SSL state corruption in threaded libpq applications
(Nick Phillips, Stephen Frost)
</para>
</listitem>
<listitem>
<para>
Improve estimate of planner cost when choosing between generic and
custom plans (Tom Lane)
</para>
<para> This change will favor generic plans when planning cost is high.
</para>
</listitem>
<listitem>
<para>
Properly compute row estimates for boolean columns containing many NULL
values (Andrew Gierth)
</para>
<para>
Previously tests like <literal>col IS NOT TRUE</> and <literal>col IS
NOT FALSE</> did not properly factor in NULL values when estimating
plan costs.
</para>
</listitem>
<listitem>
<para>
Fix accounting for qualifier evaluation costs in <literal>UNION ALL</>
and inheritance queries (Tom Lane)
</para>
<para>
This fixes cases where suboptimal query plans could be chosen if
some <literal>WHERE</> clauses are expensive to calculate.
</para>
</listitem>
<listitem>
<para>
Prevent pushing down <literal>WHERE</> clauses into unsafe
<literal>UNION/INTERSECT</> subqueries (Tom Lane)
</para>
<para>
Subqueries of a <literal>UNION</> or <literal>INTERSECT</> that
contain set-returning functions or volatile functions in their
<literal>SELECT</> lists could be improperly optimized, leading to
run-time errors or incorrect query results.
</para>
</listitem>
<listitem>
<para>
Fix rare case of <quote>failed to locate grouping columns</>
planner failure (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix <application>pg_dump</> of foreign tables with dropped columns (Andrew Dunstan)
</para>
<para>
Previously such cases could cause a <application>pg_upgrade</> error.
</para>
</listitem>
<listitem>
<para>
Reorder <application>pg_dump</> processing of extension-related
rules and event triggers (Joe Conway)
</para>
</listitem>
<listitem>
<para>
Force dumping of extension tables if specified by <command>pg_dump -t</> or <literal>-n</> (Joe Conway)
</para>
</listitem>
<listitem>
<para>
Improve view dumping code's handling of dropped columns in referenced
tables (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix <command>pg_restore -l</> with the directory archive to display
the correct format name (Fujii Masao)
</para>
</listitem>
<listitem>
<para>
Properly record index comments created using <literal>UNIQUE</>
and <literal>PRIMARY KEY</> syntax (Andres Freund)
</para>
<para>
This fixes a parallel <application>pg_restore</> failure.
</para>
</listitem>
<listitem>
<para>
Cause <command>pg_basebackup -x</> with an empty xlog directory
to throw an error rather than crashing (Magnus Hagander, Haruka
Takatsuka)
</para>
</listitem>
<listitem>
<para>
Properly guarantee transmission of WAL files before clean switchover
(Fujii Masao)
</para>
<para>
Previously, the streaming replication connection might close before all
WAL files had been replayed on the standby.
</para>
</listitem>
<listitem>
<para>
Fix WAL segment timeline handling during recovery (Mitsumasa Kondo,
Heikki Linnakangas)
</para>
<para>
WAL file recycling during standby recovery could lead to premature
recovery completion, resulting in data loss.
</para>
</listitem>
<listitem>
<para>
Fix <command>REINDEX TABLE</> and <command>REINDEX DATABASE</>
to properly revalidate constraints and mark invalidated indexes as
valid (Noah Misch)
</para>
<para>
<command>REINDEX INDEX</> has always worked properly. </para>
</listitem>
<listitem>
<para>
Avoid deadlocks during insertion into SP-GiST indexes (Teodor Sigaev)
</para>
</listitem>
<listitem>
<para>
Fix possible deadlock during concurrent <command>CREATE INDEX
CONCURRENTLY</> operations (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix GiST index lookup crash (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix <function>regexp_matches()</> handling of zero-length matches
(Jeevan Chalke)
</para>
<para>
Previously, zero-length matches like '^' could return too many matches.
</para>
</listitem>
<listitem>
<para>
Fix crash for overly-complex regular expressions (Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Fix regular expression match failures for back references combined with
non-greedy quantifiers (Jeevan Chalke)
</para>
</listitem>
<listitem>
<para>
Prevent <command>CREATE FUNCTION</> from checking <command>SET</>
variables unless function body checking is enabled (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Allow <command>ALTER DEFAULT PRIVILEGES</> to operate on schemas
without requiring CREATE permission (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Loosen restriction on keywords used in queries (Tom Lane)
</para>
<para>
Specifically, lessen keyword restrictions for role names, language
names, <command>EXPLAIN</> and <command>COPY</> options, and
<command>SET</> values. This allows <literal>COPY ... (FORMAT
BINARY)</> to work as expected; previously <literal>BINARY</> needed to be quoted.
</para>
</listitem>
<listitem>
<para>
Print proper line number during <command>COPY</> failure (Heikki
Linnakangas)
</para>
</listitem>
<listitem>
<para>
Fix <function>pgp_pub_decrypt()</> so it works for secret keys with
passwords (Marko Kreen)
</para>
</listitem>
<listitem>
<para>
Make <application>pg_upgrade</> use <literal>pg_dump
--quote-all-identifiers</> to avoid problems with keyword changes
between releases (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Remove rare inaccurate warning during vacuum of index-less tables
(Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Ensure that <command>VACUUM ANALYZE</> still runs the ANALYZE phase
if its attempt to truncate the file is cancelled due to lock conflicts
(Kevin Grittner)
</para>
</listitem>
<listitem>
<para>
Avoid possible failure when performing transaction control commands (e.g
<command>ROLLBACK</>) in prepared queries (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Ensure that floating-point data input accepts standard spellings
of <quote>infinity</> on all platforms (Tom Lane)
</para>
<para>
The C99 standard says that allowable spellings are <literal>inf</>,
<literal>+inf</>, <literal>-inf</>, <literal>infinity</>,
<literal>+infinity</>, and <literal>-infinity</>. Make sure we
recognize these even if the platform's <function>strtod</> function
doesn't.
</para>
</listitem>
<listitem>
<para>
Avoid unnecessary reporting when <varname>track_activities</> is off
(Tom Lane)
</para>
</listitem>
<listitem>
<para>
Expand ability to compare rows to records and arrays (Rafal Rzepecki,
Tom Lane)
</para>
</listitem>
<listitem>
<para>
Prevent crash when <application>psql</>'s <envar>PSQLRC</> variable
contains a tilde (Bruce Momjian)
</para>
</listitem>
<listitem>
<para>
Add spinlock support for ARM64 (Mark Salter)
</para>
</listitem>
<listitem>
<para>
Update time zone data files to <application>tzdata</> release 2013d
for DST law changes in Israel, Morocco, Palestine, and Paraguay.
Also, historical zone data corrections for Macquarie Island.
</para>
</listitem>
</itemizedlist>
</sect2>
</sect1>
<sect1 id="release-9-2-4">
<title>Release 9.2.4</title>
<note>
<title>Release Date</title>
<simpara>2013-04-04</simpara>
</note>
<para>
This release contains a variety of fixes from 9.2.3.
For information about new features in the 9.2 major release, see
<xref linkend="release-9-2">.
</para>
<sect2>
<title>Migration to Version 9.2.4</title>
<para>
A dump/restore is not required for those running 9.2.X.
</para>
<para>
However, this release corrects several errors in management of GiST
indexes. After installing this update, it is advisable to
<command>REINDEX</> any GiST indexes that meet one or more of the
conditions described below.
</para>
<para>
Also, if you are upgrading from a version earlier than 9.2.2,
see <xref linkend="release-9-2-2">.
</para>
</sect2>
<sect2>
<title>Changes</title>
<itemizedlist>
<listitem>
<para>
Fix insecure parsing of server command-line switches (Mitsumasa
Kondo, Kyotaro Horiguchi)
</para>
<para>
A connection request containing a database name that begins with
<quote><literal>-</></quote> could be crafted to damage or destroy
files within the server's data directory, even if the request is
eventually rejected. (CVE-2013-1899)
</para>
</listitem>
<listitem>
<para>
Reset OpenSSL randomness state in each postmaster child process
(Marko Kreen)
</para>
<para>
This avoids a scenario wherein random numbers generated by
<filename>contrib/pgcrypto</> functions might be relatively easy for
another database user to guess. The risk is only significant when
the postmaster is configured with <varname>ssl</> = <literal>on</>
but most connections don't use SSL encryption. (CVE-2013-1900)
</para>
</listitem>
<listitem>
<para>
Make REPLICATION privilege checks test current user not authenticated
user (Noah Misch)
</para>
<para>
An unprivileged database user could exploit this mistake to call
<function>pg_start_backup()</> or <function>pg_stop_backup()</>,
thus possibly interfering with creation of routine backups.
(CVE-2013-1901)
</para>
</listitem>
<listitem>
<para>
Fix GiST indexes to not use <quote>fuzzy</> geometric comparisons when
it's not appropriate to do so (Alexander Korotkov)
</para>
<para>
The core geometric types perform comparisons using <quote>fuzzy</>
equality, but <function>gist_box_same</> must do exact comparisons,
else GiST indexes using it might become inconsistent. After installing
this update, users should <command>REINDEX</> any GiST indexes on
<type>box</>, <type>polygon</>, <type>circle</>, or <type>point</>
columns, since all of these use <function>gist_box_same</>.
</para>
</listitem>
<listitem>
<para>
Fix erroneous range-union and penalty logic in GiST indexes that use
<filename>contrib/btree_gist</> for variable-width data types, that is
<type>text</>, <type>bytea</>, <type>bit</>, and <type>numeric</>
columns (Tom Lane)
</para>
<para>
These errors could result in inconsistent indexes in which some keys
that are present would not be found by searches, and also in useless
index bloat. Users are advised to <command>REINDEX</> such indexes
after installing this update.
</para>
</listitem>
<listitem>
<para>
Fix bugs in GiST page splitting code for multi-column indexes
(Tom Lane)
</para>
<para>
These errors could result in inconsistent indexes in which some keys
that are present would not be found by searches, and also in indexes
that are unnecessarily inefficient to search. Users are advised to
<command>REINDEX</> multi-column GiST indexes after installing this
update.
</para>
</listitem>
<listitem>
<para>
Fix <function>gist_point_consistent</>
to handle fuzziness consistently (Alexander Korotkov)
</para>
<para>
Index scans on GiST indexes on <type>point</> columns would sometimes
yield results different from a sequential scan, because
<function>gist_point_consistent</> disagreed with the underlying
operator code about whether to do comparisons exactly or fuzzily.
</para>
</listitem>
<listitem>
<para>
Fix buffer leak in WAL replay (Heikki Linnakangas)
</para>
<para>
This bug could result in <quote>incorrect local pin count</> errors
during replay, making recovery impossible.
</para>
</listitem>
<listitem>
<para>
Ensure we do crash recovery before entering archive recovery, if the
database was not stopped cleanly and a <filename>recovery.conf</> file
is present (Heikki Linnakangas, Kyotaro Horiguchi, Mitsumasa Kondo)
</para>
<para>
This is needed to ensure that the database is consistent in certain
scenarios, such as initializing a standby server with a filesystem
snapshot from a running server.
</para>
</listitem>
<listitem>
<para>
Avoid deleting not-yet-archived WAL files during crash recovery
(Heikki Linnakangas, Fujii Masao)
</para>
</listitem>
<listitem> <para>
Fix race condition in <command>DELETE RETURNING</> (Tom Lane)
</para>
<para>
Under the right circumstances, <command>DELETE RETURNING</> could
attempt to fetch data from a shared buffer that the current process
no longer has any pin on. If some other process changed the buffer
meanwhile, this would lead to garbage <literal>RETURNING</> output, or
even a crash.
</para>
</listitem>
<listitem>
<para>
Fix infinite-loop risk in regular expression compilation (Tom Lane,
Don Porter)
</para>
</listitem>
<listitem>
<para>
Fix potential null-pointer dereference in regular expression compilation
(Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix <function>to_char()</> to use ASCII-only case-folding rules where
appropriate (Tom Lane)
</para>
<para>
This fixes misbehavior of some template patterns that should be
locale-independent, but mishandled <quote><literal>I</></quote> and
<quote><literal>i</></quote> in Turkish locales.
</para>
</listitem>
<listitem>
<para>
Fix unwanted rejection of timestamp <literal>1999-12-31 24:00:00</>
(Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix SQL-language functions to be safely usable as support
functions for range types (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix logic error when a single transaction does <command>UNLISTEN</>
then <command>LISTEN</> (Tom Lane)
</para>
<para>
The session wound up not listening for notify events at all, though it
surely should listen in this case.
</para>
</listitem>
<listitem>
<para>
Fix possible planner crash after columns have been added to a view
that's depended on by another view (Tom Lane) </para>
</listitem>
<listitem>
<para>
Fix performance issue in <literal>EXPLAIN (ANALYZE, TIMING OFF)</>
(Pavel Stehule)
</para>
</listitem>
<listitem>
<para>
Remove useless <quote>picksplit doesn't support secondary split</> log
messages (Josh Hansen, Tom Lane)
</para>
<para>
This message seems to have been added in expectation of code that was
never written, and probably never will be, since GiST's default
handling of secondary splits is actually pretty good. So stop nagging
end users about it.
</para>
</listitem>
<listitem>
<para>
Remove vestigial secondary-split support in
<function>gist_box_picksplit()</> (Tom Lane)
</para>
<para>
Not only was this implementation of secondary-split not better than the
default implementation, it's actually worse. So remove it and let the
default code path handle the case.
