Release date: 2014-12-18
Major enhancements in PostgreSQL™ 9.4 include:
Add jsonb, a more capable and efficient data type for storing JSON data
Add new SQL command ALTER SYSTEM(7) for changing postgresql.conf configuration file entries
Reduce lock strength for some ALTER TABLE(7) commands
Allow materialized views to be refreshed without blocking concurrent reads
Add support for logical decoding of WAL data, to allow database changes to be streamed out in a customizable format
Allow background worker processes to be dynamically registered, started and terminated
The above items are explained in more detail in the sections below.
A dump/restore using pg_dumpall(1), or use of pg_upgrade(1), is required for those wishing to migrate data from any previous release.
Version 9.4 contains a number of changes that may affect compatibility with previous releases. Observe the following incompatibilities:
Tighten checks for multidimensional array input (Bruce Momjian)
Previously, an input array string that started with a single-element sub-array could later contain multi-element sub-arrays, e.g. '{{1}, {2,3}}'::int[] would be accepted.
When converting values of type date, timestamp or timestamptz to JSON, render the values in a format compliant with ISO 8601 (Andrew Dunstan)
Previously such values were rendered according to the current datestyle setting; but many JSON processors require timestamps to be in ISO 8601 format. If necessary, the previous behavior can be obtained by explicitly casting the datetime value to text before passing it to the JSON conversion function.
The json #> text[] path extraction operator now returns its lefthand input, not NULL, if the array is empty (Tom Lane)
This is consistent with the notion that this represents zero applications of the simple field/element extraction operator ->. Similarly, json #>> text[] with an empty array merely coerces its lefthand input to text.
Corner cases in the JSON field/element/path extraction operators now return NULL rather than raising an error (Tom Lane)
For example, applying field extraction to a JSON array now yields NULL not an error. This is more consistent (since some comparable cases such as no-such-field already returned NULL), and it makes it safe to create expression indexes that use these operators, since they will now not throw errors for any valid JSON input.
Cause consecutive whitespace in to_timestamp() and to_date() format strings to consume a corresponding number of characters in the input string (whitespace or not), then conditionally consume adjacent whitespace, if not in FX mode (Jeevan Chalke)
Previously, consecutive whitespace characters in a non-FX format string behaved like a single whitespace character and consumed all adjacent whitespace in the input string. For example, previously a format string of three spaces would consume only the first space in ' 12', but it will now consume all three characters.
Fix ts_rank_cd() to ignore stripped lexemes (Alex Hill)
Previously, stripped lexemes were treated as if they had a default location, producing a rank of dubious usefulness.
For functions declared to take VARIADIC "any", an actual parameter marked as VARIADIC must be of a determinable array type (Pavel Stehule)
Such parameters can no longer be written as an undecorated string literal or NULL; a cast to an appropriate array data type will now be required. Note that this does not affect parameters not marked VARIADIC.
Ensure that whole-row variables expose the expected column names to functions that pay attention to column names within composite arguments (Tom Lane)
Constructs like row_to_json(tab.*) now always emit column names that match the column aliases visible for table tab at the point of the call. In previous releases the emitted column names would sometimes be the table's actual column names regardless of any aliases assigned in the query.
DISCARD(7) now also discards sequence-related state (Fabrízio de Royes Mello, Robert Haas)
Rename EXPLAIN ANALYZE's « total runtime » output to « execution time » (Tom Lane)
Now that planning time is also reported, the previous name was confusing.
SHOW TIME ZONE now outputs simple numeric UTC offsets in POSIX timezone format (Tom Lane)
Previously, such timezone settings were displayed as interval values. The new output is properly interpreted by SET TIME ZONE when passed as a simple string, whereas the old output required special treatment to be re-parsed correctly.
Foreign data wrappers that support updating foreign tables must consider the possible presence of AFTER ROW triggers (Noah Misch)
When an AFTER ROW trigger is present, all columns of the table must be returned by updating actions, since the trigger might inspect any or all of them. Previously, foreign tables never had triggers, so the FDW might optimize away fetching columns not mentioned in the RETURNING clause (if any).
