DocumentationVersion comparison
POSTGRESQL · VERSION COMPARE
All features, fixes, and compatibility notes in this release, with related records from other versions.
Includes changes after the source version through the target. A major version name means its initial release.
From PostgreSQL 9.0 onward: 17 major branches and 352 release notes. Updated 2026-09-26.
Complete release changes
2015-10-08
9.1.19 HistoricalSupport ends 2016-10-27
| CVE / issue | Severity | Fixed version |
|---|---|---|
| CVE-2015-5288 Fix contrib/pgcrypto to detect and report too-short crypt() salts | 3.1 | 9.1.19 |
A dump/restore is not required for those running 9.1.X.
However, if you are upgrading from a version earlier than 9.1.16, see Section E.9.
Changes
Fix contrib/pgcrypto to detect and report too-short crypt() salts (Josh Kupershmidt)
Certain invalid salt arguments crashed the server or disclosed a few bytes of server memory. We have not ruled out the viability of attacks that arrange for presence of confidential information in the disclosed bytes, but they seem unlikely. (CVE-2015-5288)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix subtransaction cleanup after a portal (cursor) belonging to an outer subtransaction fails (Tom Lane, Michael Paquier)
A function executed in an outer-subtransaction cursor could cause an assertion failure or crash by referencing a relation created within an inner subtransaction.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix insertion of relations into the relation cache "init file" (Tom Lane)
An oversight in a patch in the most recent minor releases caused pg_trigger_tgrelid_tgname_index to be omitted from the init file. Subsequent sessions detected this, then deemed the init file to be broken and silently ignored it, resulting in a significant degradation in session startup time. In addition to fixing the bug, install some guards so that any similar future mistake will be more obvious.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Avoid O(N^2) behavior when inserting many tuples into a SPI query result (Neil Conway)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Improve LISTEN startup time when there are many unread notifications (Matt Newell)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Back-patch 9.3-era addition of per-resource-owner lock caches (Jeff Janes)
This substantially improves performance when pg_dump tries to dump a large number of tables.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Disable SSL renegotiation by default (Michael Paquier, Andres Freund)
While use of SSL renegotiation is a good idea in theory, we have seen too many bugs in practice, both in the underlying OpenSSL library and in our usage of it. Renegotiation will be removed entirely in 9.5 and later. In the older branches, just change the default value of ssl_renegotiation_limit to zero (disabled).
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Lower the minimum values of the *_freeze_max_age parameters (Andres Freund)
This is mainly to make tests of related behavior less time-consuming, but it may also be of value for installations with limited disk space.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Limit the maximum value of wal_buffers to 2GB to avoid server crashes (Josh Berkus)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix rare internal overflow in multiplication of numeric values (Dean Rasheed)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Guard against hard-to-reach stack overflows involving record types, range types, json, jsonb, tsquery, ltxtquery and query_int (Noah Misch)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix handling of DOW and DOY in datetime input (Greg Stark)
These tokens aren't meant to be used in datetime values, but previously they resulted in opaque internal error messages rather than "invalid input syntax".
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Add more query-cancel checks to regular expression matching (Tom Lane)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Add recursion depth protections to regular expression, SIMILAR TO, and LIKE matching (Tom Lane)
Suitable search patterns and a low stack depth limit could lead to stack-overrun crashes.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix potential infinite loop in regular expression execution (Tom Lane)
A search pattern that can apparently match a zero-length string, but actually doesn't match because of a back reference, could lead to an infinite loop.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix low-memory failures in regular expression compilation (Andreas Seltenreich)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix low-probability memory leak during regular expression execution (Tom Lane)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix rare low-memory failure in lock cleanup during transaction abort (Tom Lane)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix "unexpected out-of-memory situation during sort" errors when using tuplestores with small work_mem settings (Tom Lane)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix very-low-probability stack overrun in qsort (Tom Lane)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix "invalid memory alloc request size" failure in hash joins with large work_mem settings (Tomas Vondra, Tom Lane)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix assorted planner bugs (Tom Lane)
These mistakes could lead to incorrect query plans that would give wrong answers, or to assertion failures in assert-enabled builds, or to odd planner errors such as "could not devise a query plan for the given query", "could not find pathkey item to sort", "plan should not reference subplan's variable", or "failed to assign all NestLoopParams to plan nodes". Thanks are due to Andreas Seltenreich and Piotr Stefaniak for fuzz testing that exposed these problems.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Use fuzzy path cost tiebreaking rule in all supported branches (Tom Lane)
This change is meant to avoid platform-specific behavior when alternative plan choices have effectively-identical estimated costs.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Ensure standby promotion trigger files are removed at postmaster startup (Michael Paquier, Fujii Masao)
This prevents unwanted promotion from occurring if these files appear in a database backup that is used to initialize a new standby server.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
During postmaster shutdown, ensure that per-socket lock files are removed and listen sockets are closed before we remove the postmaster.pid file (Tom Lane)
This avoids race-condition failures if an external script attempts to start a new postmaster as soon as pg_ctl stop returns.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix postmaster's handling of a startup-process crash during crash recovery (Tom Lane)