</para>
</listitem>
<listitem>
<para>
Fix possible failure to send a session's last few transaction
commit/abort counts to the statistics collector (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Eliminate memory leaks in PL/Perl's <function>spi_prepare()</> function
(Alex Hunsaker, Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix <application>pg_dumpall</> to handle database names containing
<quote><literal>=</></quote> correctly (Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Avoid crash in <application>pg_dump</> when an incorrect connection
string is given (Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Ignore invalid indexes in <application>pg_dump</> and
<application>pg_upgrade</> (Michael Paquier, Bruce Momjian)
</para>
<para>
Dumping invalid indexes can cause problems at restore time, for example
if the reason the index creation failed was because it tried to enforce
a uniqueness condition not satisfied by the table's data. Also, if the
index creation is in fact still in progress, it seems reasonable to
consider it to be an uncommitted DDL change, which
<application>pg_dump</> wouldn't be expected to dump anyway.
<application>pg_upgrade</> now also skips invalid indexes rather than
failing.
</para>
</listitem>
<listitem>
<para>
In <application>pg_basebackup</>, include only the current server
version's subdirectory when backing up a tablespace (Heikki
Linnakangas)
</para>
</listitem>
<listitem>
<para>
Add a server version check in <application>pg_basebackup</> and
<application>pg_receivexlog</>, so they fail cleanly with version
combinations that won't work (Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Fix <filename>contrib/dblink</> to handle inconsistent settings of
<varname>DateStyle</> or <varname>IntervalStyle</> safely (Daniel
Farina, Tom Lane)
</para>
<para>
Previously, if the remote server had different settings of these
parameters, ambiguous dates might be read incorrectly. This fix
ensures that datetime and interval columns fetched by a
<filename>dblink</> query will be interpreted correctly. Note however
that inconsistent settings are still risky, since literal values
appearing in SQL commands sent to the remote server might be
interpreted differently than they would be locally.
</para>
</listitem>
<listitem>
<para>
Fix <filename>contrib/pg_trgm</>'s <function>similarity()</> function
to return zero for trigram-less strings (Tom Lane)
</para>
<para>
Previously it returned <literal>NaN</> due to internal division by zero.
</para>
</listitem>
<listitem>
<para>
Enable building <productname>PostgreSQL</> with Microsoft Visual
Studio 2012 (Brar Piening, Noah Misch)
</para>
</listitem>
<listitem>
<para>
Update time zone data files to <application>tzdata</> release 2013b
for DST law changes in Chile, Haiti, Morocco, Paraguay, and some
Russian areas. Also, historical zone data corrections for numerous places.
</para>
<para>
Also, update the time zone abbreviation files for recent changes in
Russia and elsewhere: <literal>CHOT</>, <literal>GET</>,
<literal>IRKT</>, <literal>KGT</>, <literal>KRAT</>, <literal>MAGT</>,
<literal>MAWT</>, <literal>MSK</>, <literal>NOVT</>, <literal>OMST</>,
<literal>TKT</>, <literal>VLAT</>, <literal>WST</>, <literal>YAKT</>,
<literal>YEKT</> now follow their current meanings, and
<literal>VOLT</> (Europe/Volgograd) and <literal>MIST</>
(Antarctica/Macquarie) are added to the default abbreviations list.
</para>
</listitem>
</itemizedlist>
</sect2>
</sect1>
<sect1 id="release-9-2-3">
<title>Release 9.2.3</title>
<note>
<title>Release Date</title>
<simpara>2013-02-07</simpara>
</note>
<para>
This release contains a variety of fixes from 9.2.2.
For information about new features in the 9.2 major release, see
<xref linkend="release-9-2">.
</para>
<sect2>
<title>Migration to Version 9.2.3</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 9.2.2,
see <xref linkend="release-9-2-2">.
</para>
</sect2>
<sect2>
<title>Changes</title>
<itemizedlist>
<listitem>
<para>
Prevent execution of <function>enum_recv</> from SQL (Tom Lane)
</para>
<para>
The function was misdeclared, allowing a simple SQL command to crash the
server. In principle an attacker might be able to use it to examine the
contents of server memory. Our thanks to Sumit Soni (via Secunia SVCRP)
for reporting this issue. (CVE-2013-0255)
</para>
</listitem>
<listitem>
<para>
Fix multiple problems in detection of when a consistent database
state has been reached during WAL replay (Fujii Masao, Heikki Linnakangas, Simon Riggs, Andres Freund)
</para>
</listitem>
<listitem>
<para>
Fix detection of end-of-backup point when no actual redo work is
required (Heikki Linnakangas)
</para>
<para>
This mistake could result in incorrect <quote>WAL ends before end of
online backup</> errors.
</para>
</listitem>
<listitem>
<para>
Update minimum recovery point when truncating a relation file (Heikki
Linnakangas)
</para>
<para>
Once data has been discarded, it's no longer safe to stop recovery at
an earlier point in the timeline.
</para>
</listitem>
<listitem>
<para>
Fix recycling of WAL segments after changing recovery target timeline
(Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Properly restore timeline history files from archive on cascading
standby servers (Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Fix lock conflict detection on hot-standby servers (Andres Freund,
Robert Haas)
</para>
</listitem>
<listitem>
<para>
Fix missing cancellations in hot standby mode (Noah Misch, Simon Riggs)
</para>
<para>
The need to cancel conflicting hot-standby queries would sometimes be
missed, allowing those queries to see inconsistent data.
</para>
</listitem>
<listitem>
<para>
Prevent recovery pause feature from pausing before users can connect
(Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix SQL grammar to allow subscripting or field selection from a sub-SELECT result (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix performance problems with autovacuum truncation in busy workloads
(Jan Wieck)
</para>
<para>
Truncation of empty pages at the end of a table requires exclusive
lock, but autovacuum was coded to fail (and release the table lock)
when there are conflicting lock requests. Under load, it is easily
possible that truncation would never occur, resulting in table bloat.
Fix by performing a partial truncation, releasing the lock, then
attempting to re-acquire the lock and continue. This fix also greatly
reduces the average time before autovacuum releases the lock after a
conflicting request arrives.
</para>
</listitem>
<listitem>
<para>
Improve performance of <function>SPI_execute</> and related
functions, thereby improving PL/pgSQL's <literal>EXECUTE</>
(Heikki Linnakangas, Tom Lane)
</para>
<para>
Remove some data-copying overhead that was added in 9.2 as a
consequence of revisions in the plan caching mechanism. This
eliminates a performance regression compared to 9.1, and also saves
memory, especially when the query string to be executed contains many
SQL statements.
</para>
<para>
A side benefit is that multi-statement query strings are now
processed fully serially, that is we complete execution of earlier
statements before running parse analysis and planning on the
following ones. This eliminates a long-standing issue, in that DDL
that should affect the behavior of a later statement will now behave as
expected.
</para>
</listitem>
<listitem>
<para>
Restore pre-9.2 cost estimates for index usage (Tom Lane)
</para>
<para>
An ill-considered change of a fudge factor led to undesirably high
cost estimates for use of very large indexes.
</para>
</listitem>
<listitem>
<para>
Fix intermittent crash in <literal>DROP INDEX CONCURRENTLY</> (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix potential corruption of shared-memory lock table during
<command>CREATE/DROP INDEX CONCURRENTLY</> (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix <command>COPY</>'s multiple-tuple-insertion code for the case of
a tuple larger than page size minus fillfactor (Heikki Linnakangas)
</para>
<para>
The previous coding could get into an infinite loop.
</para>
</listitem>
<listitem>
<para>
Protect against race conditions when scanning
<structname>pg_tablespace</> (Stephen Frost, Tom Lane)
</para>
<para>
<command>CREATE DATABASE</> and <command>DROP DATABASE</> could
misbehave if there were concurrent updates of
<structname>pg_tablespace</> entries.
</para>
</listitem>
<listitem>
<para>
Prevent <command>DROP OWNED</> from trying to drop whole databases or
tablespaces (Álvaro Herrera)
</para>
<para>
For safety, ownership of these objects must be reassigned, not dropped.
</para>
</listitem>
<listitem>
<para>
Fix error in <link
linkend="guc-vacuum-freeze-table-age"><varname>vacuum_freeze_table_age</></link>
implementation (Andres Freund)
</para>
<para>
In installations that have existed for more than <link
linkend="guc-vacuum-freeze-min-age"><varname>vacuum_freeze_min_age</></link>
transactions, this mistake prevented autovacuum from using partial-table
scans, so that a full-table scan would always happen instead.
</para>
</listitem>
<listitem>
<para>
Prevent misbehavior when a <symbol>RowExpr</> or <symbol>XmlExpr</>
is parse-analyzed twice (Andres Freund, Tom Lane)
</para>
<para>
This mistake could be user-visible in contexts such as
<literal>CREATE TABLE LIKE INCLUDING INDEXES</>.
</para>
</listitem>
<listitem>
<para>
Improve defenses against integer overflow in hashtable sizing
calculations (Jeff Davis)
</para>
</listitem>
<listitem>
<para>
Fix some bugs associated with privileges on datatypes (Tom Lane)
</para>
<para>
There were some issues with default privileges for types, and
<application>pg_dump</> failed to dump such privileges at all.
</para>
</listitem>
<listitem>
<para>
Fix failure to ignore leftover temporary tables after a server crash
(Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix failure to rotate postmaster log files for size reasons on
Windows (Jeff Janes, Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Reject out-of-range dates in <function>to_date()</> (Hitoshi Harada)
</para>
</listitem>
<listitem>
<para>
Fix <function>pg_extension_config_dump()</> to handle
extension-update cases properly (Tom Lane)
</para>
<para>
This function will now replace any existing entry for the target
table, making it usable in extension update scripts.
</para>
</listitem>
<listitem>
<para>
Fix PL/pgSQL's reporting of plan-time errors in possibly-simple
expressions (Tom Lane)
</para>
<para>
The previous coding resulted in sometimes omitting the first line in
the <literal>CONTEXT</> traceback for the error.
</para>
</listitem>
<listitem>
<para>
Fix PL/Python's handling of functions used as triggers on multiple
tables (Andres Freund)
</para>
</listitem>
<listitem>
<para>
Ensure that non-ASCII prompt strings are translated to the correct
code page on Windows (Alexander Law, Noah Misch)
</para>
<para>
This bug affected <application>psql</> and some other client programs. </para>
</listitem>
<listitem>
<para>
Fix possible crash in <application>psql</>'s <command>\?</> command
when not connected to a database (Meng Qingzhong)
</para>
</listitem>
<listitem>
<para>
Fix possible error if a relation file is removed while
<application>pg_basebackup</> is running (Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Tolerate timeline switches while <literal>pg_basebackup -X fetch</>
is backing up a standby server (Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Make <application>pg_dump</> exclude data of unlogged tables when
running on a hot-standby server (Magnus Hagander)
</para>
<para>
This would fail anyway because the data is not available on the standby
server, so it seems most convenient to assume
<option>--no-unlogged-table-data</> automatically.
</para>
</listitem>
<listitem>
<para>
Fix <application>pg_upgrade</> to deal with invalid indexes safely
(Bruce Momjian)
</para>
</listitem>
<listitem>
<para>
Fix <application>pg_upgrade</>'s -O/-o options (Marti Raudsepp)
</para>
</listitem>
<listitem>
<para>
Fix one-byte buffer overrun in <application>libpq</>'s
<function>PQprintTuples</> (Xi Wang)
</para>
<para>
This ancient function is not used anywhere by
<productname>PostgreSQL</> itself, but it might still be used by some
client code.
</para>
</listitem>
<listitem>
<para>
Make <application>ecpglib</> use translated messages properly
(Chen Huajun)
</para>
</listitem>
<listitem>
<para>
Properly install <application>ecpg_compat</> and
<application>pgtypes</> libraries on MSVC (Jiang Guiqing)
</para>
</listitem>
<listitem>
<para>
Include our version of <function>isinf()</> in
<application>libecpg</> if it's not provided by the system
(Jiang Guiqing)
</para>
</listitem>
<listitem>
<para>
Rearrange configure's tests for supplied functions so it is not
fooled by bogus exports from libedit/libreadline (Christoph Berg)
</para>
</listitem>
<listitem>
<para>
Ensure Windows build number increases over time (Magnus Hagander)
</para>
</listitem>
<listitem>
<para>
Make <application>pgxs</> build executables with the right
<literal>.exe</> suffix when cross-compiling for Windows
(Zoltan Boszormenyi)
</para>
</listitem>
<listitem>
<para>
Add new timezone abbreviation <literal>FET</> (Tom Lane)
</para>
<para>
This is now used in some eastern-European time zones.
</para>
</listitem>
</itemizedlist>
</sect2>
</sect1>
<sect1 id="release-9-2-2">
<title>Release 9.2.2</title>
<note>
<title>Release Date</title>
<simpara>2012-12-06</simpara>
</note>
<para>
This release contains a variety of fixes from 9.2.1.
For information about new features in the 9.2 major release, see
<xref linkend="release-9-2">.
</para>
<sect2>
<title>Migration to Version 9.2.2</title>
<para>
A dump/restore is not required for those running 9.2.X. </para>
<para>
However, you may need to perform <command>REINDEX</> operations to
correct problems in concurrently-built indexes, as described in the first
changelog item below.
</para>
<para>
Also, if you are upgrading from version 9.2.0,
see <xref linkend="release-9-2-1">.
</para>
</sect2>
<sect2>
<title>Changes</title>
<itemizedlist>
<listitem>
<para>
Fix multiple bugs associated with <command>CREATE/DROP INDEX
CONCURRENTLY</> (Andres Freund, Tom Lane, Simon Riggs, Pavan Deolasee)
</para>
<para>
An error introduced while adding <command>DROP INDEX CONCURRENTLY</>
allowed incorrect indexing decisions to be made during the initial
phase of <command>CREATE INDEX CONCURRENTLY</>; so that indexes built
by that command could be corrupt. It is recommended that indexes
built in 9.2.X with <command>CREATE INDEX CONCURRENTLY</> be rebuilt
after applying this update.
</para>
<para>
In addition, fix <command>CREATE/DROP INDEX CONCURRENTLY</> to use
in-place updates when changing the state of an index's
<structname>pg_index</> row. This prevents race conditions that could
cause concurrent sessions to miss updating the target index, thus
again resulting in corrupt concurrently-created indexes.