Prevent CHECK constraints from referencing system columns, except tableoid (Amit Kapila)
Previously such check constraints were allowed, but they would often cause errors during restores.
Use the last specified recovery target parameter if multiple target parameters are specified (Heikki Linnakangas)
Previously, there was an undocumented precedence order among the recovery_target_xxx parameters.
On Windows, automatically preserve quotes in command strings supplied by the user (Heikki Linnakangas)
User commands that did their own quote preservation might need adjustment. This is likely to be an issue for commands used in archive_command, restore_command, and COPY TO/FROM PROGRAM.
Remove catalog column pg_class.reltoastidxid (Michael Paquier)
Remove catalog column pg_rewrite.ev_attr (Kevin Grittner)
Per-column rules have not been supported since PostgreSQL 7.3.
Remove native support for Kerberos authentication (--with-krb5, etc) (Magnus Hagander)
The supported way to use Kerberos authentication is with GSSAPI. The native code has been deprecated since PostgreSQL™ 8.3.
In PL/Python, handle domains over arrays like the underlying array type (Rodolfo Campero)
Previously such values were treated as strings.
Make libpq's PQconnectdbParams() and PQpingParams() functions process zero-length strings as defaults (Adrian Vondendriesch)
Previously, these functions treated zero-length string values as selecting the default in only some cases.
Change empty arrays returned by the intarray module to be zero-dimensional arrays (Bruce Momjian)
Previously, empty arrays were returned as zero-length one-dimensional arrays, whose text representation looked the same as zero-dimensional arrays ({}), but they acted differently in array operations. intarray's behavior in this area now matches the built-in array operators.
pg_upgrade(1) now uses -U or --username to specify the user name (Bruce Momjian)
Previously this option was spelled -u or --user, but that was inconsistent with other tools.
Below you will find a detailed account of the changes between PostgreSQL™ 9.4 and the previous major release.
Allow background worker processes to be dynamically registered, started and terminated (Robert Haas)
The new worker_spi module shows an example of use of this feature.
Allow dynamic allocation of shared memory segments (Robert Haas, Amit Kapila)
This feature is illustrated in the test_shm_mq module.
During crash recovery or immediate shutdown, send uncatchable termination signals (SIGKILL) to child processes that do not shut down promptly (MauMau, Álvaro Herrera)
This reduces the likelihood of leaving orphaned child processes behind after postmaster(1) shutdown, as well as ensuring that crash recovery can proceed if some child processes have become « stuck ».
Improve randomness of the database system identifier (Tom Lane)
Make VACUUM(7) properly report dead but not-yet-removable rows to the statistics collector (Hari Babu)
Previously these were reported as live rows.
Reduce GIN index size (Alexander Korotkov, Heikki Linnakangas)
Indexes upgraded via pg_upgrade(1) will work fine but will still be in the old, larger GIN format. Use REINDEX(7) to recreate old GIN indexes in the new format.
Improve speed of multi-key GIN lookups (Alexander Korotkov, Heikki Linnakangas)
Add GiST index support for inet and cidr data types (Emre Hasegeli)
Such indexes improve subnet and supernet lookups and ordering comparisons.
Fix rare race condition in B-tree page deletion (Heikki Linnakangas)
Make the handling of interrupted B-tree page splits more robust (Heikki Linnakangas)
Allow multiple backends to insert into WAL buffers concurrently (Heikki Linnakangas)
This improves parallel write performance.
Conditionally write only the modified portion of updated rows to WAL (Amit Kapila)
Improve performance of aggregate functions used as window functions (David Rowley, Florian Pflug, Tom Lane)
Improve speed of aggregates that use numeric state values (Hadi Moshayedi)
Attempt to freeze tuples when tables are rewritten with CLUSTER(7) or VACUUM FULL (Robert Haas, Andres Freund)
This can avoid the need to freeze the tuples in the future.
