Release date: 2014-12-18
Major enhancements in PostgreSQL 9.4 include:
jsonb, a more
capable and efficient data type for storing JSON data
Add new SQL command ALTER SYSTEM
configuration file entries
Reduce lock strength for some ALTER TABLE 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.
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
would be accepted.
When converting values of type
JSON, render the values in a format compliant
with ISO 8601 (Andrew Dunstan)
Previously such values were rendered according to the current
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
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
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_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
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
ts_rank_cd() to ignore stripped lexemes (Alex
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
Ensure that whole-row variables expose the expected column names to functions that pay attention to column names within composite arguments (Tom Lane)
now always emit column names that match the column aliases visible
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 now also discards sequence-related state (Fabrízio de Royes Mello, Robert Haas)
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
Previously, such timezone settings were displayed as
interval values. The new output is properly
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
ROW triggers (Noah Misch)
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).
CHECK constraints from referencing system
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
On Windows, automatically preserve quotes in command strings supplied by the user (Heikki Linnakangas)
Remove catalog column
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.
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 (
they acted differently in array operations. intarray's behavior in this area now matches
the built-in array operators.
pg_upgrade now uses
specify the user name (Bruce Momjian)
Previously this option was spelled
--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)
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
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 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 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)
Improve speed of multi-key GIN lookups (Alexander Korotkov, Heikki Linnakangas)
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
state values (Hadi Moshayedi)
This can avoid the need to freeze the tuples in the future.
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 blocks (Tom Lane)
Make the planner more aggressive about extracting restriction
clauses from mixed
OR clauses (Tom Lane)
Disallow pushing volatile
clauses down into
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
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.
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. This estimate drives decisions about when to auto-analyze.
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
configuration file entries (Amit Kapila)
Previously such settings could only be changed by manually
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
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.
The new defaults are 4MB and 64MB respectively.
Increase the default setting of effective_cache_size to 4GB (Bruce Momjian, Tom Lane)
printf-style space padding
to be specified in log_line_prefix
Allow terabyte units (
TB) to be
used when specifying configuration variable values (Simon
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
was too verbose for libraries loaded per-session.
On Windows, make
databases and server processes (e.g., postmaster) 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.
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
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 application to receive logical-decoding data (Andres Freund)
Add test_decoding module to illustrate logical decoding at the SQL level (Andres Freund)
ORDINALITY syntax to number the rows returned from a
set-returning function in the
clause (Andrew Gierth, David Fetter)
This is particularly useful for functions like
FROM() syntax to allow horizontal concatenation of
set-returning functions in the
clause (Andrew Gierth)
Allow SELECT 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.
SELECT ... FOR UPDATE
NOWAIT does not wait in corner cases involving
already-concurrently-updated tuples (Craig Ringer and Thomas
command to discard cached sequence-related state (Fabrízio de Royes
Mello, Robert Haas)
DISCARD ALL will now also discard
FORCE NULL option to
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 TRANSACTION and
ABORT when used outside a transaction block.
EXPLAIN ANALYZE show planning
time (Andreas Karlsson)
EXPLAIN show the grouping
columns in Agg and Group nodes (Tom Lane)
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
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
are supported, provided that they do not attempt to assign new
values to any of the non-updatable columns.
Allow control over whether
UPDATEs can add rows to an
auto-updatable view that would not appear in the view (Dean
This is controlled with the new CREATE VIEW clause
WITH CHECK OPTION.
Allow security barrier views to be automatically updatable (Dean Rasheed)
Support triggers on foreign tables (Ronan Dunklau)
Allow changing foreign key constraint deferrability via
ALTER CONSTRAINT (Simon Riggs)
Reduce lock strength for some ALTER TABLE commands (Simon Riggs, Noah Misch, Robert Haas)
ALTER COLUMN SET
no longer require
Allow tablespace options to be set in CREATE TABLESPACE (Vik Fearing)
Formerly these options could only be set via ALTER TABLESPACE.
Allow CREATE AGGREGATE 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.