</para>
<para>
Also, fix various other operations to ensure that they ignore
invalid indexes resulting from a failed <command>CREATE INDEX
CONCURRENTLY</> command. The most important of these is
<command>VACUUM</>, because an auto-vacuum could easily be launched
on the table before corrective action can be taken to fix or remove
the invalid index.
</para>
<para>
Also fix <command>DROP INDEX CONCURRENTLY</> to not disable
insertions into the target index until all queries using it are done.
</para>
<para>
Also fix misbehavior if <command>DROP INDEX CONCURRENTLY</> is
canceled: the previous coding could leave an un-droppable index behind.
</para>
</listitem>
<listitem>
<para>
Correct predicate locking for <command>DROP INDEX CONCURRENTLY</>
(Kevin Grittner)
</para>
<para> Previously, SSI predicate locks were processed at the wrong time,
possibly leading to incorrect behavior of serializable transactions
executing in parallel with the <command>DROP</>.
</para>
</listitem>
<listitem>
<para>
Fix buffer locking during WAL replay (Tom Lane)
</para>
<para>
The WAL replay code was insufficiently careful about locking buffers
when replaying WAL records that affect more than one page. This could
result in hot standby queries transiently seeing inconsistent states,
resulting in wrong answers or unexpected failures.
</para>
</listitem>
<listitem>
<para>
Fix an error in WAL generation logic for GIN indexes (Tom Lane)
</para>
<para>
This could result in index corruption, if a torn-page failure occurred.
</para>
</listitem>
<listitem>
<para>
Fix an error in WAL replay logic for SP-GiST indexes (Tom Lane)
</para>
<para>
This could result in index corruption after a crash, or on a standby
server.
</para>
</listitem>
<listitem>
<para>
Fix incorrect detection of end-of-base-backup location during WAL
recovery (Heikki Linnakangas)
</para>
<para>
This mistake allowed hot standby mode to start up before the database
reaches a consistent state.
</para>
</listitem>
<listitem>
<para>
Properly remove startup process's virtual XID lock when promoting a
hot standby server to normal running (Simon Riggs)
</para>
<para>
This oversight could prevent subsequent execution of certain
operations such as <command>CREATE INDEX CONCURRENTLY</>.
</para>
</listitem>
<listitem>
<para>
Avoid bogus <quote>out-of-sequence timeline ID</> errors in standby
mode (Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Prevent the postmaster from launching new child processes after it's
received a shutdown signal (Tom Lane)
</para>
<para>
This mistake could result in shutdown taking longer than it should, or
even never completing at all without additional user action.
</para>
</listitem>
<listitem>
<para>
Fix the syslogger process to not fail when
<varname>log_rotation_age</> exceeds 2^31 milliseconds (about 25 days)
(Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix <function>WaitLatch()</> to return promptly when the requested
timeout expires (Jeff Janes, Tom Lane)
</para>
<para>
With the previous coding, a steady stream of non-wait-terminating
interrupts could delay return from <function>WaitLatch()</>
indefinitely. This has been shown to be a problem for the autovacuum
launcher process, and might cause trouble elsewhere as well.
</para>
</listitem>
<listitem>
<para>
Avoid corruption of internal hash tables when out of memory
(Hitoshi Harada)
</para>
</listitem>
<listitem>
<para>
Prevent file descriptors for dropped tables from being held open past
transaction end (Tom Lane)
</para>
<para>
This should reduce problems with long-since-dropped tables continuing
to occupy disk space.
</para>
</listitem>
<listitem>
<para>
Prevent database-wide crash and restart when a new child process is
unable to create a pipe for its latch (Tom Lane)
</para>
<para>
Although the new process must fail, there is no good reason to force a
database-wide restart, so avoid that. This improves robustness when
the kernel is nearly out of file descriptors.
</para>
</listitem>
<listitem>
<para>
Avoid planner crash with joins to unflattened subqueries (Tom Lane) </para>
</listitem>
<listitem>
<para>
Fix planning of non-strict equivalence clauses above outer joins
(Tom Lane)
</para>
<para>
The planner could derive incorrect constraints from a clause equating
a non-strict construct to something else, for example
<literal>WHERE COALESCE(foo, 0) = 0</>
when <literal>foo</> is coming from the nullable side of an outer join.
9.2 showed this type of error in more cases than previous releases,
but the basic bug has been there for a long time.
</para>
</listitem>
<listitem>
<para>
Fix <command>SELECT DISTINCT</> with index-optimized
<function>MIN</>/<function>MAX</> on an inheritance tree (Tom Lane)
</para>
<para>
The planner would fail with <quote>failed to re-find MinMaxAggInfo
record</> given this combination of factors.
</para>
</listitem>
<listitem>
<para>
Make sure the planner sees implicit and explicit casts as equivalent
for all purposes, except in the minority of cases where there's
actually a semantic difference (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Include join clauses when considering whether partial indexes can be
used for a query (Tom Lane)
</para>
<para>
A strict join clause can be sufficient to establish an
<replaceable>x</> <literal>IS NOT NULL</> predicate, for example.
This fixes a planner regression in 9.2, since previous versions could
make comparable deductions.
</para>
</listitem>
<listitem>
<para>
Limit growth of planning time when there are many indexable join
clauses for the same index (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Improve planner's ability to prove exclusion constraints from
equivalence classes (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix partial-row matching in hashed subplans to handle cross-type cases correctly (Tom Lane)
</para>
<para>
This affects multicolumn <literal>NOT IN</> subplans, such as
<literal>WHERE (a, b) NOT IN (SELECT x, y FROM ...)</>
when for instance <literal>b</> and <literal>y</> are <type>int4</>
and <type>int8</> respectively. This mistake led to wrong answers
or crashes depending on the specific datatypes involved.
</para>
</listitem>
<listitem>
<para>
Fix btree mark/restore functions to handle array keys (Tom Lane)
</para>
<para>
This oversight could result in wrong answers from merge joins whose
inner side is an index scan using an
<literal><replaceable>indexed_column</> =
ANY(<replaceable>array</>)</literal> condition.
</para>
</listitem>
<listitem>
<para>
Revert patch for taking fewer snapshots (Tom Lane)
</para>
<para>
The 9.2 change to reduce the number of snapshots taken during query
execution led to some anomalous behaviors not seen in previous
releases, because execution would proceed with a snapshot acquired
before locking the tables used by the query. Thus, for example,
a query would not be guaranteed to see updates committed by a
preceding transaction even if that transaction had exclusive lock.
We'll probably revisit this in future releases, but meanwhile put it
back the way it was before 9.2.
</para>
</listitem>
<listitem>
<para>
Acquire buffer lock when re-fetching the old tuple for an
<literal>AFTER ROW UPDATE/DELETE</> trigger (Andres Freund)
</para>
<para>
In very unusual circumstances, this oversight could result in passing
incorrect data to a trigger <literal>WHEN</> condition, or to the
precheck logic for a foreign-key enforcement trigger. That could
result in a crash, or in an incorrect decision about whether to
fire the trigger.
</para>
</listitem>
<listitem>
<para>
Fix <command>ALTER COLUMN TYPE</> to handle inherited check
constraints properly (Pavan Deolasee)
</para>
<para>
This worked correctly in pre-8.4 releases, and now works correctly
in 8.4 and later.
</para>
</listitem>
<listitem> <para>
Fix <command>ALTER EXTENSION SET SCHEMA</>'s failure to move some
subsidiary objects into the new schema (Álvaro Herrera, Dimitri
Fontaine)
</para>
</listitem>
<listitem>
<para>
Handle <command>CREATE TABLE AS EXECUTE</> correctly in extended query
protocol (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Don't modify the input parse tree in <command>DROP RULE IF NOT
EXISTS</> and <command>DROP TRIGGER IF NOT EXISTS</> (Tom Lane)
</para>
<para>
This mistake would cause errors if a cached statement of one of these
types was re-executed.
</para>
</listitem>
<listitem>
<para>
Fix <command>REASSIGN OWNED</> to handle grants on tablespaces
(Álvaro Herrera)
</para>
</listitem>
<listitem>
<para>
Ignore incorrect <structname>pg_attribute</> entries for system
columns for views (Tom Lane)
</para>
<para>
Views do not have any system columns. However, we forgot to
remove such entries when converting a table to a view. That's fixed
properly for 9.3 and later, but in previous branches we need to defend
against existing mis-converted views.
</para>
</listitem>
<listitem>
<para>
Fix rule printing to dump <literal>INSERT INTO <replaceable>table</>
DEFAULT VALUES</literal> correctly (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Guard against stack overflow when there are too many
<literal>UNION</>/<literal>INTERSECT</>/<literal>EXCEPT</> clauses
in a query (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Prevent platform-dependent failures when dividing the minimum possible
integer value by -1 (Xi Wang, Tom Lane)
</para>
</listitem>
<listitem> <para>
Fix possible access past end of string in date parsing
(Hitoshi Harada)
</para>
</listitem>
<listitem>
<para>
Fix failure to advance XID epoch if XID wraparound happens during a
checkpoint and <varname>wal_level</> is <literal>hot_standby</>
(Tom Lane, Andres Freund)
</para>
<para>
While this mistake had no particular impact on
<productname>PostgreSQL</productname> itself, it was bad for
applications that rely on <function>txid_current()</> and related
functions: the TXID value would appear to go backwards.
</para>
</listitem>
<listitem>
<para>
Fix <function>pg_terminate_backend()</> and
<function>pg_cancel_backend()</> to not throw error for a non-existent
target process (Josh Kupershmidt)
</para>
<para>
This case already worked as intended when called by a superuser,
but not so much when called by ordinary users.
</para>
</listitem>
<listitem>
<para>
Fix display of
<structname>pg_stat_replication</>.<structfield>sync_state</> at a
page boundary (Kyotaro Horiguchi)
</para>
</listitem>
<listitem>
<para>
Produce an understandable error message if the length of the path name
for a Unix-domain socket exceeds the platform-specific limit
(Tom Lane, Andrew Dunstan)
</para>
<para>
Formerly, this would result in something quite unhelpful, such as
<quote>Non-recoverable failure in name resolution</>.
</para>
</listitem>
<listitem>
<para>
Fix memory leaks when sending composite column values to the client
(Tom Lane)
</para>
</listitem>
<listitem>
<para>
Save some cycles by not searching for subtransaction locks at commit
(Simon Riggs)
</para>
<para>
In a transaction holding many exclusive locks, this useless activity could be quite costly.
</para>
</listitem>
<listitem>
<para>
Make <application>pg_ctl</> more robust about reading the
<filename>postmaster.pid</> file (Heikki Linnakangas)
</para>
<para>
This fixes race conditions and possible file descriptor leakage.
</para>
</listitem>
<listitem>
<para>
Fix possible crash in <application>psql</> if incorrectly-encoded data
is presented and the <varname>client_encoding</> setting is a
client-only encoding, such as SJIS (Jiang Guiqing)
</para>
</listitem>
<listitem>
<para>
Make <application>pg_dump</> dump <literal>SEQUENCE SET</> items in
the data not pre-data section of the archive (Tom Lane)
</para>
<para>
This fixes an undesirable inconsistency between the meanings of
<option>--data-only</> and <option>--section=data</>, and also fixes
dumping of sequences that are marked as extension configuration tables.
</para>
</listitem>
<listitem>
<para>
Fix <application>pg_dump</>'s handling of <command>DROP DATABASE</>
commands in <option>--clean</> mode (Guillaume Lelarge)
</para>
<para>
Beginning in 9.2.0, <literal>pg_dump --clean</> would issue a
<command>DROP DATABASE</> command, which was either useless or
dangerous depending on the usage scenario. It no longer does that.
This change also fixes the combination of <option>--clean</> and
<option>--create</> to work sensibly, i.e., emit <command>DROP
DATABASE</> then <command>CREATE DATABASE</> before reconnecting to the
target database.
</para>
</listitem>
<listitem>
<para>
Fix <application>pg_dump</> for views with circular dependencies and
no relation options (Tom Lane)
</para>
<para>
The previous fix to dump relation options when a view is
involved in a circular dependency didn't work right for the case
that the view has no options; it emitted <literal>ALTER VIEW foo
SET ()</> which is invalid syntax.
</para>
</listitem>
<listitem>
<para>
Fix bugs in the <filename>restore.sql</> script emitted by <application>pg_dump</> in <literal>tar</> output format (Tom Lane)
</para>
<para>
The script would fail outright on tables whose names include
upper-case characters. Also, make the script capable of restoring
data in <option>--inserts</> mode as well as the regular COPY mode.
</para>
</listitem>
<listitem>
<para>
Fix <application>pg_restore</> to accept POSIX-conformant
<literal>tar</> files (Brian Weaver, Tom Lane)
</para>
<para>
The original coding of <application>pg_dump</>'s <literal>tar</>
output mode produced files that are not fully conformant with the
POSIX standard. This has been corrected for version 9.3. This
patch updates previous branches so that they will accept both the
incorrect and the corrected formats, in hopes of avoiding
compatibility problems when 9.3 comes out.
</para>
</listitem>
<listitem>
<para>
Fix <literal>tar</> files emitted by <application>pg_basebackup</> to
be POSIX conformant (Brian Weaver, Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix <application>pg_resetxlog</> to locate <filename>postmaster.pid</>
correctly when given a relative path to the data directory (Tom Lane)
</para>
<para>
This mistake could lead to <application>pg_resetxlog</> not noticing
that there is an active postmaster using the data directory.
</para>
</listitem>
<listitem>
<para>
Fix <application>libpq</>'s <function>lo_import()</> and
<function>lo_export()</> functions to report file I/O errors properly
(Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix <application>ecpg</>'s processing of nested structure pointer
variables (Muhammad Usama)
</para>
</listitem>
<listitem>
<para>
Fix <application>ecpg</>'s <function>ecpg_get_data</> function to
handle arrays properly (Michael Meskes)
</para>
</listitem>
<listitem>
<para>
Prevent <application>pg_upgrade</> from trying to process TOAST tables for system catalogs (Bruce Momjian)
</para>
<para>
This fixes an error seen when the <literal>information_schema</> has
been dropped and recreated. Other failures were also possible.
