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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
2017-02-09
9.6.2 HistoricalSupport ends 2021-11-11
A dump/restore is not required for those running 9.6.X.
However, if your installation has been affected by the bug described in the first changelog entry below, then after updating you may need to take action to repair corrupted indexes.
Also, if you are upgrading from a version earlier than 9.6.1, see Section E.24.
Changes
Fix a race condition that could cause indexes built with CREATE INDEX CONCURRENTLY to be corrupt (Pavan Deolasee, Tom Lane)
If CREATE INDEX CONCURRENTLY was used to build an index that depends on a column not previously indexed, then rows updated by transactions that ran concurrently with the CREATE INDEX command could have received incorrect index entries. If you suspect this may have happened, the most reliable solution is to rebuild affected indexes after installing this update.
“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 special snapshot used for catalog scans is not invalidated by premature data pruning (Tom Lane)
Backends failed to account for this snapshot when advertising their oldest xmin, potentially allowing concurrent vacuuming operations to remove data that was still needed. This led to transient failures along the lines of "cache lookup failed for relation 1255".
“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 incorrect WAL logging for BRIN indexes (Kuntal Ghosh)
The WAL record emitted for a BRIN "revmap" page when moving an index tuple to a different page was incorrect. Replay would make the related portion of the index useless, forcing it to be recomputed.
“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
Unconditionally WAL-log creation of the "init fork" for an unlogged table (Michael Paquier)
Previously, this was skipped when wal_level = minimal, but actually it's necessary even in that case to ensure that the unlogged table is properly reset to empty 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
If the stats collector dies during hot standby, restart it (Takayuki Tsunakawa)
“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 feedback works correctly when it's enabled at standby server start (Ants Aasma, Craig Ringer)
“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
Check for interrupts while hot standby is waiting for a conflicting query (Simon Riggs)
“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 constantly respawning the autovacuum launcher in a corner case (Amit Khandekar)
This fix avoids problems when autovacuum is nominally off and there are some tables that require freezing, but all such tables are already being processed by autovacuum workers.
“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 setting the num_sync field to zero in synchronous_standby_names (Fujii Masao)
The correct way to disable synchronous standby is to set the whole value to an empty string.
Changes
Don't count background worker processes against a user's connection limit (David Rowley)
Changes
Fix check for when an extension member object can be dropped (Tom Lane)
Extension upgrade scripts should be able to drop member objects, but this was disallowed for serial-column sequences, and possibly other 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 tracking of initial privileges for extension member objects so that it works correctly with ALTER EXTENSION ... ADD/DROP (Stephen Frost)
An object's current privileges at the time it is added to the extension will now be considered its default privileges; only later changes in its privileges will be dumped by subsequent pg_dump runs.
Changes
Make sure ALTER TABLE preserves index tablespace assignments when rebuilding indexes (Tom Lane, Michael Paquier)
Previously, non-default settings of default_tablespace could result in broken indexes.
“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 incorrect updating of trigger function properties when changing a foreign-key constraint's deferrability properties with ALTER TABLE ... ALTER CONSTRAINT (Tom Lane)
This led to odd failures during subsequent exercise of the foreign key, as the triggers were fired at the wrong times.
“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 dropping a foreign-key constraint if there are pending trigger events for the referenced relation (Tom Lane)
This avoids "could not find trigger NNN" or "relation NNN has no triggers" 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
Fix ALTER TABLE ... SET DATA TYPE ... USING when child table has different column ordering than the parent (Álvaro Herrera)
Failure to adjust the column numbering in the USING expression led to errors, typically "attribute N has wrong 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
Fix processing of OID column when a table with OIDs is associated to a parent with OIDs via ALTER TABLE ... INHERIT (Amit Langote)
The OID column should be treated the same as regular user columns in this case, but it wasn't, leading to odd behavior in later inheritance changes.
“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 CREATE TABLE ... LIKE ... WITH OIDS creates a table with OIDs, whether or not the LIKE-referenced table(s) have OIDs (Tom Lane)
Changes
Fix CREATE OR REPLACE VIEW to update the view query before attempting to apply the new view options (Dean Rasheed)
Previously the command would fail if the new options were inconsistent with the old view definition.
“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
Report correct object identity during ALTER TEXT SEARCH CONFIGURATION (Artur Zakirov)
The wrong catalog OID was reported to extensions such as 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 commit timestamp mechanism to not fail when queried about the special XIDs FrozenTransactionId and BootstrapTransactionId (Craig Ringer)
“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 incorrect use of view reloptions as regular table reloptions (Tom Lane)
The symptom was spurious "ON CONFLICT is not supported on table ... used as a catalog table" errors when the target of INSERT ... ON CONFLICT is a view with cascade option.