Improve speed of COPY(7) with default nextval() columns (Simon Riggs)
Improve speed of accessing many different sequences in the same session (David Rowley)
Raise hard limit on the number of tuples held in memory during sorting and B-tree index builds (Noah Misch)
Reduce memory allocated by PL/pgSQL DO(7) blocks (Tom Lane)
Make the planner more aggressive about extracting restriction clauses from mixed AND/OR clauses (Tom Lane)
Disallow pushing volatile WHERE clauses down into DISTINCT subqueries (Tom Lane)
Pushing down a WHERE clause can produce a more efficient plan overall, but at the cost of evaluating the clause more often than is implied by the text of the query; so don't do it if the clause contains any volatile functions.
Auto-resize the catalog caches (Heikki Linnakangas)
This reduces memory consumption for sessions accessing only a few tables, and improves performance for sessions accessing many tables.
Add pg_stat_archiver system view to report WAL archiver activity (Gabriele Bartolini)
Add n_mod_since_analyze columns to pg_stat_all_tables and related system views (Mark Kirkwood)
These columns expose the system's estimate of the number of changed tuples since the table's last ANALYZE(7). This estimate drives decisions about when to auto-analyze.
Add backend_xid and backend_xmin columns to the system view pg_stat_activity, and a backend_xmin column to pg_stat_replication (Christian Kruse)
Add support for SSL ECDH key exchange (Marko Kreen)
This allows use of Elliptic Curve keys for server authentication. Such keys are faster and have better security than RSA keys. The new configuration parameter ssl_ecdh_curve controls which curve is used for ECDH.
Improve the default ssl_ciphers setting (Marko Kreen)
By default, the server not the client now controls the preference order of SSL ciphers (Marko Kreen)
Previously, the order specified by ssl_ciphers was usually ignored in favor of client-side defaults, which are not configurable in most PostgreSQL™ clients. If desired, the old behavior can be restored via the new configuration parameter ssl_prefer_server_ciphers.
Make log_connections show SSL encryption information (Andreas Kunert)
Improve SSL renegotiation handling (Álvaro Herrera)
Add new SQL command ALTER SYSTEM(7) for changing postgresql.conf configuration file entries (Amit Kapila)
Previously such settings could only be changed by manually editing postgresql.conf.
Add autovacuum_work_mem configuration parameter to control the amount of memory used by autovacuum workers (Peter Geoghegan)
Add huge_pages parameter to allow using huge memory pages on Linux (Christian Kruse, Richard Poole, Abhijit Menon-Sen)
This can improve performance on large-memory systems.
Add max_worker_processes parameter to limit the number of background workers (Robert Haas)
This is helpful in configuring a standby server to have the required number of worker processes (the same as the primary).
Add superuser-only session_preload_libraries parameter to load libraries at session start (Peter Eisentraut)
In contrast to local_preload_libraries, this parameter can load any shared library, not just those in the $libdir/plugins directory.
Add wal_log_hints parameter to enable WAL logging of hint-bit changes (Sawada Masahiko)
Hint bit changes are not normally logged, except when checksums are enabled. This is useful for external tools like pg_rewind.
Increase the default settings of work_mem and maintenance_work_mem by four times (Bruce Momjian)
The new defaults are 4MB and 64MB respectively.
Increase the default setting of effective_cache_size to 4GB (Bruce Momjian, Tom Lane)
Allow printf-style space padding to be specified in log_line_prefix (David Rowley)
Allow terabyte units (TB) to be used when specifying configuration variable values (Simon Riggs)
Show PIDs of lock holders and waiters and improve information about relations in log_lock_waits log messages (Christian Kruse)
Reduce server logging level when loading shared libraries (Peter Geoghegan)
The previous level was LOG, which was too verbose for libraries loaded per-session.
On Windows, make SQL_ASCII-encoded databases and server processes (e.g., postmaster(1)) emit messages in the character encoding of the server's Windows user locale (Alexander Law, Noah Misch)
Previously these messages were output in the Windows ANSI code page.