</para>
</listitem>
<listitem>
<para>
Improve <application>pg_upgrade</> performance by setting
<varname>synchronous_commit</> to <literal>off</> in the new cluster
(Bruce Momjian)
</para>
</listitem>
<listitem>
<para>
Make <filename>contrib/pageinspect</>'s btree page inspection
functions take buffer locks while examining pages (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Work around unportable behavior of <literal>malloc(0)</> and
<literal>realloc(NULL, 0)</> (Tom Lane)
</para>
<para>
On platforms where these calls return <literal>NULL</>, some code
mistakenly thought that meant out-of-memory.
This is known to have broken <application>pg_dump</> for databases
containing no user-defined aggregates. There might be other cases
as well.
</para>
</listitem>
<listitem>
<para>
Ensure that <literal>make install</> for an extension creates the
<filename>extension</> installation directory (Cédric Villemain)
</para>
<para>
Previously, this step was missed if <varname>MODULEDIR</> was set in
the extension's Makefile.
</para>
</listitem>
<listitem>
<para>
Fix <application>pgxs</> support for building loadable modules on AIX
(Tom Lane)
</para>
<para>
Building modules outside the original source tree didn't work on AIX.
</para>
</listitem>
<listitem>
<para>
Update time zone data files to <application>tzdata</> release 2012j
for DST law changes in Cuba, Israel, Jordan, Libya, Palestine, Western
Samoa, and portions of Brazil.
</para>
</listitem>
</itemizedlist>
</sect2>
</sect1>
<sect1 id="release-9-2-1">
<title>Release 9.2.1</title>
<note>
<title>Release Date</title>
<simpara>2012-09-24</simpara>
</note>
<para>
This release contains a variety of fixes from 9.2.0.
For information about new features in the 9.2 major release, see
<xref linkend="release-9-2">.
</para>
<sect2>
<title>Migration to Version 9.2.1</title>
<para>
A dump/restore is not required for those running 9.2.X.
</para>
<para>
However, you may need to perform <command>REINDEX</> and/or
<command>VACUUM</> operations to recover from the effects of the data
corruption bug described in the first changelog item below.
</para>
</sect2>
<sect2>
<title>Changes</title>
<itemizedlist>
<listitem>
<para>
Fix persistence marking of shared buffers during WAL replay
(Jeff Davis)
</para>
<para>
This mistake can result in buffers not being written out during
checkpoints, resulting in data corruption if the server later crashes
without ever having written those buffers. Corruption can occur on
any server following crash recovery, but it is significantly more
likely to occur on standby slave servers since those perform much
more WAL replay. There is a low probability of corruption of btree
and GIN indexes. There is a much higher probability of corruption
of table <quote>visibility maps</>, which might lead to wrong answers
from index-only scans. Table data proper cannot be corrupted by this
bug.
</para>
<para>
While no index corruption due to this bug is known to have occurred
in the field, as a precautionary measure it is recommended that
production installations <command>REINDEX</> all btree and GIN
indexes at a convenient time after upgrading to 9.2.1.
</para>
<para>
Also, it is recommended to perform a <command>VACUUM</> of all tables
while having <link
linkend="guc-vacuum-freeze-table-age"><varname>vacuum_freeze_table_age</></link>
set to zero. This will fix any incorrect visibility map data. <link linkend="guc-vacuum-cost-delay"><varname>vacuum_cost_delay</></link>
can be adjusted to reduce the performance impact of vacuuming, while
causing it to take longer to finish.
</para>
</listitem>
<listitem>
<para>
Fix possible incorrect sorting of output from queries involving
<literal>WHERE <replaceable>indexed_column</> IN
(<replaceable>list_of_values</>)</literal> (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix planner failure for queries involving <literal>GROUP BY</>
expressions along with window functions and aggregates (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix planner's assignment of executor parameters (Tom Lane)
</para>
<para>
This error could result in wrong answers from queries that scan the
same <literal>WITH</> subquery multiple times.
</para>
</listitem>
<listitem>
<para>
Improve planner's handling of join conditions in index scans (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Improve selectivity estimation for text search queries involving
prefixes, i.e. <replaceable>word</><literal>:*</> patterns (Tom Lane)
</para>
<para>
</para>
</listitem>
<listitem>
<para>
Fix delayed recognition of permissions changes (Tom Lane)
</para>
<para>
A command that needed no locks other than ones its transaction already
had might fail to notice a concurrent <command>GRANT</> or
<command>REVOKE</> that committed since the start of its transaction.
</para>
</listitem>
<listitem>
<para>
Fix <command>ANALYZE</> to not fail when a column is a domain over an
array type (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Prevent PL/Perl from crashing if a recursive PL/Perl function is redefined while being executed (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Work around possible misoptimization in PL/Perl (Tom Lane)
</para>
<para>
Some Linux distributions contain an incorrect version of
<filename>pthread.h</> that results in incorrect compiled code in
PL/Perl, leading to crashes if a PL/Perl function calls another one
that throws an error.
</para>
</listitem>
<listitem>
<para>
Remove unnecessary dependency on <application>pg_config</> from
<application>pg_upgrade</> (Peter Eisentraut)
</para>
</listitem>
<listitem>
<para>
Update time zone data files to <application>tzdata</> release 2012f
for DST law changes in Fiji
</para>
</listitem>
</itemizedlist>
</sect2>
</sect1>
<sect1 id="release-9-2">
<title>Release 9.2</title>
<note>
<title>Release Date</title>
<simpara>2012-09-10</simpara>
</note>
<sect2>
<title>Overview</title>
<para>
This release has been largely focused on performance improvements, though
new SQL features are not lacking. Work also continues in the area of
replication support. Major enhancements include:
</para>
<itemizedlist>
<!-- This list duplicates items below, but without authors or details-->
<listitem>
<para>
Allow queries to retrieve data only from indexes, avoiding heap
access (<firstterm>index-only scans</>)
</para>
</listitem>
<listitem>
<para>
Allow the planner to generate custom plans for specific parameter
values even when using prepared statements
</para>
</listitem>
<listitem>
<para>
Improve the planner's ability to use nested loops with inner
index scans
</para>
</listitem>
<listitem>
<para>
Allow streaming replication slaves to forward data to other slaves
(<link linkend="cascading-replication"><firstterm>cascading
replication</></link>)
</para>
</listitem>
<listitem>
<para>
Allow <link
linkend="app-pgbasebackup"><application>pg_basebackup</></link>
to make base backups from standby servers
</para>
</listitem>
<listitem>
<para>
Add a <link
linkend="app-pgreceivexlog"><application>pg_receivexlog</></link>
tool to archive WAL file changes as they are written
</para>
</listitem>
<listitem>
<para>
Add the <link linkend="SPGiST">SP-GiST</link> (Space-Partitioned
GiST) index access method
</para>
</listitem>
<listitem>
<para>
Add support for <link linkend="rangetypes">range data types</link>
</para>
</listitem>
<listitem>
<para>
Add a <link linkend="datatype-json"><type>JSON</type></link>
data type
</para>
</listitem>
<listitem>
<para>
Add a <link
linkend="SQL-CREATEVIEW"><literal>security_barrier</></link>
option for views
</para>
</listitem>
<listitem>
<para>
Allow <application>libpq</> connection strings to have the format of a
<link linkend="libpq-connstring"><acronym>URI</acronym></link>
</para>
</listitem>
<listitem>
<para>
Add a <link linkend="libpq-single-row-mode">single-row processing mode</link> to <application>libpq</> for better handling of large
result sets
</para>
</listitem>
</itemizedlist>
<para>
The above items are explained in more detail in the sections below.
</para>
</sect2>
<sect2>
<title>Migration to Version 9.2</title>
<para>
A dump/restore using <application>pg_dump</application>, or use of
<application>pg_upgrade</application>, is required for those wishing
to migrate data from any previous release.
</para>
<para>
Version 9.2 contains a number of changes that may affect compatibility
with previous releases. Observe the following incompatibilities:
</para>
<sect3>
<title>System Catalogs</title>
<itemizedlist>
<listitem>
<para>
Remove the <structfield>spclocation</> field from <link
linkend="catalog-pg-tablespace"><structname>pg_tablespace</></link>
(Magnus Hagander)
</para>
<para>
This field was duplicative of the symbolic links that actually define
tablespace locations, and thus risked errors of omission when moving
a tablespace. This change allows tablespace directories to be moved
while the server is down, by manually adjusting the symbolic links.
To replace this field, we have added <link
linkend="functions-info-catalog-table"><function>pg_tablespace_location()</></link>
to allow querying of the symbolic links.
</para>
</listitem>
<listitem>
<para>
Move <type>tsvector</> most-common-element statistics to new
<link linkend="view-pg-stats"><structname>pg_stats</></link> columns
(Alexander Korotkov)
</para>
<para>
Consult <structfield>most_common_elems</>
and <structfield>most_common_elem_freqs</> for the data formerly
available in <structfield>most_common_vals</>
and <structfield>most_common_freqs</> for a <type>tsvector</> column.
</para>
</listitem>
</itemizedlist>
</sect3>
<sect3>
<title>Functions</title>
<itemizedlist>
<listitem>
<para>
Remove <link linkend="hstore">hstore</link>'s <literal>=></>
operator (Robert Haas)
</para>
<para>
Users should now use <function>hstore(text, text)</>. Since
<productname>PostgreSQL</productname> 9.0, a warning message has been
emitted when an operator named <literal>=></> is created because
the <acronym>SQL</acronym> standard reserves that token for
another use.
</para>
</listitem>
<listitem>
<para>
Ensure that <link
linkend="functions-xml-processing"><function>xpath()</></link>
escapes special characters in string values (Florian Pflug)
</para>
<para>
Without this it is possible for the result not to be valid
<acronym>XML</acronym>.
</para>
</listitem>
<listitem>
<para>
Make <link
linkend="functions-admin-dbobject"><function>pg_relation_size()</></link>
and friends return NULL if the object does not exist (Phil Sorber)
</para>
<para>
This prevents queries that call these functions from returning
errors immediately after a concurrent <command>DROP</>.
</para>
</listitem>
<listitem>
<para>
Make <link
linkend="functions-datetime-extract"><function>EXTRACT(EPOCH FROM
<replaceable>timestamp without time zone</>)</function></link>
measure the epoch from local midnight, not <acronym>UTC</acronym>
midnight (Tom Lane)
</para>
<para>
This change reverts an ill-considered change made in release 7.3.
Measuring from <acronym>UTC</acronym> midnight was inconsistent
because it made the result dependent on the <link
linkend="guc-timezone"><varname>timezone</></link> setting, which
computations for <type>timestamp without time zone</> should not be.
The previous behavior remains available by casting the input value
to <type>timestamp with time zone</>.
</para>
</listitem>
<listitem>
<para>
Properly parse time strings with trailing <literal>yesterday</>,
<literal>today</>, and <literal>tomorrow</> (Dean Rasheed) </para>
<para>
Previously, <literal>SELECT '04:00:00 yesterday'::timestamp</literal>
returned yesterday's date at midnight.
</para>
</listitem>
<listitem>
<para>
Fix <link
linkend="functions-formatting"><function>to_date()</></link> and
<function>to_timestamp()</> to wrap incomplete dates toward 2020
(Bruce Momjian)
</para>
<para>
Previously, supplied years and year masks of less than four digits
wrapped inconsistently.
</para>
</listitem>
</itemizedlist>
</sect3>
<sect3>
<title>Object Modification</title>
<itemizedlist>
<listitem>
<para>
Prevent <link linkend="SQL-ALTERDOMAIN"><command>ALTER
DOMAIN</command></link> from working on non-domain types (Peter
Eisentraut)
</para>
<para>
Owner and schema changes were previously possible on non-domain
types.
</para>
</listitem>
<listitem>
<para>
No longer forcibly lowercase procedural language names in <link
linkend="SQL-CREATEFUNCTION"><command>CREATE FUNCTION</></link>
(Robert Haas)
</para>
<para>
While unquoted language identifiers are still lowercased, strings
and quoted identifiers are no longer forcibly down-cased.
Thus for example <literal>CREATE FUNCTION ... LANGUAGE 'C'</>
will no longer work; it must be spelled <literal>'c'</>, or better
omit the quotes.
</para>
</listitem>
<listitem>
<para>
Change system-generated names of foreign key enforcement triggers
(Tom Lane)
</para>
<para>
This change ensures that the triggers fire in the correct order in
some corner cases involving self-referential foreign key constraints.
</para> </listitem>
</itemizedlist>
</sect3>
<sect3>
<title>Command-Line Tools</title>
<itemizedlist>
<listitem>
<para>
Provide consistent backquote, variable
expansion, and quoted substring behavior in <link
linkend="APP-PSQL"><application>psql</></link> meta-command
arguments (Tom Lane)
</para>
<para>
Previously, such references were treated oddly when not separated by
whitespace from adjacent text. For example <literal>'FOO'BAR</> was
output as <literal>FOO BAR</> (unexpected insertion of a space) and
<literal>FOO'BAR'BAZ</> was output unchanged (not removing the quotes
as most would expect).
</para>
</listitem>
<listitem>
<para>
No longer treat <link
linkend="APP-CLUSTERDB"><application>clusterdb</></link>
table names as double-quoted; no longer treat <link
linkend="APP-REINDEXDB"><application>reindexdb</></link> table
and index names as double-quoted (Bruce Momjian)
</para>
<para>
Users must now include double-quotes in the command arguments if
quoting is wanted.
</para>
</listitem>
<listitem>
<para>
<link linkend="APP-CREATEUSER"><application>createuser</></link>
no longer prompts for option settings by default (Peter Eisentraut)
</para>
<para>
Use <option>--interactive</> to obtain the old behavior.
