1 <!-- doc/src/sgml/release-9.3.sgml -->
2 <!-- See header comment in release.sgml about typical markup -->
4 <sect1 id="release-9-3">
5 <title>Release 9.3</title>
8 <title>Release Date</title>
9 <simpara>2013-XX-XX, CURRENT AS OF 2013-04-20</simpara>
13 <title>Overview</title>
16 ADD HERE Major enhancements include:
19 <!-- This list duplicates items below, but without authors or details-->
22 The above items are explained in more detail in the sections below.
29 <title>Migration to Version 9.3</title>
32 A dump/restore using <link
33 linkend="APP-PG-DUMPALL"><application>pg_dumpall</></link>, or use
34 of <link linkend="pgupgrade"><application>pg_upgrade</></link>, is
35 required for those wishing to migrate data from any previous release.
39 Version 9.3 contains a number of changes that may affect compatibility
40 with previous releases. Observe the following incompatibilities:
44 <title>ADD HERE</title>
51 <title>Changes</title>
54 Below you will find a detailed account of the changes between
55 <productname>PostgreSQL</productname> 9.3 and the previous major
63 <title>Locking</title>
69 Prevent non-key-field row updates from locking foreign key rows
70 (Álvaro Herrera, Marti Raudsepp, Alexander Shulgin,
71 Noah Misch and Andres Freund)
75 This improves concurrency and reduces the probability of deadlocks.
76 UPDATEs on non-key columns use the new SELECT FOR NO KEY UPDATE lock
77 type, and foreign key checks use the new SELECT FOR KEY SHARE lock mode.
83 Add cache of local locks (Jeff Janes)
87 This speeds lock release at statement completion in transactions
88 that hold many locks; it is particularly useful for pg_dump.
97 <title>Indexes</title>
103 Add SP-GiST support for range data types (Alexander Korotkov)
109 Allow unlogged GiST indexes (Jeevan Chalke)
115 Improve concurrency of hash indexes (Robert Haas)
124 <title>Optimizer</title>
130 Improve the ability to detect indexable prefixes in regular
131 expressions (Tom Lane)
137 Collect and use histograms for range types (Alexander Korotkov)
143 Reduce optimizer overhead by discarding plans with unneeded cheaper
144 startup costs (Tom Lane)
150 Improve optimizer cost estimation for index access (Tom Lane)
159 <title>General Performance</title>
165 Add COPY FREEZE option to avoid the overhead of later marking
166 tuples as committed (Simon Riggs, Jeff Davis)
172 Improve performance of NUMERIC calculations (Kyotaro Horiguchi)
178 Improve grouping of sessions waiting for commit_delay (Peter
183 This improves the usefulness and behavior of commit_delay.
184 BACKWARD COMPATIBILITY
190 Implement a generic binary heap and use it for Merge-Append
191 operations (Abhijit Menon-Sen)
197 "Allow in-memory sorts to use their full memory allocation (Jeff Janes)
201 Users who have set work_mem based on the previous behavior should
202 revisit that setting.
208 Improve performance for transactions creating, rebuilding, or
209 dropping many relations (Jeff Janes, Tomas Vondra)
215 Improve performance of the CREATE TABLE ... ON COMMIT DELETE ROWS
216 clause by only issuing delete if the temporary table was accessed
223 Allow heap-only tuple updates on system tables (Andres Freund)
229 Have vacuum recheck visibility after it has removed expired tuples
234 This increases the chance of a page being marked as all-visible.
240 Split pgstat file in per-database and global files (Tomas Vondra)
244 This reduces the statistics management read and write overhead.
253 <title>Monitoring</title>
259 Add optional ability to checksum data pages and report corruption
260 (Simon Riggs, Jeff Davis, Greg Smith)
264 The checksum option can be set during initdb.
270 Allow pg_terminate_backend() to terminate other backends with
271 the same role (Dan Farina)
275 Previously, only superusers could terminate other sessions.
281 Allow the statistics collector to operate properly in cases where
282 the system clock goes backwards (Tom Lane)
286 Previously statistics collection would stop until the time again
287 reached the previously-stored latest time.