Add replication slots to coordinate activity on streaming standbys with the node they are streaming from (Andres Freund, Robert Haas)
Replication slots allow preservation of resources like WAL files on the primary until they are no longer needed by standby servers.
Add recovery parameter recovery_min_apply_delay to delay replication (Robert Haas, Fabrízio de Royes Mello, Simon Riggs)
Delaying replay on standby servers can be useful for recovering from user errors.
Add recovery_target option immediate to stop WAL recovery as soon as a consistent state is reached (MauMau, Heikki Linnakangas)
Improve recovery target processing (Heikki Linnakangas)
The timestamp reported by pg_last_xact_replay_timestamp() now reflects already-committed records, not transactions about to be committed. Recovering to a restore point now replays the restore point, rather than stopping just before the restore point.
pg_switch_xlog() now clears any unused trailing space in the old WAL file (Heikki Linnakangas)
This improves the compression ratio for WAL files.
Report failure return codes from external recovery commands (Peter Eisentraut)
Reduce spinlock contention during WAL replay (Heikki Linnakangas)
Write WAL records of running transactions more frequently (Andres Freund)
This allows standby servers to start faster and clean up resources more aggressively.
Logical decoding allows database changes to be streamed in a configurable format. The data is read from the WAL and transformed into the desired target format. To implement this feature, the following changes were made:
Add support for logical decoding of WAL data, to allow database changes to be streamed out in a customizable format (Andres Freund)
Add new wal_level setting logical to enable logical change-set encoding in WAL (Andres Freund)
Add table-level parameter REPLICA IDENTITY to control logical replication (Andres Freund)
Add relation option user_catalog_table to identify user-created tables involved in logical change-set encoding (Andres Freund)
Add pg_recvlogical(1) application to receive logical-decoding data (Andres Freund)
Add test_decoding module to illustrate logical decoding at the SQL level (Andres Freund)
Add WITH ORDINALITY syntax to number the rows returned from a set-returning function in the FROM clause (Andrew Gierth, David Fetter)
This is particularly useful for functions like unnest().
Add ROWS FROM() syntax to allow horizontal concatenation of set-returning functions in the FROM clause (Andrew Gierth)
Allow SELECT(7) to have an empty target list (Tom Lane)
This was added so that views that select from a table with zero columns can be dumped and restored correctly.
Ensure that SELECT ... FOR UPDATE NOWAIT does not wait in corner cases involving already-concurrently-updated tuples (Craig Ringer and Thomas Munro)
Add DISCARD SEQUENCES command to discard cached sequence-related state (Fabrízio de Royes Mello, Robert Haas)
DISCARD ALL will now also discard such information.
Add FORCE NULL option to COPY FROM, which causes quoted strings matching the specified null string to be converted to NULLs in CSV mode (Ian Barwick, Michael Paquier)
Without this option, only unquoted matching strings will be imported as null values.
Issue warnings for commands used outside of transaction blocks when they can have no effect (Bruce Momjian)
New warnings are issued for SET LOCAL, SET CONSTRAINTS, SET TRANSACTION and ABORT when used outside a transaction block.
Make EXPLAIN ANALYZE show planning time (Andreas Karlsson)
Make EXPLAIN show the grouping columns in Agg and Group nodes (Tom Lane)
Make EXPLAIN ANALYZE show exact and lossy block counts in bitmap heap scans (Etsuro Fujita)
Allow a materialized view to be refreshed without blocking other sessions from reading the view meanwhile (Kevin Grittner)
This is done with REFRESH MATERIALIZED VIEW CONCURRENTLY.
Allow views to be automatically updated even if they contain some non-updatable columns (Dean Rasheed)
Previously the presence of non-updatable output columns such as expressions, literals, and function calls prevented automatic updates. Now INSERTs, UPDATEs and DELETEs are supported, provided that they do not attempt to assign new values to any of the non-updatable columns.