“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 incorrect "target lists can have at most N entries" complaint when using ON CONFLICT with wide tables (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 spurious "query provides a value for a dropped column" errors during INSERT or UPDATE on a table with a dropped column (Tom Lane)
Changes
Prevent multicolumn expansion of foo.* in an UPDATE source expression (Tom Lane)
This led to "UPDATE target count mismatch --- internal error". Now the syntax is understood as a whole-row variable, as it would be in other contexts.
“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 column typmods are determined accurately for multi-row VALUES constructs (Tom Lane)
This fixes problems occurring when the first value in a column has a determinable typmod (e.g., length for a varchar value) but later values don't share the same limit.
“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
Throw error for an unfinished Unicode surrogate pair at the end of a Unicode string (Tom Lane)
Normally, a Unicode surrogate leading character must be followed by a Unicode surrogate trailing character, but the check for this was missed if the leading character was the last character in a Unicode string literal (U&'...') or Unicode identifier (U&"...").
“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 execution of DISTINCT and ordered aggregates when multiple such aggregates are able to share the same transition state (Heikki Linnakangas)
Changes
Fix implementation of phrase search operators in tsquery (Tom Lane)
Remove incorrect, and inconsistently-applied, rewrite rules that tried to transform away AND/OR/NOT operators appearing below a PHRASE operator; instead upgrade the execution engine to handle such cases correctly. This fixes assorted strange behavior and possible crashes for text search queries containing such combinations. Also fix nested PHRASE operators to work sanely in combinations other than simple left-deep trees, correct the behavior when removing stopwords from a phrase search clause, and make sure that index searches behave consistently with simple sequential-scan application of such queries.
Changes
Ensure that a purely negative text search query, such as !foo, matches empty tsvectors (Tom Dunstan)
Such matches were found by GIN index searches, but not by sequential scans or GiST index searches.
“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 when ts_rewrite() replaces a non-top-level subtree with an empty query (Artur Zakirov)
“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 performance problems in ts_rewrite() (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 ts_rewrite()'s handling of nested NOT operators (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
Improve speed of user-defined aggregates that use array_append() as transition function (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 array_fill() to handle empty arrays properly (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 possible crash in array_position() or array_positions() when processing arrays of records (Junseok Yang)
“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 one-byte buffer overrun in quote_literal_cstr() (Heikki Linnakangas)
The overrun occurred only if the input consisted entirely of single quotes and/or backslashes.
“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 multiple calls of pg_start_backup() and pg_stop_backup() from running concurrently (Michael Paquier)
This avoids an assertion failure, and possibly worse things, if someone tries to run these functions in parallel.
“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 transform that attempted to remove no-op AT TIME ZONE conversions (Tom Lane)
This resulted in wrong answers when the simplified expression was used in an index condition.
“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 discarding interval-to-interval casts that aren't really no-ops (Tom Lane)
In some cases, a cast that should result in zeroing out low-order interval fields was mistakenly deemed to be a no-op and discarded. An example is that casting from INTERVAL MONTH to INTERVAL YEAR failed to clear the months field.
“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 crash if the number of workers available to a parallel query decreases during a rescan (Andreas Seltenreich)
Changes
Fix bugs in transmitting GUC parameter values to parallel workers (Michael Paquier, 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
Allow statements prepared with PREPARE to be given parallel plans (Amit Kapila, Tobias Bussmann)
Changes
Fix incorrect generation of parallel plans for semi-joins (Tom Lane)
Changes
Fix planner's cardinality estimates for parallel joins (Robert Haas)
Ensure that these estimates reflect the number of rows predicted to be seen by each worker, rather than the total.
Changes
Fix planner to avoid trying to parallelize plan nodes containing initplans or subplans (Tom Lane, Amit Kapila)
Changes
Ensure that cached plans are invalidated by changes in foreign-table options (Amit Langote, Etsuro Fujita, Ashutosh Bapat)
“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 the plan generated for sorted partial aggregation with a constant GROUP BY clause (Tom Lane)
Changes
Fix "could not find plan for CTE" planner error when dealing with a UNION ALL containing CTE references (Tom Lane)
Changes
Fix mishandling of initplans when forcibly adding a Material node to a subplan (Tom Lane)
The typical consequence of this mistake was a "plan should not reference subplan's variable" error.
Changes
Fix foreign-key-based join selectivity estimation for semi-joins and anti-joins, as well as inheritance cases (Tom Lane)
The new code for taking the existence of a foreign key relationship into account did the wrong thing in these cases, making the estimates worse not better than the pre-9.6 code.