</para>
</listitem>
<listitem>
<para>
Disable prompting for the user name in <link
linkend="APP-DROPUSER"><application>dropuser</></link> unless
<option>--interactive</> is specified (Peter Eisentraut)
</para>
</listitem>
</itemizedlist>
</sect3>
<sect3>
<title>Server Settings</title>
<itemizedlist>
<listitem>
<para>
Add server parameters for specifying the <link
linkend="guc-ssl-ca-file">locations of server-side
<acronym>SSL</acronym> files</link> (Peter Eisentraut)
</para>
<para>
This allows changing the names and locations of the files that were
previously hard-coded as <filename>server.crt</>,
<filename>server.key</>, <filename>root.crt</>, and
<filename>root.crl</> in the data directory.
<emphasis>The server will no longer examine <filename>root.crt</> or
<filename>root.crl</> by default</emphasis>; to load these files, the
associated parameters must be set to non-default values.
</para>
</listitem>
<listitem>
<para>
Remove the <varname>silent_mode</> parameter (Heikki Linnakangas)
</para>
<para>
Similar behavior can be obtained with <command>pg_ctl start
-l postmaster.log</>.
</para>
</listitem>
<listitem>
<para>
Remove the <varname>wal_sender_delay</> parameter,
as it is no longer needed (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Remove the <varname>custom_variable_classes</> parameter (Tom Lane)
</para>
<para>
The checking provided by this setting was dubious. Now any
setting can be prefixed by any class name.
</para>
</listitem>
</itemizedlist>
</sect3>
<sect3>
<title>Monitoring</title>
<itemizedlist>
<listitem>
<para>
Rename <link
linkend="monitoring-stats-views-table"><structname>pg_stat_activity</></link><structfield>.procpid</>
to <structfield>pid</>, to match other system tables (Magnus Hagander)
</para>
</listitem>
<listitem>
<para>
Create a separate <structfield>pg_stat_activity</> column to
report process state (Scott Mead, Magnus Hagander)
</para>
<para>
The previous <structfield>query</> and <structfield>query_start</>
values now remain available for an idle session, allowing enhanced
analysis.
</para>
</listitem>
<listitem>
<para>
Rename <structname>pg_stat_activity</>.<structfield>current_query</> to
<structfield>query</> because it is not cleared when the query
completes (Magnus Hagander)
</para>
</listitem>
<listitem>
<para>
Change all <acronym>SQL</acronym>-level statistics timing values
to be <type>float8</> columns measured in milliseconds (Tom Lane)
</para>
<para>
This change eliminates the designed-in assumption that the values
are accurate to microseconds and no more (since the <type>float8</>
values can be fractional).
The columns affected are
<structname>pg_stat_user_functions</>.<structfield>total_time</>,
<structname>pg_stat_user_functions</>.<structfield>self_time</>,
<structname>pg_stat_xact_user_functions</>.<structfield>total_time</>,
and
<structname>pg_stat_xact_user_functions</>.<structfield>self_time</>.
The statistics functions underlying these columns now also return
<type>float8</> milliseconds, rather than <type>bigint</>
microseconds.
<filename>contrib/pg_stat_statements</>'
<structfield>total_time</> column is now also measured in
milliseconds.
</para>
</listitem>
</itemizedlist>
</sect3>
</sect2>
<sect2>
<title>Changes</title>
<para>
Below you will find a detailed account of the changes between
<productname>PostgreSQL</productname> 9.2 and the previous major
release.
</para>
<sect3>
<title>Server</title>
<sect4>
<title>Performance</title>
<itemizedlist>
<listitem>
<para>
Allow queries to retrieve data only from indexes, avoiding heap
access (Robert Haas, Ibrar Ahmed, Heikki Linnakangas, Tom Lane)
</para>
<para>
This feature is often called <firstterm>index-only scans</>. Heap access can be skipped for heap pages containing only tuples that
are visible to all sessions, as reported by the visibility map; so
the benefit applies mainly to mostly-static data. The visibility map
was made crash-safe as a necessary part of implementing this feature.
</para>
</listitem>
<listitem>
<para>
Add the <link linkend="SPGiST">SP-GiST</link> (Space-Partitioned
GiST) index access method (Teodor Sigaev, Oleg Bartunov, Tom
Lane)
</para>
<para>
SP-GiST is comparable to GiST in flexibility, but supports
unbalanced partitioned search structures rather than balanced
trees. For suitable problems, SP-GiST can be faster than GiST in both
index build time and search time.
</para>
</listitem>
<listitem>
<para>
Allow group commit to work effectively under heavy load (Peter
Geoghegan, Simon Riggs, Heikki Linnakangas)
</para>
<para>
Previously, batching of commits became ineffective as the write
workload increased, because of internal lock contention.
</para>
</listitem>
<listitem>
<para>
Allow uncontended locks to be managed using a new
fast-path lock mechanism (Robert Haas)
</para>
</listitem>
<listitem>
<para>
Reduce overhead of creating virtual transaction ID locks (Robert
Haas)
</para>
</listitem>
<listitem>
<para>
Reduce the overhead of serializable isolation level locks (Dan
Ports)
</para>
</listitem>
<listitem>
<para>
Improve PowerPC and Itanium spinlock performance (Manabu Ori,
Robert Haas, Tom Lane)
</para>
</listitem>
<listitem>
<para>
Reduce overhead for shared invalidation cache messages (Robert
Haas)
</para>
</listitem>
<listitem> <para>
Move the frequently accessed members of the <structname>PGPROC</>
shared memory array to a separate array (Pavan
Deolasee, Heikki Linnakangas, Robert Haas)
</para>
</listitem>
<listitem>
<para>
Improve <command>COPY</command> performance by adding tuples to
the heap in batches (Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Improve GiST index performance for geometric data types by producing
better trees with less memory allocation overhead (Alexander Korotkov)
</para>
</listitem>
<listitem>
<para>
Improve GiST index build times (Alexander Korotkov, Heikki
Linnakangas)
</para>
</listitem>
<listitem>
<para>
Allow hint bits to be set sooner for temporary and unlogged tables
(Robert Haas)
</para>
</listitem>
<listitem>
<para>
Allow sorting to be performed by inlined,
non-<acronym>SQL</acronym>-callable comparison functions (Peter
Geoghegan, Robert Haas, Tom Lane)
</para>
</listitem>
<listitem>
<para>
Make the number of CLOG buffers scale based on <link
linkend="guc-shared-buffers"><varname>shared_buffers</></link>
(Robert Haas, Simon Riggs, Tom Lane)
</para>
</listitem>
<listitem>
<para>
Improve performance of buffer pool scans that occur when tables or
databases are dropped (Jeff Janes, Simon Riggs)
</para>
</listitem>
<listitem>
<para>
Improve performance of checkpointer's fsync-request queue
when many tables are being dropped or truncated (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Pass the safe number of file descriptors to child processes on Windows
(Heikki Linnakangas)
</para>
<para>
This allows Windows sessions to use more open file descriptors than
before.
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title>Process Management</title>
<itemizedlist>
<listitem>
<para>
Create a dedicated background process to perform checkpoints (Simon
Riggs)
</para>
<para>
Formerly the background writer did both dirty-page writing and
checkpointing. Separating this into two processes allows each goal
to be accomplished more predictably.
</para>
</listitem>
<listitem>
<para>
Improve asynchronous commit behavior by waking the walwriter sooner
(Simon Riggs)
</para>
<para>
Previously, only <link
linkend="guc-wal-writer-delay"><varname>wal_writer_delay</></link>
triggered <acronym>WAL</acronym> flushing to disk; now filling a
<acronym>WAL</acronym> buffer also triggers <acronym>WAL</acronym>
writes.
</para>
</listitem>
<listitem>
<para>
Allow the bgwriter, walwriter, checkpointer, statistics collector,
log collector, and archiver background processes to sleep more
efficiently during periods of inactivity (Peter Geoghegan, Tom Lane)
</para>
<para>
This series of changes reduces the frequency of process wake-ups when
there is nothing to do, dramatically reducing power consumption on
idle servers.
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title>Optimizer</title>
<itemizedlist>
<listitem>
<para>
Allow the planner to generate custom plans for specific parameter values even when using prepared statements
(Tom Lane)
</para>
<para>
In the past, a prepared statement always had a single
<quote>generic</> plan that was used for all parameter values, which
was frequently much inferior to the plans used for non-prepared
statements containing explicit constant values. Now, the planner
attempts to generate custom plans for specific parameter values.
A generic plan will only be used after custom plans have repeatedly
proven to provide no benefit. This change should eliminate the
performance penalties formerly seen from use of prepared statements
(including non-dynamic statements in PL/pgSQL).
</para>
</listitem>
<listitem>
<para>
Improve the planner's ability to use nested loops with inner
index scans (Tom Lane)
</para>
<para>
The new <quote>parameterized path</> mechanism allows inner
index scans to use values from relations that are more than one join
level up from the scan. This can greatly improve performance in
situations where semantic restrictions (such as outer joins) limit
the allowed join orderings.
</para>
</listitem>
<listitem>
<para>
Improve the planning <acronym>API</acronym> for foreign data wrappers
(Etsuro Fujita, Shigeru Hanada, Tom Lane)
</para>
<para>
Wrappers can now provide multiple access <quote>paths</> for their
tables, allowing more flexibility in join planning.
</para>
</listitem>
<listitem>
<para>
Recognize self-contradictory restriction clauses for non-table
relations (Tom Lane)
</para>
<para>
This check is only performed when <link
linkend="guc-constraint-exclusion"><varname>constraint_exclusion</></link>
is <literal>on</literal>.
</para>
</listitem>
<listitem>
<para>
Allow <literal>indexed_col op ANY(ARRAY[...])</> conditions to be
used in plain index scans and index-only scans (Tom Lane)
</para>
<para>
Formerly such conditions could only be used in bitmap index scans.
</para>
</listitem>
<listitem>
<para> Support <function>MIN</>/<function>MAX</> index optimizations on
<type>boolean</type> columns (Marti Raudsepp)
</para>
</listitem>
<listitem>
<para>
Account for set-returning functions in <command>SELECT</> target
lists when setting row count estimates (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix planner to handle indexes with duplicated columns more reliably
(Tom Lane)
</para>
</listitem>
<listitem>
<para>
Collect and use element-frequency statistics for arrays (Alexander
Korotkov, Tom Lane)
</para>
<para>
This change improves selectivity estimation for the array
<literal><@</literal>, <literal>&&</literal>, and
<literal>@></literal> operators (array containment and overlaps).
</para>
</listitem>
<listitem>
<para>
Allow statistics to be collected for foreign tables
(Etsuro Fujita)
</para>
</listitem>
<listitem>
<para>
Improve cost estimates for use of partial indexes (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Improve the planner's ability to use statistics for columns
referenced in subqueries (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Improve statistical estimates for subqueries using
<literal>DISTINCT</> (Tom Lane)
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title>Authentication</title>
<itemizedlist>
<listitem>
<para> Do not treat role names and <literal>samerole</> specified in <link
linkend="auth-pg-hba-conf"><filename>pg_hba.conf</filename></link>
as automatically including superusers (Andrew Dunstan)
</para>
<para>
This makes it easier to use <literal>reject</> lines with group roles.
</para>
</listitem>
<listitem>
<para>
Adjust <filename>pg_hba.conf</filename> processing to handle token
parsing more consistently (Brendan Jurd, Álvaro Herrera)
</para>
</listitem>
<listitem>
<para>
Disallow empty <filename>pg_hba.conf</filename> files (Tom Lane)
</para>
<para>
This was done to more quickly detect misconfiguration.
</para>
</listitem>
<listitem>
<para>
Make superuser privilege imply replication privilege (Noah Misch)
</para>
<para>
This avoids the need to explicitly assign such privileges.
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title>Monitoring</title>
<itemizedlist>
<listitem>
<para>
Attempt to log the current query string during a backend crash
(Marti Raudsepp)
</para>
</listitem>
<listitem>
<para>
Make logging of autovacuum I/O activity more verbose (Greg
Smith, Noah Misch)
</para>
<para>
This logging is triggered by <link
linkend="guc-log-autovacuum-min-duration"><varname>log_autovacuum_min_duration</></link>.
</para>
</listitem>
<listitem>
<para>
Make <acronym>WAL</acronym> replay report failures sooner
(Fujii Masao)
</para>
<para>
There were some cases where failures were only reported once the
server went into master mode.
</para>
</listitem>
<listitem>
<para>
Add <link
linkend="functions-admin-backup"><function>pg_xlog_location_diff()</></link>
to simplify WAL location comparisons (Euler Taveira de Oliveira)
</para>
<para>
This is useful for computing replication lag.
</para>
</listitem>
<listitem>
<para>
Support configurable event log application names on Windows
(MauMau, Magnus Hagander)
</para>
<para>
This allows different instances to use the event log
with different identifiers, by setting the <link
linkend="guc-event-source"><varname>event_source</></link>
server parameter, which is similar to how <link
linkend="guc-syslog-ident"><varname>syslog_ident</></link> works.
</para>
</listitem>
<listitem>
<para>
Change <quote>unexpected EOF</> messages to <literal>DEBUG1</> level,
except when there is an open transaction (Magnus Hagander)
</para>
<para>
This change reduces log chatter caused by applications that close
database connections ungracefully.
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title>Statistical Views</title>
<itemizedlist>
<listitem>
<para>
Track temporary file sizes and file counts in the <link
linkend="pg-stat-database-view"><structname>pg_stat_database</></link>
system view (Tomas Vondra)
</para>
</listitem>
<listitem>
<para>
Add a deadlock counter to the <structname>pg_stat_database</>
system view (Magnus Hagander)
</para>
</listitem>
<listitem>
<para>
Add a server parameter <link
linkend="guc-track-io-timing"><varname>track_io_timing</></link>
to track I/O timings (Ants Aasma, Robert Haas)
</para>
</listitem>
<listitem>
<para>
Report checkpoint timing information in <link
linkend="pg-stat-bgwriter-view"><structname>pg_stat_bgwriter</></link>
(Greg Smith, Peter Geoghegan)
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title>Server Settings</title>
<itemizedlist>
<listitem>
<para>
Silently ignore nonexistent schemas specified in <link
linkend="guc-search-path"><varname>search_path</></link> (Tom Lane)
</para>
<para>
This makes it more convenient to use generic path settings, which
might include some schemas that don't exist in all databases.