Allow control over whether INSERTs and UPDATEs can add rows to an auto-updatable view that would not appear in the view (Dean Rasheed)
This is controlled with the new CREATE VIEW(7) clause WITH CHECK OPTION.
Allow security barrier views to be automatically updatable (Dean Rasheed)
Support triggers on foreign tables (Ronan Dunklau)
Allow moving groups of objects from one tablespace to another using the ALL IN TABLESPACE ... SET TABLESPACE form of ALTER TABLE(7), ALTER INDEX(7), or ALTER MATERIALIZED VIEW(7) (Stephen Frost)
Allow changing foreign key constraint deferrability via ALTER TABLE(7) ... ALTER CONSTRAINT (Simon Riggs)
Reduce lock strength for some ALTER TABLE(7) commands (Simon Riggs, Noah Misch, Robert Haas)
Specifically, VALIDATE CONSTRAINT, CLUSTER ON, SET WITHOUT CLUSTER, ALTER COLUMN SET STATISTICS, ALTER COLUMN SET (attribute_option), ALTER COLUMN RESET (attribute_option) no longer require ACCESS EXCLUSIVE locks.
Allow tablespace options to be set in CREATE TABLESPACE(7) (Vik Fearing)
Formerly these options could only be set via ALTER TABLESPACE(7).
Allow CREATE AGGREGATE(7) to define the estimated size of the aggregate's transition state data (Hadi Moshayedi)
Proper use of this feature allows the planner to better estimate how much memory will be used by aggregates.
Fix DROP IF EXISTS to avoid errors for non-existent objects in more cases (Pavel Stehule, Dean Rasheed)
Improve how system relations are identified (Andres Freund, Robert Haas)
Previously, relations once moved into the pg_catalog schema could no longer be modified or dropped.
Fully implement the line data type (Peter Eisentraut)
The line segment data type (lseg) has always been fully supported. The previous line data type (which was enabled only via a compile-time option) is not binary or dump-compatible with the new implementation.
Add pg_lsn data type to represent a WAL log sequence number (LSN) (Robert Haas, Michael Paquier)
Allow single-point polygons to be converted to circles (Bruce Momjian)
Support time zone abbreviations that change UTC offset from time to time (Tom Lane)
Previously, PostgreSQL™ assumed that the UTC offset associated with a time zone abbreviation (such as EST) never changes in the usage of any particular locale. However this assumption fails in the real world, so introduce the ability for a zone abbreviation to represent a UTC offset that sometimes changes. Update the zone abbreviation definition files to make use of this feature in timezone locales that have changed the UTC offset of their abbreviations since 1970 (according to the IANA timezone database). In such timezones, PostgreSQL™ will now associate the correct UTC offset with the abbreviation depending on the given date.
Allow 5+ digit years for non-ISO timestamp and date strings, where appropriate (Bruce Momjian)
Add checks for overflow/underflow of interval values (Bruce Momjian)
Add jsonb, a more capable and efficient data type for storing JSON data (Oleg Bartunov, Teodor Sigaev, Alexander Korotkov, Peter Geoghegan, Andrew Dunstan)
This new type allows faster access to values within a JSON document, and faster and more useful indexing of JSON columns. Scalar values in jsonb documents are stored as appropriate scalar SQL types, and the JSON document structure is pre-parsed rather than being stored as text as in the original json data type.
Add new JSON functions to allow for the construction of arbitrarily complex JSON trees (Andrew Dunstan, Laurence Rowe)
New functions include json_array_elements_text(), json_build_array(), json_object(), json_object_agg(), json_to_record(), and json_to_recordset().
Add json_typeof() to return the data type of a json value (Andrew Tipton)
Add pg_sleep_for(interval) and pg_sleep_until(timestamp) to specify delays more flexibly (Vik Fearing, Julien Rouhaud)
The existing pg_sleep() function only supports delays specified in seconds.
Add cardinality() function for arrays (Marko Tiikkaja)
This returns the total number of elements in the array, or zero for an array with no elements.