Changes
Fix pg_dump to emit the data of a sequence that is marked as an extension configuration table (Michael Paquier)
Changes
Fix mishandling of ALTER DEFAULT PRIVILEGES ... REVOKE in pg_dump (Stephen Frost)
pg_dump missed issuing the required REVOKE commands in cases where ALTER DEFAULT PRIVILEGES had been used to reduce privileges to less than they would normally be.
Changes
Fix pg_dump to dump user-defined casts and transforms that use built-in functions (Stephen Frost)
“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_restore with --create --if-exists to behave more sanely if an archive contains unrecognized DROP commands (Tom Lane)
This doesn't fix any live bug, but it may improve the behavior in future if pg_restore is used with an archive generated by a later pg_dump version.
“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_basebackup's rate limiting in the presence of slow I/O (Antonin Houska)
If disk I/O was transiently much slower than the specified rate limit, the calculation overflowed, effectively disabling the rate limit for the rest of the run.
“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_basebackup's handling of symlinked pg_stat_tmp and pg_replslot subdirectories (Magnus Hagander, 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 possible pg_basebackup failure on standby server when including WAL files (Amit Kapila, Robert Haas)
“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 initdb to insert the correct platform-specific default values for the xxx_flush_after parameters into postgresql.conf (Fabien Coelho, Tom Lane)
This is a cleaner way of documenting the default values than was used previously.
Changes
Fix possible mishandling of expanded arrays in domain check constraints and CASE execution (Tom Lane)
It was possible for a PL/pgSQL function invoked in these contexts to modify or even delete an array value that needs to be preserved for additional operations.
“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 nested uses of PL/pgSQL functions in contexts such as domain check constraints evaluated during assignment to a PL/pgSQL variable (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
Ensure that the Python exception objects we create for PL/Python are properly reference-counted (Rafa de la Torre, Tom Lane)
This avoids failures if the objects are used after a Python garbage collection cycle has occurred.
“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/Tcl to support triggers on tables that have .tupno as a column name (Tom Lane)
This matches the (previously undocumented) behavior of PL/Tcl's spi_exec and spi_execp commands, namely that a magic .tupno column is inserted only if there isn't a real column named 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
Allow DOS-style line endings in ~/.pgpass files, even on Unix (Vik Fearing)
This change simplifies use of the same password file across Unix and Windows machines.
“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 one-byte buffer overrun if ecpg is given a file name that ends with a dot (Takayuki Tsunakawa)
“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 incorrect error reporting for duplicate data in psql's \crosstabview (Tom Lane)
psql sometimes quoted the wrong row and/or column values when complaining about multiple entries for the same crosstab cell.
Changes
Fix psql's tab completion for ALTER DEFAULT PRIVILEGES (Gilles Darold, Stephen Frost)
“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 tab completion for ALTER TABLE t ALTER c DROP ... (Kyotaro Horiguchi)
Changes
In psql, treat an empty or all-blank setting of the PAGER environment variable as meaning "no pager" (Tom Lane)
Previously, such a setting caused output intended for the pager to vanish entirely.
“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 contrib/dblink's reporting of low-level libpq errors, such as out-of-memory (Joe 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
Teach contrib/dblink to ignore irrelevant server options when it uses a contrib/postgres_fdw foreign server as the source of connection options (Corey Huinker)
Previously, if the foreign server object had options that were not also libpq connection options, an error occurred.
“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 portability problems in contrib/pageinspect's functions for GIN indexes (Peter Eisentraut, 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 possible miss of socket read events while waiting on Windows (Amit Kapila)
This error was harmless for most uses, but it is known to cause hangs when trying to use the pldebugger extension.
Changes
On Windows, ensure that environment variable changes are propagated to DLLs built with debug options (Christian Ullrich)
“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
Sync our copy of the timezone library with IANA release tzcode2016j (Tom Lane)
This fixes various issues, most notably that timezone data installation failed if the target directory didn't support hard links.
“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 2016j for DST law changes in northern Cyprus (adding a new zone Asia/Famagusta), Russia (adding a new zone Europe/Saratov), Tonga, and Antarctica/Casey. Historical corrections for Italy, Kazakhstan, Malta, and Palestine. Switch to preferring numeric zone abbreviations for Tonga.
“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.
Entries come from the original English manuals. Release coverage and commit evidence are verified against upstream sources. Every entry retains its complete explanation and source link. Categories aid browsing; read the full notes for impact, conditions, and migration steps.
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.
CVE results are calculated independently from the PostgreSQL security registry and vulnerability records. A CVE counts as gained protection only when the source is affected and the target is fixed or unaffected. Remaining vulnerabilities are listed separately. Security entries and distinct CVEs are counted separately.
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