293 Add function to report the size of the GIN pending index insertion
298 The function is pgstatginindex() in pgstattuple.
307 <title>Authentication</title>
313 Improve LDAP error reporting and documentation (Peter Eisentraut)
319 Add support for LDAP authentication to be specified in URL format
326 Change the ssl_ciphers parameter to start with DEFAULT, rather
327 than ALL, then remove insecure ciphers (Magnus Hagander)
331 It is assumed DEFAULT is more appropriate cipher set.
337 Parse/load pg_ident.conf once, not during each connection (Amit
342 This is similar to how pg_hba.conf is processed.
351 <title>Server Settings</title>
357 Dramatically reduce System V shared memory usage (Robert Haas)
361 Instead, on Unix-like systems, mmap() is used for shared memory.
362 This eliminates the requirement of increasing System V shared
363 memory kernel parameters.
369 Allow the postmaster to listen on multiple Unix-domain sockets
374 This renames configuration parameter unix_socket_directory to
375 unix_socket_directories, which accepts a list of directories.
381 Add configuration variable lock_timeout to limit lock wait duration
382 (Zoltán Böszörményi)
388 Allow a directory of configuration files to be processed (Magnus
389 Hagander, Greg Smith, Selena Deckelmann)
393 The directory is specified as include_dir in server configuration file.
399 Increase the maximum initdb-configured value for shared_buffers
400 to 128MB (Robert Haas)
404 This is the maximum value initdb attempts to set in
405 postgresql.conf; the previous value was 32MB.
411 Require superuser privileges to set commit_delay because it
412 can now potentially delay other sessions (Simon Riggs)
413 BACKWARD COMPATIBILITY
420 Remove the external PID file on postmaster exit (Peter Eisentraut)
426 Have "session id" in log_line_prefix (%c) always output four hex
427 digits after the period (Bruce Momjian) COMPATIBILITY
438 <title>Replication and Recovery</title>
444 Allow a streaming replication standbys to follow a timeline switch (Heikki Linnakangas)
448 This allows streaming standbys to feed from newly-promoted slaves.
449 Previously slaves required access to a WAL archive directory to
456 Add SQL functions pg_backup_in_progress() and pg_backup_start_time() (Gilles Darold)
460 These functions report the status of base backups.
466 Improve performance of streaming replication log shipping and
467 standby promotion (Andres Freund, Simon Riggs)
473 Add the last checkpoint's redo location to pg_controldata's output
478 This information is useful for determining the WAL files needed for
485 Allow tooling like pg_receivexlog to run on computers with different
486 architectures (Heikki Linnakangas)
492 Have pg_basebackup --write-recovery-conf output a minimal
493 recovery.conf (Zoltán Böszörményi, Magnus Hagander)
497 This simplifies setting up a standby server.
503 Allow pg_receivexlog and pg_basebackup -X to handle streaming
504 timeline switches (Heikki Linnakangas)
510 Add wal_receiver_timeout parameter to control the WAL receiver
511 timeout (Amit Kapila)
515 This allows more rapid detection of connection failure. No longer set
516 wal_receiver_status_interval?