Add SQL functions to allow large object reads/writes at arbitrary offsets (Pavel Stehule)
Allow unnest() to take multiple arguments, which are individually unnested then horizontally concatenated (Andrew Gierth)
Add functions to construct times, dates, timestamps, timestamptzs, and intervals from individual values, rather than strings (Pavel Stehule)
These functions' names are prefixed with make_, e.g. make_date().
Make to_char()'s TZ format specifier return a useful value for simple numeric time zone offsets (Tom Lane)
Previously, to_char(CURRENT_TIMESTAMP, 'TZ') returned an empty string if the timezone was set to a constant like -4.
Add timezone offset format specifier OF to to_char() (Bruce Momjian)
Improve the random seed used for random() (Honza Horak)
Tighten validity checking for Unicode code points in chr(int) (Tom Lane)
This function now only accepts values that are valid UTF8 characters according to RFC 3629.
Add functions for looking up objects in pg_class, pg_proc, pg_type, and pg_operator that do not generate errors for non-existent objects (Yugo Nagata, Nozomi Anzai, Robert Haas)
For example, to_regclass() does a lookup in pg_class similarly to the regclass input function, but it returns NULL for a non-existent object instead of failing.
Add function pg_filenode_relation() to allow for more efficient lookup of relation names from filenodes (Andres Freund)
Add parameter_default column to information_schema.parameters view (Peter Eisentraut)
Make information_schema.schemata show all accessible schemas (Peter Eisentraut)
Previously it only showed schemas owned by the current user.
Add control over which rows are passed into aggregate functions via the FILTER clause (David Fetter)
Support ordered-set (WITHIN GROUP) aggregates (Atri Sharma, Andrew Gierth, Tom Lane)
Add standard ordered-set aggregates percentile_cont(), percentile_disc(), mode(), rank(), dense_rank(), percent_rank(), and cume_dist() (Atri Sharma, Andrew Gierth)
Support VARIADIC aggregate functions (Tom Lane)
Allow polymorphic aggregates to have non-polymorphic state data types (Tom Lane)
This allows proper declaration in SQL of aggregates like the built-in aggregate array_agg().
Add ability to retrieve the current PL/pgSQL call stack using GET DIAGNOSTICS (Pavel Stehule, Stephen Frost)
Add option print_strict_params to display the parameters passed to a query that violated a STRICT constraint (Marko Tiikkaja)
Add variables plpgsql.extra_warnings and plpgsql.extra_errors to enable additional PL/pgSQL warnings and errors (Marko Tiikkaja, Petr Jelinek)
Currently only warnings/errors about shadowed variables are available.
Make libpq's PQconndefaults() function ignore invalid service files (Steve Singer, Bruce Momjian)
Previously it returned NULL if an incorrect service file was encountered.
Accept TLS protocol versions beyond TLSv1 in libpq (Marko Kreen)
Add createuser(1) option -g to specify role membership (Christopher Browne)
Add vacuumdb(1) option --analyze-in-stages to analyze in stages of increasing granularity (Peter Eisentraut)
This allows minimal statistics to be created quickly.
Make pg_resetxlog with option -n output current and potentially changed values (Rajeev Rastogi)
Make initdb(1) throw error for incorrect locale settings, rather than silently falling back to a default choice (Tom Lane)
Make pg_ctl(1) return exit code 4 for an inaccessible data directory (Amit Kapila, Bruce Momjian)
This behavior more closely matches the Linux Standard Base (LSB) Core Specification.
On Windows, ensure that a non-absolute -D path specification is interpreted relative to pg_ctl(1)'s current directory (Kumar Rajeev Rastogi)
Previously it would be interpreted relative to whichever directory the underlying Windows service was started in.