</para>
</listitem>
<listitem>
<para>
Allow superusers to set <link
linkend="guc-deadlock-timeout"><varname>deadlock_timeout</></link>
per-session, not just per-cluster (Noah Misch)
</para>
<para>
This allows <varname>deadlock_timeout</> to be reduced for
transactions that are likely to be involved in a deadlock, thus
detecting the failure more quickly. Alternatively, increasing the
value can be used to reduce the chances of a session being chosen for
cancellation due to a deadlock.
</para>
</listitem>
<listitem>
<para>
Add a server parameter <link
linkend="guc-temp-file-limit"><varname>temp_file_limit</></link>
to constrain temporary file space usage per session (Mark Kirkwood)
</para>
</listitem>
<listitem>
<para>
Allow a superuser to <command>SET</command> an extension's
superuser-only custom variable before loading the associated
extension (Tom Lane)
</para>
<para>
The system now remembers whether a <command>SET</command> was performed by a superuser, so that proper privilege checking can be
done when the extension is loaded.
</para>
</listitem>
<listitem>
<para>
Add <link linkend="app-postmaster">postmaster</link> <option>-C</>
option to query configuration parameters (Bruce Momjian)
</para>
<para>
This allows <application>pg_ctl</> to better handle cases where
<envar>PGDATA</> or <option>-D</> points to a configuration-only
directory.
</para>
</listitem>
<listitem>
<para>
Replace an empty locale name with the implied value in
<command>CREATE DATABASE</>
(Tom Lane)
</para>
<para>
This prevents cases where
<structname>pg_database</>.<structfield>datcollate</> or
<structfield>datctype</> could be interpreted differently after a
server restart.
</para>
</listitem>
</itemizedlist>
<sect5>
<title><filename>postgresql.conf</filename></title>
<itemizedlist>
<listitem>
<para>
Allow multiple errors in <filename>postgresql.conf</filename>
to be reported, rather than just the first one (Alexey Klyukin,
Tom Lane)
</para>
</listitem>
<listitem>
<para>
Allow a reload of <filename>postgresql.conf</filename> to be
processed by all sessions, even if there are some settings that
are invalid for particular sessions (Alexey Klyukin)
</para>
<para>
Previously, such not-valid-within-session values would cause all
setting changes to be ignored by that session.
</para>
</listitem>
<listitem>
<para>
Add an <literal>include_if_exists</> facility for configuration
files (Greg Smith)
</para>
<para>
This works the same as <literal>include</>, except that an error
is not thrown if the file is missing. </para>
</listitem>
<listitem>
<para>
Identify the server time zone during <application>initdb</>, and set
<filename>postgresql.conf</filename> entries
<link linkend="guc-timezone"><varname>timezone</></link> and
<link linkend="guc-log-timezone"><varname>log_timezone</></link>
accordingly (Tom Lane)
</para>
<para>
This avoids expensive time zone probes during server start.
</para>
</listitem>
<listitem>
<para>
Fix <link
linkend="view-pg-settings"><structname>pg_settings</></link> to
report <filename>postgresql.conf</filename> line numbers on Windows
(Tom Lane)
</para>
</listitem>
</itemizedlist>
</sect5>
</sect4>
</sect3>
<sect3>
<title>Replication and Recovery</title>
<itemizedlist>
<listitem>
<para>
Allow streaming replication slaves to forward data to other slaves
(<link linkend="cascading-replication"><firstterm>cascading
replication</></link>) (Fujii Masao)
</para>
<para>
Previously, only the master server could supply streaming
replication log files to standby servers.
</para>
</listitem>
<listitem>
<para>
Add new <link
linkend="guc-synchronous-commit"><varname>synchronous_commit</></link>
mode <literal>remote_write</> (Fujii Masao, Simon Riggs)
</para>
<para>
This mode waits for the standby server to write transaction data to
its own operating system, but does not wait for the data to be
flushed to the standby's disk.
</para>
</listitem>
<listitem>
<para>
Add a <link
linkend="app-pgreceivexlog"><application>pg_receivexlog</></link> tool to archive WAL file changes as they are written, rather
than waiting for completed WAL files (Magnus Hagander)
</para>
</listitem>
<listitem>
<para>
Allow <link
linkend="app-pgbasebackup"><application>pg_basebackup</></link>
to make base backups from standby servers (Jun Ishizuka, Fujii Masao)
</para>
<para>
This feature lets the work of making new base backups be off-loaded
from the primary server.
</para>
</listitem>
<listitem>
<para>
Allow streaming of WAL files while <application>pg_basebackup</>
is performing a backup (Magnus Hagander)
</para>
<para>
This allows passing of WAL files to the standby before they are
discarded on the primary.
</para>
</listitem>
</itemizedlist>
</sect3>
<sect3>
<title>Queries</title>
<itemizedlist>
<listitem>
<para>
Cancel the running query if the client gets disconnected
(Florian Pflug)
</para>
<para>
If the backend detects loss of client connection during a query, it
will now cancel the query rather than attempting to finish it.
</para>
</listitem>
<listitem>
<para>
Retain column names at run time for row expressions
(Andrew Dunstan, Tom Lane)
</para>
<para>
This change allows better results when a row value is converted to
<type>hstore</> or <type>json</> type: the fields of the resulting
value will now have the expected names.
</para>
</listitem>
<listitem>
<para>
Improve column labels used for sub-<command>SELECT</> results
(Marti Raudsepp)
</para>
<para>
Previously, the generic label <literal>?column?</> was used.
</para>
</listitem>
<listitem>
<para>
Improve heuristics for determining the types of unknown values
(Tom Lane)
</para>
<para>
The longstanding rule that an unknown constant might have the
same type as the value on the other side of the operator using it
is now applied when considering polymorphic operators, not only
for simple operator matches.
</para>
</listitem>
<listitem>
<para>
Warn about creating casts to or from domain types (Robert Haas)
</para>
<para>
Such casts have no effect.
</para>
</listitem>
<listitem>
<para>
When a row fails a <literal>CHECK</> or <literal>NOT NULL</>
constraint, show the row's contents as error detail (Jan
Kundrát)
</para>
<para>
This should make it easier to identify which row is problematic
when an insert or update is processing many rows.
</para>
</listitem>
</itemizedlist>
</sect3>
<sect3>
<title>Object Manipulation</title>
<itemizedlist>
<listitem>
<para>
Provide more reliable operation during concurrent
<acronym>DDL</acronym> (Robert Haas, Noah Misch)
</para>
<para>
This change adds locking that should eliminate <quote>cache lookup
failed</> errors in many scenarios. Also, it is no longer possible
to add relations to a schema that is being concurrently dropped, a
scenario that formerly led to inconsistent system catalog contents.
</para>
</listitem>
<listitem>
<para>
Add <literal>CONCURRENTLY</> option to <link
linkend="SQL-DROPINDEX"><command>DROP INDEX</command></link>
(Simon Riggs) </para>
<para>
This allows index removal without blocking other sessions.
</para>
</listitem>
<listitem>
<para>
Allow foreign data wrappers to have per-column options (Shigeru Hanada)
</para>
</listitem>
<listitem>
<para>
Improve pretty-printing of view definitions (Andrew Dunstan)
</para>
</listitem>
</itemizedlist>
<sect4>
<title>Constraints</title>
<itemizedlist>
<listitem>
<para>
Allow <link linkend="ddl-constraints"><literal>CHECK</></link>
constraints to be declared <literal>NOT VALID</> (Álvaro
Herrera)
</para>
<para>
Adding a <literal>NOT VALID</> constraint does not cause the table to
be scanned to verify that existing rows meet the constraint.
Subsequently, newly added or updated rows are checked.
Such constraints are ignored by the planner when considering
<varname>constraint_exclusion</>, since it is not certain that all
rows meet the constraint.
</para>
<para>
The new <command>ALTER TABLE VALIDATE</> command allows <literal>NOT
VALID</> constraints to be checked for existing rows, after which
they are converted into ordinary constraints.
</para>
</listitem>
<listitem>
<para>
Allow <literal>CHECK</> constraints to be declared <literal>NO
INHERIT</> (Nikhil Sontakke, Alex Hunsaker, Álvaro Herrera)
</para>
<para>
This makes them enforceable only on the parent table, not on
child tables.
</para>
</listitem>
<listitem>
<para>
Add the ability to <link linkend="SQL-ALTERTABLE">rename</link>
constraints (Peter Eisentraut)
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title><command>ALTER</></title>
<itemizedlist>
<listitem>
<para>
Reduce need to rebuild tables and indexes for certain <link
linkend="SQL-ALTERTABLE"><command>ALTER TABLE</command></link>
... <literal>ALTER COLUMN TYPE</> operations (Noah Misch)
</para>
<para>
Increasing the length limit for a <type>varchar</> or <type>varbit</>
column, or removing the limit altogether, no longer requires a table
rewrite. Similarly, increasing the allowable precision of a
<type>numeric</> column, or changing a column from constrained
<type>numeric</> to unconstrained <type>numeric</>, no longer
requires a table rewrite. Table rewrites are also avoided in similar
cases involving the <type>interval</>, <type>timestamp</>, and
<type>timestamptz</> types.
</para>
</listitem>
<listitem>
<para>
Avoid having <link linkend="SQL-ALTERTABLE"><command>ALTER
TABLE</command></link> revalidate foreign key constraints in some
cases where it is not necessary (Noah Misch)
</para>
</listitem>
<listitem>
<para>
Add <literal>IF EXISTS</> options to some <command>ALTER</command>
commands (Pavel Stehule)
</para>
<para>
For example, <command>ALTER FOREIGN TABLE IF EXISTS foo RENAME
TO bar</command>.
</para>
</listitem>
<listitem>
<para>
Add <link linkend="SQL-ALTERFOREIGNDATAWRAPPER"><command>ALTER
FOREIGN DATA WRAPPER</command></link> ... <literal>RENAME</>
and <link linkend="SQL-ALTERSERVER"><command>ALTER
SERVER</command></link> ... <literal>RENAME</> (Peter Eisentraut)
</para>
</listitem>
<listitem>
<para>
Add <link linkend="SQL-ALTERDOMAIN"><command>ALTER
DOMAIN</command></link> ... <literal>RENAME</> (Peter Eisentraut)
</para>
<para>
You could already rename domains using <command>ALTER
TYPE</command>.
</para>
</listitem>
<listitem>
<para>
Throw an error for <command>ALTER DOMAIN</command> ... <literal>DROP
CONSTRAINT</> on a nonexistent constraint (Peter Eisentraut) </para>
<para>
An <literal>IF EXISTS</> option has been added to provide the
previous behavior.
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title><link linkend="SQL-CREATETABLE"><command>CREATE TABLE</></link></title>
<itemizedlist>
<listitem>
<para>
Allow <command>CREATE TABLE (LIKE ...)</command> from foreign
tables, views, and composite types (Peter Eisentraut)
</para>
<para>
For example, this allows a table to be created whose schema matches a
view.
</para>
</listitem>
<listitem>
<para>
Fix <command>CREATE TABLE (LIKE ...)</command> to avoid index name
conflicts when copying index comments (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Fix <command>CREATE TABLE</command> ... <literal>AS EXECUTE</>
to handle <literal>WITH NO DATA</> and column name specifications
(Tom Lane)
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title>Object Permissions</title>
<itemizedlist>
<listitem>
<para>
Add a <link
linkend="SQL-CREATEVIEW"><literal>security_barrier</></link>
option for views (KaiGai Kohei, Robert Haas)
</para>
<para>
This option prevents optimizations that might allow view-protected
data to be exposed to users, for example pushing a clause involving
an insecure function into the <literal>WHERE</> clause of the view.
Such views can be expected to perform more poorly than ordinary
views.
</para>
</listitem>
<listitem> <para>
Add a new <link
linkend="SQL-CREATEFUNCTION"><literal>LEAKPROOF</></link> function
attribute to mark functions that can safely be pushed down
into <literal>security_barrier</> views (KaiGai Kohei)
</para>
</listitem>
<listitem>
<para>
Add support for privileges on data types (Peter Eisentraut)
</para>
<para>
This adds support for the <acronym>SQL</>-conforming
<literal>USAGE</> privilege on types and domains. The intent is
to be able to restrict which users can create dependencies on types,
since such dependencies limit the owner's ability to alter the type.
</para>
</listitem>
<listitem>
<para>
Check for <command>INSERT</command> privileges in <command>SELECT
INTO</command> / <command>CREATE TABLE AS</command> (KaiGai Kohei)
</para>
<para>
Because the object is being created by <command>SELECT INTO</command>
or <command>CREATE TABLE AS</command>, the creator would ordinarily
have insert permissions; but there are corner cases where this is not
true, such as when <literal>ALTER DEFAULT PRIVILEGES</> has removed
such permissions.
</para>
</listitem>
</itemizedlist>
</sect4>
</sect3>
<sect3>
<title>Utility Operations</title>
<itemizedlist>
<listitem>
<para>
Allow <link linkend="SQL-VACUUM"><command>VACUUM</></link> to more
easily skip pages that cannot be locked (Simon Riggs, Robert Haas)
</para>
<para>
This change should greatly reduce the incidence of <command>VACUUM</>
getting <quote>stuck</> waiting for other sessions.