DROP IF EXISTS to avoid errors
for non-existent objects in more cases (Pavel Stehule, Dean
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
Fully implement the
line data type
The line segment data
lseg) has always been fully supported. The
line data type (which was
enabled only via a compile-time option) is not binary or
dump-compatible with the new implementation.
type to represent a WAL log
sequence number (LSN) (Robert
Haas, Michael Paquier)
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
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
date strings, where appropriate
Add checks for overflow/underflow of
values (Bruce Momjian)
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
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_typeof() to return the data type of a
json value (Andrew Tipton)
pg_sleep_until(timestamp) to specify delays more
flexibly (Vik Fearing, Julien Rouhaud)
only supports delays specified in seconds.
cardinality() function for arrays (Marko
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)
unnest() to take multiple arguments, which
are individually unnested then horizontally concatenated (Andrew
Add functions to construct
intervals from individual values,
rather than strings (Pavel Stehule)
These functions' names are prefixed with
format specifier return a useful value for simple numeric time zone
offsets (Tom Lane)
'TZ') returned an empty string if the
timezone was set to a constant like
Add timezone offset format specifier
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_operator that do not generate errors for
non-existent objects (Yugo Nagata, Nozomi Anzai, Robert Haas)
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.
pg_filenode_relation() to allow for more efficient
lookup of relation names from filenodes (Andres Freund)
parameter_default column to
information_schema.parameters view (Peter
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
FILTER clause (David Fetter)
Support ordered-set (
GROUP) aggregates (Atri Sharma, Andrew Gierth, Tom
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
Add ability to retrieve the current PL/pgSQL call stack using
GET DIAGNOSTICS (Pavel Stehule, Stephen Frost)
print_strict_params to display the parameters passed to
a query that violated a
constraint (Marko Tiikkaja)
plpgsql.extra_errors to enable additional PL/pgSQL
warnings and errors (Marko Tiikkaja, Petr Jelinek)
Currently only warnings/errors about shadowed variables are available.
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
TLSv1 in libpq (Marko
Add createuser option
-g to specify role membership (Christopher
Add vacuumdb option
--analyze-in-stages to analyze in stages of
increasing granularity (Peter Eisentraut)
This allows minimal statistics to be created quickly.
-n output current and
potentially changed values (Rajeev Rastogi)
Make initdb throw error for incorrect locale settings, rather than silently falling back to a default choice (Tom Lane)
Make pg_ctl 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's current directory (Kumar
Previously it would be interpreted relative to whichever directory the underlying Windows service was started in.
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)
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)
\db+ show tablespace options (Magnus Hagander)
\do+ display the functions
that implement the operators (Marko Tiikkaja)
\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.
\d show disabled system
triggers (Bruce Momjian)
Previously, if you disabled all triggers, only user triggers would show as disabled.
\copy to no longer require a
stdin and a semicolon
Output the row count at the end of
\copy, just like
already did (Kumar Rajeev Rastogi)
\conninfo to display the
server's IP address for
\conninfo could not
display the server's IP address
in such cases.
Show the SSL protocol version
\conninfo (Marko Kreen)
Add tab completion for
\pset with no arguments to
show all settings (Gilles Darold)
\s display the name of the
history file it wrote without converting it to an absolute path
The code previously attempted to convert a relative file name to an absolute path for display, but frequently got it wrong.
-n to be specified multiple times (Heikki
This allows multiple objects to be restored in one operation.
IF EXISTS clauses to
DROP commands emitted when
removing old objects during a restore (Pavel Stehule)
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
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
PG_FUNCTION_INFO_V1 macro (Peter
This change eliminates the need to write boilerplate prototypes.
Note that the
macro must appear before the corresponding function definition to
avoid compiler warnings.
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)
psprintf() to simplify memory
allocation during string composition (Peter Eisentraut, Tom
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
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
installcheck-tests, which allow
selection of individual tests to be run (Andrew Dunstan)
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
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
.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
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
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)
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
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 client-side memory usage by using a cursor (Andrew Dunstan)
Dramatically reduce memory consumption in pg_upgrade (Bruce Momjian)
Pass pg_upgrade'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
Add long option names to pgbench (Fabien Coelho)
Add pgbench option
--rate to control the transaction rate (Fabien
Add pgbench option
--progress to print periodic progress reports
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
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)
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