Allow sizeof() in ECPG C array definitions (Michael Meskes)
Make ECPG properly handle nesting of C-style comments in both C and SQL text (Michael Meskes)
Suppress « No rows » output in psql expanded mode when the footer is disabled (Bruce Momjian)
Allow Control-C to abort psql when it's hung at connection startup (Peter Eisentraut)
Make psql's \db+ show tablespace options (Magnus Hagander)
Make \do+ display the functions that implement the operators (Marko Tiikkaja)
Make \d+ output an OID line only if an oid column exists in the table (Bruce Momjian)
Previously, the presence or absence of an oid column was always reported.
Make \d show disabled system triggers (Bruce Momjian)
Previously, if you disabled all triggers, only user triggers would show as disabled.
Fix \copy to no longer require a space between stdin and a semicolon (Etsuro Fujita)
Output the row count at the end of \copy, just like COPY already did (Kumar Rajeev Rastogi)
Fix \conninfo to display the server's IP address for connections using hostaddr (Fujii Masao)
Previously \conninfo could not display the server's IP address in such cases.
Show the SSL protocol version in \conninfo (Marko Kreen)
Add tab completion for \pset (Pavel Stehule)
Allow \pset with no arguments to show all settings (Gilles Darold)
Make \s display the name of the history file it wrote without converting it to an absolute path (Tom Lane)
The code previously attempted to convert a relative file name to an absolute path for display, but frequently got it wrong.
Allow pg_restore(1) options -I, -P, -T and -n to be specified multiple times (Heikki Linnakangas)
This allows multiple objects to be restored in one operation.
Optionally add IF EXISTS clauses to the DROP commands emitted when removing old objects during a restore (Pavel Stehule)
This change prevents unnecessary errors when removing old objects. The new --if-exists option for pg_dump(1), pg_dumpall(1), and pg_restore(1) is only available when --clean is also specified.
Add pg_basebackup option --xlogdir to specify the pg_xlog directory location (Haribabu Kommi)
Allow pg_basebackup to relocate tablespaces in the backup copy (Steeve Lennmark)
This is particularly useful for using pg_basebackup on the same machine as the primary.
Allow network-stream base backups to be throttled (Antonin Houska)
This can be controlled with the pg_basebackup --max-rate parameter.
Improve the way tuples are frozen to preserve forensic information (Robert Haas, Andres Freund)
This change removes the main objection to freezing tuples as soon as possible. Code that inspects tuple flag bits will need to be modified.
No longer require function prototypes for functions marked with the PG_FUNCTION_INFO_V1 macro (Peter Eisentraut)
This change eliminates the need to write boilerplate prototypes. Note that the PG_FUNCTION_INFO_V1 macro must appear before the corresponding function definition to avoid compiler warnings.
Remove SnapshotNow and HeapTupleSatisfiesNow() (Robert Haas)
All existing uses have been switched to more appropriate snapshot types. Catalog scans now use MVCC snapshots.
Add an API to allow memory allocations over one gigabyte (Noah Misch)
Add psprintf() to simplify memory allocation during string composition (Peter Eisentraut, Tom Lane)
Support printf() size modifier z to print size_t values (Andres Freund)
Change API of appendStringInfoVA() to better use vsnprintf() (David Rowley, Tom Lane)
Allow new types of external toast datums to be created (Andres Freund)
Add single-reader, single-writer, lightweight shared message queue (Robert Haas)
Improve spinlock speed on x86_64 CPUs (Heikki Linnakangas)
Remove spinlock support for unsupported platforms SINIX™, Sun3™, and NS32K™ (Robert Haas)
Remove IRIX port (Robert Haas)
Reduce the number of semaphores required by --disable-spinlocks builds (Robert Haas)
Rewrite duplicate_oids Unix shell script in Perl (Andrew Dunstan)
Add Test Anything Protocol (TAP) tests for client programs (Peter Eisentraut)
Currently, these tests are run by make check-world only if the --enable-tap-tests option was given to configure. This might become the default behavior in some future release.
Add make targets check-tests and installcheck-tests, which allow selection of individual tests to be run (Andrew Dunstan)
Remove maintainer-check makefile rule (Peter Eisentraut)
The default build rules now include all the formerly-optional tests.
