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
2016-10-27
9.1.24 HistoricalSupport ends 2016-10-27
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 EvalPlanQual rechecks involving CTE scans (Tom Lane)
The recheck would always see the CTE as returning no rows, typically leading to failure to update rows that were recently updated.
“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 improper repetition of previous results from hashed aggregation in a subquery (Andrew Gierth)
The test to see if we can reuse a previously-computed hash table of the aggregate state values neglected the possibility of an outer query reference appearing in an aggregate argument expression. A change in the value of such a reference should lead to recalculating the hash table, but did not.
“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 timeout length when VACUUM is waiting for exclusive table lock so that it can truncate the table (Simon Riggs)
The timeout was meant to be 50 milliseconds, but it was actually only 50 microseconds, causing VACUUM to give up on truncation much more easily than intended. Set it to the intended 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
Remove artificial restrictions on the values accepted by numeric_in() and numeric_recv() (Tom Lane)
We allow numeric values up to the limit of the storage format (more than 1e100000), so it seems fairly pointless that numeric_in() rejected scientific-notation exponents above 1000. Likewise, it was silly for numeric_recv() to reject more than 1000 digits in an input 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
Avoid very-low-probability data corruption due to testing tuple visibility without holding buffer lock (Thomas Munro, Peter Geoghegan, 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 file descriptor leakage when truncating a temporary relation of more than 1GB (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
Disallow starting a standalone backend with standby_mode turned on (Michael Paquier)
This can't do anything useful, since there will be no WAL receiver process to fetch more WAL data; and it could result in misbehavior in code that wasn't designed with this situation in mind.
“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 try to share SSL contexts across multiple connections in libpq (Heikki Linnakangas)
This led to assorted corner-case bugs, particularly when trying to use different SSL parameters for different connections.
“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 corner-case memory leak in libpq (Tom Lane)
The reported problem involved leaking an error report during PQreset(), but there might be related 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
Make ecpg's --help and --version options work consistently with our other executables (Haribabu Kommi)
“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/intarray/bench/bench.pl to print the results of the EXPLAIN it does when given the -e option (Daniel Gustafsson)
“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 failure of obsolete dynamic time zone abbreviations (Tom Lane)
If a dynamic time zone abbreviation does not match any entry in the referenced time zone, treat it as equivalent to the time zone name. This avoids unexpected failures when IANA removes abbreviations from their time zone database, as they did in tzdata release 2016f and seem likely to do again in the future. The consequences were not limited to not recognizing the individual abbreviation; any mismatch caused the pg_timezone_abbrevs view to fail altogether.
“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 2016h for DST law changes in Palestine and Turkey, plus historical corrections for Turkey and some regions of Russia. Switch to numeric abbreviations for some time zones in Antarctica, the former Soviet Union, and Sri Lanka.
The IANA time zone database previously provided textual abbreviations for all time zones, sometimes making up abbreviations that have little or no currency among the local population. They are in process of reversing that policy in favor of using numeric UTC offsets in zones where there is no evidence of real-world use of an English abbreviation. At least for the time being, PostgreSQL will continue to accept such removed abbreviations for timestamp input. But they will not be shown in the pg_timezone_names view nor used for output.
In this update, AMT is no longer shown as being in use to mean Armenia Time. Therefore, we have changed the Default abbreviation set to interpret it as Amazon Time, thus UTC-4 not UTC+4.
“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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