522 Rename replication_timeout to wal_sender_timeout (Amit Kapila)
526 BACKWARD COMPATIBILITY
527 This setting controls the WAL sender timeout.
534 <title>Write-Ahead Log (WAL)</title>
540 Store WAL in a continuous stream, rather than skipping the last
541 16MB segment every 4GB (Heikki Linnakangas) BACKWARD COMPATIBLE BREAK
547 Restructure WAL files to better handle timeline changes during
548 recovery (Heikki Linnakangas)
554 Restructure WAL files to use a more compact storage format (Heikki Linnakangas)
565 <title>Queries</title>
571 Implement SQL-standard LATERAL for FROM-clause subqueries and
572 function calls (Tom Lane)
576 This is useful in allowing FROM subqueries and functions to reference
577 output from tables in the FROM clause. The LATERAL keyword is optional
584 Add support for piping COPY and psql \copy to/from an external program (Etsuro
591 Improve query string error location reporting (Tom Lane)
595 Only CREATE SCHEMA ... IF NOT EXISTS? If so, remove it.
604 <title>Object Manipulation</title>
610 Add support to event triggers (Dimitri Fontaine, Tom Lane)
614 This allows C functions to be called when specific commands are run.
620 Allow a multi-row VALUES clause in rules to reference OLD/NEW (Tom Lane)
626 Add CREATE SCHEMA ... IF NOT EXIST clause (Fabrízio de
633 Throw an error if expiring tuple is again updated or deleted (Kevin Grittner)
640 Have DROP OWNED only remove user-matching GRANTs on shared objects,
641 e.g. databases, tablespaces (Álvaro Herrera)
645 Previously it tried to remove such objects, leading to an error.
651 Have REASSIGN OWNED also change ownership of shared objects (Álvaro
659 <title><link linkend="SQL-CREATETABLE"><command>CREATE TABLE</></link></title>
665 No longer output messages about implicit index and sequence creation (Robert Haas)
669 These messages now appear with DEBUG1-level output.
675 Allow CREATE TABLE IF NOT EXIST to succeed for a non-existent schema
680 Previously, it threw an error if the schema did not exist.
689 <title>Constraints</title>
695 Change ON UPDATE SET NULL/SET DEFAULT foreign key actions to affect
696 all referenced columns, not just those referenced in the UPDATE
701 Previously only columns referenced in the UPDATE were set to null or DEFAULT.
702 BACKWARD COMPATIBILITY CHANGE
708 Provide clients with constraint violation details as separate fields
713 This allows clients to retrieve table, column, data type, or constraint
714 name error details. Previously such information had to be extracted from
715 error strings. Client language support is required to access these
722 Internally store default foreign key matches (non-FULL, non-PARTIAL) as "simple" (Tom Lane)
726 These were previously stored as "&unspecified&".
727 This changes the value stored in system column
728 pg_constraint.confmatchtype. BACKWARD COMPATIBILITY CHANGE
737 <title><command>ALTER</></title>
743 Add the ALTER TYPE ... IF NOT EXISTS clause when adding enumerated type labels (Andrew
748 This is useful for conditional label creation in transaction blocks.
754 Add ALTER ROLE ALL SET to add settings to all users (Peter Eisentraut)
758 This allows settings to apply to all users in all databases. ALTER
759 DATABASE SET already allowed addition of settings for all users in a
760 single database. postgresql.conf has a similar effect.
766 Add support for ALTER RULE ... RENAME (Ali Dar)
775 <title><link linkend="rules-views"><command>VIEWs</></link></title>
781 Add a materialized view relations (Kevin Grittner)
785 Unlike ordinary views, where the base tables are read on every access,
786 materialized views create physical tables at creation or refresh time.
787 Access to the materialized view reads from these materialized physical
788 tables. There is no facility for incrementally refreshing materialized
789 views or auto-accessing them via base table access.
795 Make simple views auto-updatable (Dean Rasheed)
799 INSTEAD rules are still available for complex views.
805 Allow views and rules to handle cases where referenced tables are
806 renamed, or columns are renamed, added, or dropped (Tom Lane)
