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
2018-11-08
9.6.11 HistoricalSupport ends 2021-11-11
A dump/restore is not required for those running 9.6.X.
However, if you are upgrading from a version earlier than 9.6.9, see Section E.16.
Changes
Fix corner-case failures in has_foo_privilege() family of functions (Tom Lane)
Return NULL rather than throwing an error when an invalid object OID is provided. Some of these functions got that right already, but not all. has_column_privilege() was additionally capable of crashing on some platforms.
“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) slowdown in regular expression match/split functions on long strings (Andrew Gierth)
“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 parsing of standard multi-character operators that are immediately followed by a comment or + or - (Andrew Gierth)
This oversight could lead to parse errors, or to incorrect assignment of precedence.
“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^3) slowdown in lexer for long strings of + or - characters (Andrew Gierth)
“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 mis-execution of SubPlans when the outer query is being scanned backwards (Andrew Gierth)
“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 failure of UPDATE/DELETE ... WHERE CURRENT OF ... after rewinding the referenced cursor (Tom Lane)
A cursor that scans multiple relations (particularly an inheritance tree) could produce wrong behavior if rewound to an earlier relation.
“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 EvalPlanQual to handle conditionally-executed InitPlans properly (Andrew Gierth, Tom Lane)
This resulted in hard-to-reproduce crashes or wrong answers in concurrent updates, if they contained code such as an uncorrelated sub-SELECT inside a CASE construct.
“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 character-class checks to not fail on Windows for Unicode characters above U+FFFF (Tom Lane, Kenji Uno)
This bug affected full-text-search operations, as well as contrib/ltree and contrib/pg_trgm.
“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
Disallow pushing sub-SELECTs containing window functions, LIMIT, or OFFSET to parallel workers (Amit Kapila)
Such cases could result in inconsistent behavior due to different workers getting different answers, as a result of indeterminacy due to row-ordering variations.
“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 sequences owned by a foreign table are processed by ALTER OWNER on the table (Peter Eisentraut)
The ownership change should propagate to such sequences as well, but this was missed for foreign 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
Ensure that the server will process already-received NOTIFY and SIGTERM interrupts before waiting for client input (Jeff Janes, 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 over-allocation of space for array_out()'s result string (Keiichi Hirobe)
“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 leak in repeated SP-GiST index scans (Tom Lane)
This is only known to amount to anything significant in cases where an exclusion constraint using SP-GiST receives many new index entries in a single command.
“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 ApplyLogicalMappingFile() closes the mapping file when done with it (Tomas Vondra)
Previously, the file descriptor was leaked, eventually resulting in failures during logical decoding.
“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 logical decoding to handle cases where a mapped catalog table is repeatedly rewritten, e.g., by VACUUM FULL (Andres Freund)
“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 starting the server with wal_level set to too low a value to support an existing replication slot (Andres Freund)
“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 crash if a utility command causes infinite recursion (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
When initializing a hot standby, cope with duplicate XIDs caused by two-phase transactions on the master (Michael Paquier, Konstantin Knizhnik)
“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 event triggers to handle nested ALTER TABLE commands (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
Propagate parent process's transaction and statement start timestamps to parallel workers (Konstantin Knizhnik)
This prevents misbehavior of functions such as transaction_timestamp() when executed in a worker.
“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 transfer of expanded datums to parallel workers so that alignment is preserved, preventing crashes on alignment-picky platforms (Tom Lane, Amit Kapila)
“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 WAL file recycling logic to work correctly on standby servers (Michael Paquier)
Depending on the setting of archive_mode, a standby might fail to remove some WAL files that could be removed.
“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 commit-timestamp tracking during recovery (Masahiko Sawada, Michael Paquier)
If commit timestamp tracking has been turned on or off, recovery might fail due to trying to fetch the commit timestamp for a transaction that did not record it.
“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
Randomize the random() seed in bootstrap and standalone backends, and in initdb (Noah Misch)
The main practical effect of this change is that it avoids a scenario where initdb might mistakenly conclude that POSIX shared memory is not available, due to name collisions caused by always using the same random seed.
“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 DSM allocation to be interrupted (Chris Travers)
“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 failure in a parallel worker when loading an extension that tries to access system caches within its init function (Thomas Munro)
We don't consider that to be good extension coding practice, but it mostly worked before parallel query, so continue to support it for now.
“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
Properly handle turning full_page_writes on dynamically (Kyotaro Horiguchi)
“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 possible crash due to double free() during SP-GiST rescan (Andrew Gierth)
“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 possible buffer overrun when replaying GIN page recompression from WAL (Alexander Korotkov, Sivasubramanian Ramasubramanian)
“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 missed fsync of a replication slot's directory (Konstantin Knizhnik, 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 unexpected timeouts when using wal_sender_timeout on a slow server (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
Ensure that hot standby processes use the correct WAL consistency point (Alexander Kukushkin, Michael Paquier)
This prevents possible misbehavior just after a standby server has reached a consistent database state during WAL replay.