</para>
</listitem>
<listitem>
<para>
Make <link linkend="SQL-EXPLAIN"><command>EXPLAIN</></link>
<literal>(BUFFERS)</> count blocks dirtied and written (Robert Haas)
</para>
</listitem>
<listitem>
<para>
Make <command>EXPLAIN ANALYZE</command> report the number of rows
rejected by filter steps (Marko Tiikkaja) </para>
</listitem>
<listitem>
<para>
Allow <command>EXPLAIN ANALYZE</command> to avoid timing overhead when
time values are not wanted (Tomas Vondra)
</para>
<para>
This is accomplished by setting the new <literal>TIMING</> option to
<literal>FALSE</>.
</para>
</listitem>
</itemizedlist>
</sect3>
<sect3>
<title>Data Types</title>
<itemizedlist>
<listitem>
<para>
Add support for <link linkend="rangetypes">range data types</link>
(Jeff Davis, Tom Lane, Alexander Korotkov)
</para>
<para>
A range data type stores a lower and upper bound belonging to its
base data type. It supports operations like contains, overlaps, and
intersection.
</para>
</listitem>
<listitem>
<para>
Add a <link linkend="datatype-json"><type>JSON</type></link>
data type (Robert Haas)
</para>
<para>
This type stores <acronym>JSON</acronym> (JavaScript Object Notation)
data with proper validation.
</para>
</listitem>
<listitem>
<para>
Add <link
linkend="functions-json"><function>array_to_json()</></link>
and <function>row_to_json()</> (Andrew Dunstan)
</para>
</listitem>
<listitem>
<para>
Add a <link linkend="datatype-serial"><type>SMALLSERIAL</></link>
data type (Mike Pultz)
</para>
<para>
This is like <type>SERIAL</>, except it stores the sequence in
a two-byte integer column (<type>int2</>).
</para>
</listitem>
<listitem> <para>
Allow <link linkend="SQL-CREATEDOMAIN">domains</link> to be
declared <literal>NOT VALID</> (Álvaro Herrera)
</para>
<para>
This option can be set at domain creation time, or via <command>ALTER
DOMAIN</command> ... <literal>ADD CONSTRAINT</> ... <literal>NOT
VALID</>. <command>ALTER DOMAIN</command> ... <literal>VALIDATE
CONSTRAINT</> fully validates the constraint.
</para>
</listitem>
<listitem>
<para>
Support more locale-specific formatting options for the <link
linkend="datatype-money"><type>money</></link> data type (Tom Lane)
</para>
<para>
Specifically, honor all the POSIX options for ordering of the value,
sign, and currency symbol in monetary output. Also, make sure that
the thousands separator is only inserted to the left of the decimal
point, as required by POSIX.
</para>
</listitem>
<listitem>
<para>
Add bitwise <quote>and</>, <quote>or</>, and <quote>not</>
operators for the <type>macaddr</> data type (Brendan Jurd)
</para>
</listitem>
<listitem>
<para>
Allow <link
linkend="functions-xml-processing"><function>xpath()</></link> to
return a single-element <acronym>XML</acronym> array when supplied a
scalar value (Florian Pflug)
</para>
<para>
Previously, it returned an empty array. This change will also
cause <function>xpath_exists()</> to return true, not false,
for such expressions.
</para>
</listitem>
<listitem>
<para>
Improve <acronym>XML</acronym> error handling to be more robust
(Florian Pflug)
</para>
</listitem>
</itemizedlist>
</sect3>
<sect3>
<title>Functions</title>
<itemizedlist>
<listitem>
<para>
Allow non-superusers to use <link
linkend="functions-admin-signal"><function>pg_cancel_backend()</></link>
and <link linkend="functions-admin-signal"><function>pg_terminate_backend()</></link>
on other sessions belonging to the same user
(Magnus Hagander, Josh Kupershmidt, Dan Farina)
</para>
<para>
Previously only superusers were allowed to use these functions.
</para>
</listitem>
<listitem>
<para>
Allow importing and exporting of transaction snapshots (Joachim
Wieland, Tom Lane)
</para>
<para>
This allows multiple transactions to share identical views of the
database state.
Snapshots are exported via <link
linkend="functions-snapshot-synchronization"><function>pg_export_snapshot()</></link>
and imported via <link linkend="SQL-SET-TRANSACTION"><command>SET
TRANSACTION SNAPSHOT</command></link>. Only snapshots from
currently-running transactions can be imported.
</para>
</listitem>
<listitem>
<para>
Support <link
linkend="functions-info-catalog-table"><literal>COLLATION
FOR</></link> on expressions (Peter Eisentraut)
</para>
<para>
This returns a string representing the collation of the expression.
</para>
</listitem>
<listitem>
<para>
Add <link
linkend="functions-info-schema-table"><function>pg_opfamily_is_visible()</></link>
(Josh Kupershmidt)
</para>
</listitem>
<listitem>
<para>
Add a <type>numeric</> variant of <link
linkend="functions-admin-dbsize"><function>pg_size_pretty()</></link>
for use with <function>pg_xlog_location_diff()</> (Fujii Masao)
</para>
</listitem>
<listitem>
<para>
Add a <link
linkend="functions-info-session-table"><function>pg_trigger_depth()</></link>
function (Kevin Grittner)
</para>
<para>
This reports the current trigger call depth.
</para>
</listitem>
<listitem>
<para>
Allow <link linkend="functions-aggregate-table"><function>string_agg()</></link>
to process <type>bytea</> values (Pavel Stehule)
</para>
</listitem>
<listitem>
<para>
Fix regular expressions in which a back-reference occurs within
a larger quantified subexpression (Tom Lane)
</para>
<para>
For example, <literal>^(\w+)( \1)+$</>. Previous releases did not
check that the back-reference actually matched the first occurrence.
</para>
</listitem>
</itemizedlist>
</sect3>
<sect3>
<title><link linkend="information-schema">Information Schema</link></title>
<itemizedlist>
<listitem>
<para>
Add information schema views
<structname>role_udt_grants</>, <structname>udt_privileges</>,
and <structname>user_defined_types</> (Peter Eisentraut)
</para>
</listitem>
<listitem>
<para>
Add composite-type attributes to the
information schema <structname>element_types</> view
(Peter Eisentraut)
</para>
</listitem>
<listitem>
<para>
Implement <structfield>interval_type</> columns in the information
schema (Peter Eisentraut)
</para>
<para>
Formerly these columns read as nulls.
</para>
</listitem>
<listitem>
<para>
Implement collation-related columns in the information schema
<structname>attributes</>, <structname>columns</>,
<structname>domains</>, and <structname>element_types</>
views (Peter Eisentraut)
</para>
</listitem>
<listitem>
<para>
Implement the <structfield>with_hierarchy</> column in the
information schema <structname>table_privileges</> view (Peter
Eisentraut)
</para>
</listitem>
<listitem>
<para>
Add display of sequence <literal>USAGE</> privileges to information
schema (Peter Eisentraut)
</para>
</listitem>
<listitem>
<para>
Make the information schema show default privileges (Peter
Eisentraut)
</para>
<para>
Previously, non-empty default permissions were not represented in the
views.
</para>
</listitem>
</itemizedlist>
</sect3>
<sect3>
<title>Server-Side Languages</title>
<sect4>
<title><link linkend="plpgsql">PL/pgSQL</link> Server-Side Language</title>
<itemizedlist>
<listitem>
<para>
Allow the PL/pgSQL <command>OPEN</> cursor command to supply
parameters by name (Yeb Havinga)
</para>
</listitem>
<listitem>
<para>
Add a <command>GET STACKED DIAGNOSTICS</command> PL/pgSQL command
to retrieve exception info (Pavel Stehule)
</para>
</listitem>
<listitem>
<para>
Speed up PL/pgSQL array assignment by caching type information
(Pavel Stehule)
</para>
</listitem>
<listitem>
<para>
Improve performance and memory consumption for long chains of
<literal>ELSIF</> clauses (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Output the function signature, not just the name, in PL/pgSQL
error messages (Pavel Stehule)
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title><link linkend="plpython">PL/Python</link> Server-Side Language</title>
<itemizedlist>
<listitem>
<para>
Add PL/Python <acronym>SPI</acronym> cursor support (Jan
Urbanski)
</para>
<para>
This allows PL/Python to read partial result sets.
</para>
</listitem>
<listitem>
<para>
Add result metadata functions to PL/Python (Peter Eisentraut)
</para>
<para>
Specifically, this adds result object functions
<literal>.colnames</literal>, <literal>.coltypes</literal>, and
<literal>.coltypmods</literal>.
</para>
</listitem>
<listitem>
<para>
Remove support for Python 2.2 (Peter Eisentraut)
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title><link linkend="xfunc-sql">SQL</link> Server-Side Language</title>
<itemizedlist>
<listitem>
<para>
Allow <acronym>SQL</acronym>-language functions to reference
parameters by name (Matthew Draper)
</para>
<para>
To use this, simply name the function arguments and then reference
the argument names in the <acronym>SQL</acronym> function body.
</para>
</listitem>
</itemizedlist>
</sect4>
</sect3>
<sect3>
<title>Client Applications</title>
<itemizedlist>
<listitem>
<para>
Add <link linkend="APP-INITDB"><application>initdb</></link>
options <option>--auth-local</> and <option>--auth-host</>
(Peter Eisentraut)
</para>
<para>
This allows separate control of <literal>local</> and
<literal>host</> <filename>pg_hba.conf</filename> authentication
settings. <option>--auth</> still controls both.
</para>
</listitem>
<listitem>
<para>
Add <option>--replication</>/<option>--no-replication</> flags to
<link linkend="APP-CREATEUSER"><application>createuser</></link>
to control replication permission (Fujii Masao)
</para>
</listitem>
<listitem>
<para>
Add the <option>--if-exists</> option to <link
linkend="APP-DROPDB"><application>dropdb</></link> and <link
linkend="APP-DROPUSER"><application>dropuser</></link> (Josh
Kupershmidt)
</para>
</listitem>
<listitem>
<para>
Give command-line tools the ability to specify the name of the
database to connect to, and fall back to <literal>template1</>
if a <literal>postgres</> database connection fails (Robert Haas)
</para>
</listitem>
</itemizedlist>
<sect4>
<title><link linkend="APP-PSQL"><application>psql</></link></title>
<itemizedlist>
<listitem>
<para>
Add a display mode to auto-expand output based on the
display width (Peter Eisentraut)
</para>
<para>
This adds the <literal>auto</> option to the <command>\x</>
command, which switches to the expanded mode when the normal
output would be wider than the screen.
</para>
</listitem>
<listitem>
<para>
Allow inclusion of a script file that is named relative to the
directory of the file from which it was invoked (Gurjeet Singh)
</para>
<para>
This is done with a new command <command>\ir</>.
</para>
</listitem>
<listitem>
<para>
Add support for non-<acronym>ASCII</acronym> characters in
<application>psql</> variable names (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Add support for major-version-specific <filename>.psqlrc</> files
(Bruce Momjian)
</para>
<para>
<application>psql</> already supported minor-version-specific
<filename>.psqlrc</> files.
</para>
</listitem>
<listitem>
<para>
Provide environment variable overrides for <application>psql</>
history and startup file locations (Andrew Dunstan)
</para>
<para>
<envar>PSQL_HISTORY</envar> and <envar>PSQLRC</envar> now
determine these file names if set.
</para>
</listitem>
<listitem>
<para>
Add a <command>\setenv</> command to modify
the environment variables passed to child processes (Andrew Dunstan)
</para>
</listitem>
<listitem>
<para>
Name <application>psql</>'s temporary editor files with a
<filename>.sql</> extension (Peter Eisentraut)
</para>
<para>
This allows extension-sensitive editors to select the right mode.
</para>
</listitem>
<listitem>
<para>
Allow <application>psql</> to use zero-byte field and record
separators (Peter Eisentraut)
</para>
<para>
Various shell tools use zero-byte (NUL) separators,
e.g. <application>find</>.
</para>
</listitem>
<listitem>
<para>
Make the <command>\timing</> option report times for
failed queries (Magnus Hagander)
</para>
<para>
Previously times were reported only for successful queries.
</para>
</listitem>
<listitem>
<para>
Unify and tighten <application>psql</>'s treatment of <command>\copy</>
and SQL <command>COPY</> (Noah Misch) </para>
<para>
This fix makes failure behavior more predictable and honors
<command>\set ON_ERROR_ROLLBACK</>.
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title>Informational Commands</title>
<itemizedlist>
<listitem>
<para>
Make <command>\d</> on a sequence show the
table/column name owning it (Magnus Hagander)
</para>
</listitem>
<listitem>
<para>
Show statistics target for columns in <command>\d+</> (Magnus
Hagander)
</para>
</listitem>
<listitem>
<para>
Show role password expiration dates in <command>\du</>
(Fabrízio de Royes Mello)
</para>
</listitem>
<listitem>
<para>
Display comments for casts, conversions, domains, and languages
(Josh Kupershmidt)
</para>
<para>
These are included in the output of <command>\dC+</>,
<command>\dc+</>, <command>\dD+</>, and <command>\dL</> respectively.
</para>
</listitem>
<listitem>
<para>
Display comments for <acronym>SQL</acronym>/<acronym>MED</acronym>
objects (Josh Kupershmidt)
</para>
<para>
These are included in the output of <command>\des+</>,
<command>\det+</>, and <command>\dew+</> for foreign servers, foreign
tables, and foreign data wrappers respectively.