807 HOW DOES IT HANDLE A DROPPED REFERENCED COLUMN?
813 Add CREATE RECURSIVE VIEW syntax (Peter Eisentraut)
817 Internally this is translated into CREATE VIEW ... WITH RECURSIVE.
823 When converting a table to a view, remove its system columns (Tom Lane)
835 <title>Data Types</title>
841 Increase the maximum length of large objects from 2GB to 4TB (Nozomi
846 This change includes new libpq and server-side 64-bit-enabled functions.
852 Allow text timezone designations, e.g. "America/Chicago" when using the
853 ISO "T" timestamptz format (Bruce Momjian)
866 Add operators and functions to extract values from JSON data strings
873 Allow JSON data strings to be converted into records (Andrew Dunstan)
879 Add functions to convert values, records, and hstore data to JSON (Andrew Dunstan)
891 <title>Functions</title>
897 Add array_remove() and array_replace() functions (Marco Nenciarini, Gabriele Bartolini)
903 Allow concat() and format() to properly expand VARIADIC-labeled
904 arguments (Pavel Stehule)
910 Improve format() to handle field width and left/right alignment
917 Have to_char(), to_date(), and to_timestamp() properly handle
918 negative century designations (CC) (Bruce Momjian)
922 Previously the behavior was either wrong or inconsistent with
923 positive/AD handling, e.g. format mask 'IYYY-IW-DY'.
929 Have to_date() and to_timestamp() return proper results when mixing
930 ISO and Gregorian week/day designations (Bruce Momjian)
936 Cause pg_get_viewdef() to default to wrapping after every SELECT
937 target list and FROM entry (Marko Tiikkaja)
941 This causes view output, like from pg_dump, to be more narrow.
947 Have map_sql_value_to_xml_value() properly expand domains (Pavel
954 Force cached functions to be replanned if the search_path changes (Tom Lane)
958 Previously functions already run in the current session ignored
969 <title>Server-Side Languages</title>
975 Allow SPI functions to access the number of rows processed by COPY (Pavel
983 <title><link linkend="plpgsql">PL/pgSQL</link> Server-Side Language</title>
989 Allow PL/pgSQL to use RETURN with a composite-type expressions (Asif
994 Previously RETURN could only reference composite-type variables.
1000 Allow PL/pgSQL to access the number of rows processed by COPY (Pavel
1005 The command is GET DIAGNOSTICS x = ROW_COUNT.
1011 Allow greater flexibility in where keywords can be used in PL/pgSQL (Tom Lane)
1020 <title><link linkend="plpython">PL/Python</link> Server-Side Language</title>
1026 Add PL/Python result object string handler (Peter Eisentraut)
1030 This allows plpy.debug(rv) to output something reasonable.
1036 Have PL/Python convert oid values to a proper Python numeric type (Peter Eisentraut)
1042 Handle SPIErrors raised explicitly with PL/Python's RAISE the same as
1043 as internal SPI errors (Oskari Saarenmaa and Jan Urbanski)
1054 <title>Client Applications</title>
1060 Add command-line utility pg_isready to check if the server is ready
1061 to accept connections (Phil Sorber)
1067 Support multiple --table arguments for pg_restore, clusterdb,
1068 reindexdb, and vacuumdb (Josh Kupershmidt)
1072 This is similar to the pg_dump --table support.
1078 Add -d option to pg_dumpall, pg_basebackup, pg_receivexlog to
1079 specify the connection string (Amit Kapila)
1085 Allow pg_ctl --idempotent to a 'success' return code if the requested
1086 start/stop action fails, but the cluster is already in the requested
1087 state (Peter Eisentraut)
1093 Change pg_ctl to return an error code if start fails because the
1094 server is already running (Peter Eisentraut)
1100 Add libpq function PQconninfo() to return connection information
1101 (Zoltan Boszormenyi, Magnus Hagander)
1108 <title><link linkend="APP-PSQL"><application>psql</></link></title>
1114 Adjust function cost settings so psql tab completion and pattern
1115 searching is more efficient (Tom Lane)
1121 Improve psql tab completion (Jeff Janes, Peter Eisentraut)
1127 Allow the psql --single-transaction mode to work when reading from
1128 standard input (Fabien Coelho, Robert Haas)