Improve support for VPATH builds of PGXS modules (Cédric Villemain, Andrew Dunstan, Peter Eisentraut)
Upgrade to Autoconf 2.69 (Peter Eisentraut)
Add a configure flag that appends custom text to the PG_VERSION string (Oskari Saarenmaa)
This is useful for packagers building custom binaries.
Improve DocBook XML validity (Peter Eisentraut)
Fix various minor security and sanity issues reported by the Coverity™ scanner (Stephen Frost)
Improve detection of invalid memory usage when testing PostgreSQL™ with Valgrind (Noah Misch)
Improve sample Emacs configuration file emacs.samples (Peter Eisentraut)
Also add .dir-locals.el to the top of the source tree.
Allow pgindent to accept a command-line list of typedefs (Bruce Momjian)
Make pgindent smarter about blank lines around preprocessor conditionals (Bruce Momjian)
Avoid most uses of dlltool in Cygwin™ and Mingw™ builds (Marco Atzeri, Hiroshi Inoue)
Support client-only installs in MSVC (Windows) builds (MauMau)
Add pg_prewarm extension to preload relation data into the shared buffer cache at server start (Robert Haas)
This allows reaching full operating performance more quickly.
Add UUID random number generator gen_random_uuid() to pgcrypto (Oskari Saarenmaa)
This allows creation of version 4 UUIDs without requiring installation of uuid-ossp.
Allow uuid-ossp to work with the BSD or e2fsprogs UUID libraries, not only the OSSP UUID library (Matteo Beccati)
This improves the uuid-ossp module's portability since it no longer has to have the increasingly-obsolete OSSP library. The module's name is now rather a misnomer, but we won't change it.
Add option to auto_explain to include trigger execution time (Horiguchi Kyotaro)
Fix pgstattuple to not report rows from uncommitted transactions as dead (Robert Haas)
Make pgstattuple functions use regclass-type arguments (Satoshi Nagayasu)
While text-type arguments are still supported, they may be removed in a future major release.
Improve consistency of pgrowlocks output to honor snapshot rules more consistently (Robert Haas)
Improve pg_trgm's choice of trigrams for indexed regular expression searches (Alexander Korotkov)
This change discourages use of trigrams containing whitespace, which are usually less selective.
Allow pg_xlogdump to report a live log stream with --follow (Heikki Linnakangas)
Store cube data more compactly (Stas Kelvich)
Existing data must be dumped/restored to use the new format. The old format can still be read.
Reduce vacuumlo(1) client-side memory usage by using a cursor (Andrew Dunstan)
Dramatically reduce memory consumption in pg_upgrade(1) (Bruce Momjian)
Pass pg_upgrade(1)'s user name (-U) option to generated analyze scripts (Bruce Momjian)
Remove line length limit for pgbench scripts (Sawada Masahiko)
The previous line limit was BUFSIZ.
Add long option names to pgbench (Fabien Coelho)
Add pgbench option --rate to control the transaction rate (Fabien Coelho)
Add pgbench option --progress to print periodic progress reports (Fabien Coelho)
Make pg_stat_statements use a file, rather than shared memory, for query text storage (Peter Geoghegan)
This removes the previous limitation on query text length, and allows a higher number of unique statements to be tracked by default.
Allow reporting of pg_stat_statements's internal query hash identifier (Daniel Farina, Sameer Thakur, Peter Geoghegan)
Add the ability to retrieve all pg_stat_statements information except the query text (Peter Geoghegan)
This allows monitoring tools to fetch query text only for just-created entries, improving performance during repeated querying of the statistics.
Make pg_stat_statements ignore DEALLOCATE commands (Fabien Coelho)
It already ignored PREPARE, as well as planning time in general, so this seems more consistent.
Save the statistics file into $PGDATA/pg_stat at server shutdown, rather than $PGDATA/global (Fujii Masao)
Release 9.4.1