If, during a crash recovery cycle, the startup process crashes without having restored database consistency, we'd try to launch a new startup process, which typically would just crash again, leading to an infinite loop.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Do not print a WARNING when an autovacuum worker is already gone when we attempt to signal it, and reduce log verbosity for such signals (Tom Lane)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Prevent autovacuum launcher from sleeping unduly long if the server clock is moved backwards a large amount (Álvaro Herrera)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Ensure that cleanup of a GIN index's pending-insertions list is interruptable by cancel requests (Jeff Janes)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Allow all-zeroes pages in GIN indexes to be reused (Heikki Linnakangas)
Such a page might be left behind after a crash.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix off-by-one error that led to otherwise-harmless warnings about "apparent wraparound" in subtrans/multixact truncation (Thomas Munro)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix misreporting of CONTINUE and MOVE statement types in PL/pgSQL's error context messages (Pavel Stehule, Tom Lane)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix PL/Perl to handle non-ASCII error message texts correctly (Alex Hunsaker)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix PL/Python crash when returning the string representation of a record result (Tom Lane)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix some places in PL/Tcl that neglected to check for failure of malloc() calls (Michael Paquier, Álvaro Herrera)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
In contrib/isn, fix output of ISBN-13 numbers that begin with 979 (Fabien Coelho)
EANs beginning with 979 (but not 9790) are considered ISBNs, but they must be printed in the new 13-digit format, not the 10-digit format.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Improve libpq's handling of out-of-memory conditions (Michael Paquier, Heikki Linnakangas)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix memory leaks and missing out-of-memory checks in ecpg (Michael Paquier)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix psql's code for locale-aware formatting of numeric output (Tom Lane)
The formatting code invoked by \pset numericlocale on did the wrong thing for some uncommon cases such as numbers with an exponent but no decimal point. It could also mangle already-localized output from the money data type.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Prevent crash in psql's \c command when there is no current connection (Noah Misch)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix selection of default zlib compression level in pg_dump's directory output format (Andrew Dunstan)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Ensure that temporary files created during a pg_dump run with tar-format output are not world-readable (Michael Paquier)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix pg_dump and pg_upgrade to support cases where the postgres or template1 database is in a non-default tablespace (Marti Raudsepp, Bruce Momjian)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix pg_dump to handle object privileges sanely when dumping from a server too old to have a particular privilege type (Tom Lane)
When dumping functions or procedural languages from pre-7.3 servers, pg_dump would produce GRANT/REVOKE commands that revoked the owner's grantable privileges and instead granted all privileges to PUBLIC. Since the privileges involved are just USAGE and EXECUTE, this isn't a security problem, but it's certainly a surprising representation of the older systems' behavior. Fix it to leave the default privilege state alone in these cases.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix pg_dump to dump shell types (Tom Lane)
Shell types (that is, not-yet-fully-defined types) aren't useful for much, but nonetheless pg_dump should dump them.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix assorted minor memory leaks in pg_dump and other client-side programs (Michael Paquier)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix spinlock assembly code for PPC hardware to be compatible with AIX's native assembler (Tom Lane)
Building with gcc didn't work if gcc had been configured to use the native assembler, which is becoming more common.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
On AIX, test the -qlonglong compiler option rather than just assuming it's safe to use (Noah Misch)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
On AIX, use -Wl,-brtllib link option to allow symbols to be resolved at runtime (Noah Misch)
Perl relies on this ability in 5.8.0 and later.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Avoid use of inline functions when compiling with 32-bit xlc, due to compiler bugs (Noah Misch)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Use librt for sched_yield() when necessary, which it is on some Solaris versions (Oskari Saarenmaa)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Fix Windows install.bat script to handle target directory names that contain spaces (Heikki Linnakangas)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Make the numeric form of the PostgreSQL version number (e.g., 90405) readily available to extension Makefiles, as a variable named VERSION_NUM (Michael Paquier)
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
Changes
Update time zone data files to tzdata release 2015g for DST law changes in Cayman Islands, Fiji, Moldova, Morocco, Norfolk Island, North Korea, Turkey, and Uruguay. There is a new zone name America/Fort_Nelson for the Canadian Northern Rockies.
“Same change” requires complete matching evidence. “Related commits” can cover independent changes, a partial backport, or a follow-up correction; each release keeps its own explanation.
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The comparison follows PostgreSQL release notes from just after the source through the target version. For a major upgrade, maintenance releases from each older branch are included only up to the next major release date, and never after the target date. A major version such as 18 means its initial release, 18.0. Previews and development snapshots are labeled separately.
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Fixes can be backported to several branches. Confirmed duplicates are merged conservatively, with every branch explanation retained. A note describing several independent fixes is excluded only when all are already present in the source. Major-release features remain distinct from related maintenance patches unless their complete original descriptions match. Uncertain matches are retained. This is a release-note history, not an exhaustive comparison of compiled binaries.
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