1132 Previously this option only worked when reading from a file.
1138 Remove psql warning when connecting to an older server (Peter Eisentraut)
1142 The warning when connecting to a newer server was retained.
1149 <title>Backslash Commands</title>
1155 Add psql \watch command to repeatedly execute commands (Will
1162 Add psql command \gset to store query results in psql variables
1169 Add SSL information to psql's \conninfo command (Alastair Turner)
1175 Add "Security" label to psql \df+ output (Jon Erdman)
1181 Allow psql \l to accept a database name pattern (Peter Eisentraut)
1187 In psql, do not allow \connect to use defaults if there is no active
1188 connection (Bruce Momjian)
1192 This might be the case if the server had crashed.
1198 Properly reset state if psql's "\g file" command failed (Tom Lane)
1202 Previously failed commands discarded output from subsequent commands.
1211 <title>Output</title>
1217 Add a 'latex-longtable' output format to psql (Bruce Momjian)
1221 Longtable allows tables to span multiple pages.
1227 Add a border=3 output mode to the psql 'latex' format (Bruce Momjian)
1233 In psql tuples-only and expanded modes, no longer output "(No rows)"
1240 In psql, no longer print an empty line for unaligned, expanded
1241 output for zero rows (Peter Eisentraut)
1252 <title><link linkend="APP-PGDUMP"><application>pg_dump</></link></title>
1258 Add pg_dump --jobs to dump in parallel when using directory
1259 output format (Joachim Wieland)
1265 Have pg_dump output functions in a predictable order (Joel Jacobson)
1271 Fix tar files emitted by pg_dump and pg_basebackup to be POSIX
1272 conformant (Brian Weaver, Tom Lane)
1278 Add -d/--dbname option to pg_dump, for consistency with other client
1279 commands (Heikki Linnakangas)
1283 The database name could already be supplied last without a flag.
1292 <title><link linkend="APP-INITDB"><application>initdb</></link></title>
1298 Have initdb fsync the newly created data directory (Jeff Davis)
1302 This can be disabled by using --nosync.
1308 Add initdb --sync-only option to sync the data directory to durable
1309 storage (Bruce Momjian)
1313 This is used by pg_upgrade.
1319 Have initdb issue a warning about placing the data directory at the
1320 top of file system mount points (Bruce Momjian)
1331 <title>Source Code</title>
1337 Add an embedded list interface (Andres Freund)
1343 Add infrastructure to better support plug-in background worker
1344 processes (Álvaro Herrera)
1350 Create a centralized timeout API (Zoltán Böszörményi)
1356 Create libpgcommon and move pg_malloc() and other functions there
1357 (Álvaro Herrera, Andres Freund)
1361 This allows libpgport to be used solely for porting code.
1367 Standardize on naming of client-side memory allocation functions (Tom Lane)
1373 Add compiler designations to indicate some ereport() and elog()
1374 calls do not return (Peter Eisentraut, Andres Freund, Tom Lane,
1381 Allow options to be passed to the regression test output comparison
1382 utility via PG_REGRESS_DIFF_OPTS (Peter Eisentraut)
1388 Add isolation tests for CREATE INDEX CONCURRENTLY (Abhijit Menon-Sen)
1394 Remove typedefs for int2/int4 as they are better represented as int16/int32 (Peter Eisentraut)
1400 Fix install-strip on Mac OS X (Peter Eisentraut)
1406 Remove configure flag --disable-shared, as it is no longer used (Bruce Momjian)
1412 Rewrite pgindent in Perl (Andrew Dunstan)
1418 Add emacs macro to match Postgres perltidy formatting (Peter
1425 Run tool to check the keyword list when the backend grammar is changed (Tom Lane)
1431 Centralize flex and bison 'make' rules (Peter Eisentraut)
1435 This is useful for pgxs authors.
1441 Add Assert() functionality to client-side code for frontend code (Andrew Dunstan)
1447 Change many internal many backend functions to return OIDs rather
1448 than void (Dimitri Fontaine)
1452 This is useful for event triggers.
1458 Invent pre-commit/pre-prepare/pre-subcommit events for transaction
1459 callbacks (Tom Lane)
1463 Loadable modules that use transaction callbacks might need modification
1464 to handle these new event types.