</para>
</listitem>
<listitem>
<para>
Change <command>\dd</> to display comments only for object types
without their own backslash command (Josh Kupershmidt)
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title>Tab Completion</title>
<itemizedlist>
<listitem>
<para>
In <application>psql</> tab completion, complete <acronym>SQL</>
keywords in either upper or lower case according to the new <link
linkend="APP-PSQL-variables"><literal>COMP_KEYWORD_CASE</></link>
setting (Peter Eisentraut)
</para>
</listitem>
<listitem>
<para>
Add tab completion support for
<command>EXECUTE</command> (Andreas Karlsson)
</para>
</listitem>
<listitem>
<para>
Allow tab completion of role references in
<command>GRANT</command>/<command>REVOKE</command> (Peter
Eisentraut)
</para>
</listitem>
<listitem>
<para>
Allow tab completion of file names to supply quotes, when necessary
(Noah Misch)
</para>
</listitem>
<listitem>
<para>
Change tab completion support for
<command>TABLE</command> to also include views (Magnus Hagander)
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title><link linkend="APP-PGDUMP"><application>pg_dump</></link></title>
<itemizedlist>
<listitem>
<para>
Add an <option>--exclude-table-data</> option to
<application>pg_dump</> (Andrew Dunstan)
</para>
<para>
This allows dumping of a table's definition but not its data,
on a per-table basis.
</para>
</listitem>
<listitem>
<para>
Add a <option>--section</> option to <application>pg_dump</> and <application>pg_restore</> (Andrew Dunstan)
</para>
<para>
Valid values are <literal>pre-data</>, <literal>data</>,
and <literal>post-data</>. The option can be
given more than once to select two or more sections.
</para>
</listitem>
<listitem>
<para>
Make <link
linkend="APP-PG-DUMPALL"><application>pg_dumpall</></link> dump all
roles first, then all configuration settings on roles (Phil Sorber)
</para>
<para>
This allows a role's configuration settings to mention other
roles without generating an error.
</para>
</listitem>
<listitem>
<para>
Allow <application>pg_dumpall</> to avoid errors if the
<literal>postgres</> database is missing in the new cluster
(Robert Haas)
</para>
</listitem>
<listitem>
<para>
Dump foreign server user mappings in user name order (Peter
Eisentraut)
</para>
<para>
This helps produce deterministic dump files.
</para>
</listitem>
<listitem>
<para>
Dump operators in a predictable order (Peter Eisentraut)
</para>
</listitem>
<listitem>
<para>
Tighten rules for when extension configuration tables are dumped
by <application>pg_dump</> (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Make <application>pg_dump</> emit more useful dependency
information (Tom Lane)
</para>
<para>
The dependency links included in archive-format dumps were formerly
of very limited use, because they frequently referenced objects that
appeared nowhere in the dump. Now they represent actual dependencies
(possibly indirect) among the dumped objects.
</para>
</listitem>
<listitem> <para>
Improve <application>pg_dump</>'s performance when dumping many
database objects (Tom Lane)
</para>
</listitem>
</itemizedlist>
</sect4>
</sect3>
<sect3>
<title><link linkend="libpq"><application>libpq</></link></title>
<itemizedlist>
<listitem>
<para>
Allow <application>libpq</> connection strings to have the format of a
<link linkend="libpq-connstring"><acronym>URI</acronym></link>
(Alexander Shulgin)
</para>
<para>
The syntax begins with <literal>postgres://</>. This can allow
applications to avoid implementing their own parser for URIs
representing database connections.
</para>
</listitem>
<listitem>
<para>
Add a <link linkend="libpq-connect-sslcompression">connection
option</link> to disable <acronym>SSL</acronym> compression
(Laurenz Albe)
</para>
<para>
This can be used to remove the overhead of <acronym>SSL</acronym>
compression on fast networks.
</para>
</listitem>
<listitem>
<para>
Add a <link linkend="libpq-single-row-mode">single-row processing
mode</link> for better handling of large result sets
(Kyotaro Horiguchi, Marko Kreen)
</para>
<para>
Previously, <application>libpq</> always collected the entire query
result in memory before passing it back to the application.
</para>
</listitem>
<listitem>
<para>
Add <literal>const</> qualifiers to the declarations of the functions
<function>PQconnectdbParams</>, <function>PQconnectStartParams</>,
and <function>PQpingParams</> (Lionel Elie Mamane)
</para>
</listitem>
<listitem>
<para>
Allow the <filename>.pgpass</> file to include escaped characters
in the password field (Robert Haas)
</para> </listitem>
<listitem>
<para>
Make library functions use <function>abort()</> instead of
<function>exit()</> when it is necessary to terminate the process
(Peter Eisentraut)
</para>
<para>
This choice does not interfere with the normal exit codes used by the
program, and generates a signal that can be caught by the caller.
</para>
</listitem>
</itemizedlist>
</sect3>
<sect3>
<title>Source Code</title>
<itemizedlist>
<listitem>
<para>
Remove dead ports (Peter Eisentraut)
</para>
<para>
The following platforms are no longer supported: dgux,
nextstep, sunos4, svr4, ultrix4, univel, bsdi.
</para>
</listitem>
<listitem>
<para>
Add support for building with <link linkend="install-windows">MS
Visual Studio 2010</link> (Brar Piening)
</para>
</listitem>
<listitem>
<para>
Enable compiling with the MinGW-w64 32-bit compiler (Lars Kanis)
</para>
</listitem>
<listitem>
<para>
Install <filename>plpgsql.h</> into <filename>include/server</> during installation
(Heikki Linnakangas)
</para>
</listitem>
<listitem>
<para>
Improve the latch facility to include detection of postmaster death
(Peter Geoghegan, Heikki Linnakangas, Tom Lane)
</para>
<para>
This eliminates one of the main reasons that background processes
formerly had to wake up to poll for events.
</para>
</listitem>
<listitem>
<para>
Use C flexible array members, where supported (Peter Eisentraut) </para>
</listitem>
<listitem>
<para>
Improve the concurrent transaction regression tests
(<application>isolationtester</>) (Noah Misch)
</para>
</listitem>
<listitem>
<para>
Modify <application>thread_test</> to create its test files in
the current directory, rather than <filename>/tmp</> (Bruce Momjian)
</para>
</listitem>
<listitem>
<para>
Improve flex and bison warning and error reporting (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Add memory barrier support (Robert Haas)
</para>
<para>
This is currently unused.
</para>
</listitem>
<listitem>
<para>
Modify pgindent to use a typedef file (Bruce Momjian)
</para>
</listitem>
<listitem>
<para>
Add a hook for processing messages due to be sent to the server
log (Martin Pihlak)
</para>
</listitem>
<listitem>
<para>
Add object access hooks for <command>DROP</command> commands
(KaiGai Kohei)
</para>
</listitem>
<listitem>
<para>
Centralize <command>DROP</command> handling for some object types
(KaiGai Kohei)
</para>
</listitem>
<listitem>
<para>
Add a <application>pg_upgrade</> test suite (Peter Eisentraut)
</para>
</listitem>
<listitem>
<para>
Sync regular expression code with <acronym>TCL</acronym> 8.5.11
and improve internal processing (Tom Lane) </para>
</listitem>
<listitem>
<para>
Move <acronym>CRC</acronym> tables to libpgport, and provide them
in a separate include file (Daniel Farina)
</para>
</listitem>
<listitem>
<para>
Add options to <application>git_changelog</> for use in major
release note creation (Bruce Momjian)
</para>
</listitem>
<listitem>
<para>
Support Linux's <filename>/proc/self/oom_score_adj</> API (Tom Lane)
</para>
</listitem>
</itemizedlist>
</sect3>
<sect3>
<title>Additional Modules</title>
<itemizedlist>
<listitem>
<para>
Improve efficiency of <link linkend="dblink">dblink</link> by using
libpq's new single-row processing mode (Kyotaro Horiguchi, Marko
Kreen)
</para>
<para>
This improvement does not apply to
<function>dblink_send_query()</>/<function>dblink_get_result()</>.
</para>
</listitem>
<listitem>
<para>
Support <literal>force_not_null</> option in <link
linkend="file-fdw">file_fdw</link> (Shigeru Hanada)
</para>
</listitem>
<listitem>
<para>
Implement dry-run mode for <link
linkend="pgarchivecleanup"><application>pg_archivecleanup</></link>
(Gabriele Bartolini)
</para>
<para>
This only outputs the names of files to be deleted.
</para>
</listitem>
<listitem>
<para>
Add new <link linkend="pgbench">pgbench</link> switches
<option>--unlogged-tables</>, <option>--tablespace</>, and
<option>--index-tablespace</> (Robert Haas)
</para> </listitem>
<listitem>
<para>
Change <link
linkend="pgtestfsync"><application>pg_test_fsync</></link> to test
for a fixed amount of time, rather than a fixed number of cycles
(Bruce Momjian)
</para>
<para>
The <option>-o</>/cycles option was removed, and
<option>-s</>/seconds added.
</para>
</listitem>
<listitem>
<para>
Add a <link
linkend="pgtesttiming"><application>pg_test_timing</></link>
utility to measure clock monotonicity and timing overhead (Ants
Aasma, Greg Smith)
</para>
</listitem>
<listitem>
<para>
Add a <link linkend="tcn">tcn</link> (triggered change notification)
module to generate <command>NOTIFY</command> events on table changes
(Kevin Grittner)
</para>
</listitem>
</itemizedlist>
<sect4>
<title><link linkend="pgupgrade"><application>pg_upgrade</></link></title>
<itemizedlist>
<listitem>
<para>
Adjust <application>pg_upgrade</> environment variables (Bruce
Momjian)
</para>
<para>
Rename data, bin, and port environment
variables to begin with <literal>PG</>, and support
<envar>PGPORTOLD</envar>/<envar>PGPORTNEW</envar>, to replace
<envar>PGPORT</envar>.
</para>
</listitem>
<listitem>
<para>
Overhaul <application>pg_upgrade</> logging and failure reporting
(Bruce Momjian)
</para>
<para>
Create four append-only log files, and delete them on success.
Add <option>-r</>/<option>--retain</> option to unconditionally
retain these files. Also remove <application>pg_upgrade</> options
<option>-g</>/<option>-G</>/<option>-l</> options as unnecessary,
and tighten log file permissions.
</para>
</listitem>
<listitem> <para>
Make <application>pg_upgrade</> create a script to incrementally
generate more accurate optimizer statistics (Bruce Momjian)
</para>
<para>
This reduces the time needed to generate minimal cluster statistics
after an upgrade.
</para>
</listitem>
<listitem>
<para>
Allow <application>pg_upgrade</> to upgrade an old cluster that
does not have a <literal>postgres</> database (Bruce Momjian)
</para>
</listitem>
<listitem>
<para>
Allow <application>pg_upgrade</> to handle cases where some
old or new databases are missing, as long as they are empty
(Bruce Momjian)
</para>
</listitem>
<listitem>
<para>
Allow <application>pg_upgrade</> to handle configuration-only
directory installations (Bruce Momjian)
</para>
</listitem>
<listitem>
<para>
In <application>pg_upgrade</>, add <option>-o</>/<option>-O</>
options to pass parameters to the servers (Bruce Momjian)
</para>
<para>
This is useful for configuration-only directory installs.
</para>
</listitem>
<listitem>
<para>
Change <application>pg_upgrade</> to use port 50432 by default
(Bruce Momjian)
</para>
<para>
This helps avoid unintended client connections during the upgrade.
</para>
</listitem>
<listitem>
<para>
Reduce cluster locking in <application>pg_upgrade</> (Bruce
Momjian)
</para>
<para>
Specifically, only lock the old cluster if link mode is used,
and do it right after the schema is restored.
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title><link linkend="pgstatstatements"><application>pg_stat_statements</></link></title>
<itemizedlist>
<listitem>
<para>
Allow <application>pg_stat_statements</> to aggregate similar
queries via SQL text normalization (Peter Geoghegan, Tom Lane)
</para>
<para>
Users with applications that use non-parameterized SQL will now
be able to monitor query performance without detailed log analysis.
</para>
</listitem>
<listitem>
<para>
Add dirtied and written block counts and read/write times to
<application>pg_stat_statements</> (Robert Haas, Ants Aasma)
</para>
</listitem>
<listitem>
<para>
Prevent <application>pg_stat_statements</> from double-counting
<command>PREPARE</command> and <command>EXECUTE</command> commands
(Tom Lane)
</para>
</listitem>
</itemizedlist>
</sect4>
<sect4>
<title><link linkend="sepgsql">sepgsql</link></title>
<itemizedlist>
<listitem>
<para>
Support <literal>SECURITY LABEL</> on global objects (KaiGai
Kohei, Robert Haas)
</para>
<para>
Specifically, add security labels to databases,
tablespaces, and roles.
</para>
</listitem>
<listitem>
<para>
Allow sepgsql to honor database labels (KaiGai Kohei)
</para>
</listitem>
<listitem>
<para>
Perform sepgsql permission checks during the creation of various
objects (KaiGai Kohei)
</para>
</listitem>
<listitem>
<para>
Add <function>sepgsql_setcon()</> and related functions to control
the sepgsql security domain (KaiGai Kohei) </para>
</listitem>
<listitem>
<para>
Add a user space access cache to sepgsql to improve performance
(KaiGai Kohei)
</para>
</listitem>
</itemizedlist>
</sect4>
</sect3>
<sect3>
<title>Documentation</title>
<itemizedlist>
<listitem>
<para>
Add a rule to optionally build HTML documentation using the
stylesheet from the website (Magnus Hagander)
</para>
<para>
Use <command>gmake STYLE=website draft</>.
</para>
</listitem>
<listitem>
<para>
Improve <command>EXPLAIN</command> documentation (Tom Lane)
</para>
</listitem>
<listitem>
<para>
Document that user/database names are preserved with double-quoting
by command-line tools like <application>vacuumdb</> (Bruce
Momjian)
</para>
</listitem>
<listitem>
<para>
Document the actual string returned by the client for MD5
authentication (Cyan Ogilvie)
</para>
</listitem>
<listitem>
<para>
Deprecate use of <literal>GLOBAL</> and <literal>LOCAL</> in
<command>CREATE TEMP TABLE</> (Noah Misch)
</para>
<para>
<productname>PostgreSQL</> has long treated these keyword as no-ops,
and continues to do so; but in future they might mean what the SQL
standard says they mean, so applications should avoid using them.
</para>
</listitem>
</itemizedlist>
</sect3>
</sect2> </sect1>