“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 background workers are stopped properly when the postmaster receives a fast-shutdown request before completing database startup (Alexander Kukushkin)
“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 the free space map during WAL replay of page all-visible/frozen flag changes (Álvaro Herrera)
Previously we were not careful about this, reasoning that the FSM is not critical data anyway. However, if it's sufficiently out of date, that can result in significant performance degradation after a standby has been promoted to primary. The FSM will eventually be healed by updates, but we'd like it to be good sooner, so work harder at maintaining it during WAL replay.
“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 premature release of parallel-query resources when query end or tuple count limit is reached (Amit Kapila)
It's only okay to shut down the executor at this point if the caller cannot demand backwards scan afterwards.
“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
Don't run atexit callbacks when servicing SIGQUIT (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
Don't record foreign-server user mappings as members of extensions (Tom Lane)
If CREATE USER MAPPING is executed in an extension script, an extension dependency was created for the user mapping, which is unexpected. Roles can't be extension members, so user mappings shouldn't be either.
“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 syslogger more robust against failures in opening CSV log files (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 psql, as well as documentation examples, to call PQconsumeInput() before each PQnotifies() call (Tom Lane)
This fixes cases in which psql would not report receipt of a NOTIFY message until after the next command.
“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 possible inconsistency in pg_dump's sorting of dissimilar object names (Jacob Champion)
“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 pg_restore will schema-qualify the table name when emitting DISABLE/ENABLE TRIGGER commands (Tom Lane)
This avoids failures due to the new policy of running restores with restrictive search path.
“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_upgrade to handle event triggers in extensions correctly (Haribabu Kommi)
pg_upgrade failed to preserve an event trigger's extension-membership status.
“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_upgrade's cluster state check to work correctly on a standby server (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
Enforce type cube's dimension limit in all contrib/cube functions (Andrey Borodin)
Previously, some cube-related functions could construct values that would be rejected by cube_in(), leading to dump/reload failures.
“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/postgres_fdw, don't try to ship a variable-free ORDER BY clause to the remote server (Andrew Gierth)
“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 contrib/unaccent's unaccent() function to use the unaccent text search dictionary that is in the same schema as the function (Tom Lane)
Previously it tried to look up the dictionary using the search path, which could fail if the search path has a restrictive value.
“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 build problems on macOS 10.14 (Mojave) (Tom Lane)
Adjust configure to add an -isysroot switch to CPPFLAGS; without this, PL/Perl and PL/Tcl fail to configure or build on macOS 10.14. The specific sysroot used can be overridden at configure time or build time by setting the PG_SYSROOT variable in the arguments of configure or make.
It is now recommended that Perl-related extensions write $(perl_includespec) rather than -I$(perl_archlibexp)/CORE in their compiler flags. The latter continues to work on most platforms, but not recent macOS.
Also, it should no longer be necessary to specify --with-tclconfig manually to get PL/Tcl to build on recent macOS releases.
“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 MSVC build and regression-test scripts to work on recent Perl versions (Andrew Dunstan)
Perl no longer includes the current directory in its search path by default; work around that.
“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 Windows, allow the regression tests to be run by an Administrator account (Andrew Dunstan)
To do this safely, pg_regress now gives up any such privileges at startup.
“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 btree comparison functions to return INT_MIN (Tom Lane)
Up to now, we've forbidden datatype-specific comparison functions from returning INT_MIN, which allows callers to invert the sort order just by negating the comparison result. However, this was never safe for comparison functions that directly return the result of memcmp(), strcmp(), etc, as POSIX doesn't place any such restriction on those functions. At least some recent versions of memcmp() can return INT_MIN, causing incorrect sort ordering. Hence, we've removed this restriction. Callers must now use the INVERT_COMPARE_RESULT() macro if they wish to invert the sort order.
“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 recursion hazard in shared-invalidation message processing (Tom Lane)
This error could, for example, result in failure to access a system catalog or index that had just been processed by VACUUM FULL.
This change adds a new result code for LockAcquire, which might possibly affect external callers of that function, though only very unusual usage patterns would have an issue with it. The API of LockAcquireExtended is also changed.
“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
Save and restore SPI's global variables during SPI_connect() and SPI_finish() (Chapman Flack, Tom Lane)
This prevents possible interference when one SPI-using function calls another.
“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 using potentially-under-aligned page buffers (Tom Lane)
Invent new union types PGAlignedBlock and PGAlignedXLogBlock, and use these in place of plain char arrays, ensuring that the compiler can't place the buffer at a misaligned start address. This fixes potential core dumps on alignment-picky platforms, and may improve performance even on platforms that allow misalignment.
“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 src/port/snprintf.c follow the C99 standard's definition of snprintf()'s result value (Tom Lane)
On platforms where this code is used (mostly Windows), its pre-C99 behavior could lead to failure to detect buffer overrun, if the calling code assumed C99 semantics.
“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
When building on i386 with the clang compiler, require -msse2 to be used (Andres Freund)
This avoids problems with missed floating point overflow checks.
“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 configure's detection of the result type of strerror_r() (Tom Lane)
The previous coding got the wrong answer when building with icc on Linux (and perhaps in other cases), leading to libpq not returning useful error messages for system-reported errors.
“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 2018g for DST law changes in Chile, Fiji, Morocco, and Russia (Volgograd), plus historical corrections for China, Hawaii, Japan, Macau, and North Korea.
“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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