1470 Add function pg_identify_object() to dump an object in
1471 machine-readable format (Álvaro Herrera)
1477 Add post-ALTER-object server hooks (KaiGai Kohei)
1483 Improve ability to detect official timezone abbreviation changes
1490 Add pkg-config support libpq and ecpg libraries (Peter Eisentraut)
1496 Remove src/tool/backend, now that the content is on the Postgres
1497 wiki (Bruce Momjian)
1503 Split out WAL reading as an independent facility (Heikki
1504 Linnakangas, Andres Freund)
1510 Allow PL/Python to support platform-specific include directories (Peter Eisentraut)
1516 Allow PL/Python on OS X to build against custom versions of Python
1526 <title>Additional Modules</title>
1532 Add a Postgres foreign data wrapper contrib module (Shigeru
1533 Hanada, KaiGai Kohei)
1537 This foreign data wrapper allows writes; potentially other
1538 foreign data wrappers can now support writes.
1544 Add pg_xlogdump contrib program (Andres Freund)
1550 Add support for indexing of regular-expression searches in
1551 contrib/pg_trgm (Alexander Korotkov)
1557 Improve pg_trgm handling of multibyte characters (Tom Lane)
1563 Have oid2name, pgbench, and vacuumlo set fallback_application_name (Amit Kapila)
1569 Improve output of pg_test_timing (Bruce Momjian)
1575 Improve output of pg_test_fsync (Peter Geoghegan)
1581 Improve dblink option validator (Tom Lane)
1592 <title><link linkend="pgupgrade"><application>pg_upgrade</></link></title>
1598 Allow pg_upgrade --jobs to do parallelism (Bruce Momjian)
1602 This allows parallel schema dump/restore of databases, as well as
1603 parallel copy/link of data files per tablespace.
1609 Have pg_upgrade create unix-domain sockets in the current directory
1610 (Bruce Momjian, Tom Lane)
1614 This reduces the possibility that someone will accidentally connect
1621 Have pg_upgrade --check mode properly detect the location of
1622 non-default socket directories (Bruce Momjian, Tom Lane)
1628 Improve performance of pg_upgrade for databases with many tables (Bruce Momjian)
1634 Increase pg_upgrade logging content by showing executed command
1635 (Álvaro Herrera)
1641 Improve pg_upgrade's status display during copy/link (Bruce Momjian)
1650 <title><link linkend="pgbench"><application>pgbench</></link></title>
1656 Add --foreign-keys option to pgbench (Jeff Janes)
1660 This adds foreign key constraints to tables, for use in foreign
1661 key performance testing.
1667 Allow pgbench to aggregate performance statistics and produce output
1668 every --aggregate-interval specified seconds (Tomas Vondra)
1674 Add pg_bench --sampling-rate option to control the percentage of
1675 transactions logged (Tomas Vondra)
1681 Reduce and improve the status message output of pgbench's
1682 initialization mode (Robert Haas, Peter Eisentraut)
1688 Add pgbench -q mode to print one output line every five seconds (Tomas Vondra)
1692 Output pgbench elapsed and estimated remaining time during
1693 initialization logging (Tomas Vondra)
1699 Allow pgbench to use a larger scale factor (Greg Smith)
1710 <title>Documentation</title>
1716 Allow EPUB-format documentation to be created (Peter Eisentraut)
1722 Update FreeBSD kernel configuration documentation (Brad Davis)
1728 Improve WINDOW function documentation (Bruce Momjian, Tom Lane)
1734 Add instructions for setting up the documentation tool chain on
1735 Mac OS X (Peter Eisentraut)
1741 Improve commit_delay documentation (Peter Geoghegan)