PostgreSQL 13.21 release changes

Avoid one-byte buffer overread when examining invalidly-encoded strings that are claimed to be in GB18030 encoding (Noah Misch, Andres Freund) § §

While unlikely, a SIGSEGV crash could occur if an incomplete multibyte character appeared at the end of memory. This was possible both in the server and in libpq-using applications. (CVE-2025-4207)

Handle self-referential foreign keys on partitioned tables correctly (Álvaro Herrera) §

Creating or attaching partitions failed to make the required catalog entries for a foreign-key constraint, if the table referenced by the constraint was the same partitioned table. This resulted in failure to enforce the constraint fully.

To fix this, you should drop and recreate any self-referential foreign keys on partitioned tables, if partitions have been created or attached since the constraint was created. Bear in mind that violating rows might already be present, in which case recreating the constraint will fail, and you'll need to fix up those rows before trying again.

Fix unexpected “attribute has wrong type” errors in UPDATE, DELETE, and MERGE queries that use whole-row table references to views or functions in FROM (Tom Lane) § § §

Correctly process references to outer CTE names that appear within a WITH clause attached to an INSERT/UPDATE/DELETE/MERGE command that's inside WITH (Tom Lane) §

The parser failed to detect disallowed recursion cases, nor did it account for such references when sorting CTEs into a usable order.

Fix ARRAY(subquery) and ARRAY[expression, ...] constructs to produce sane results when the input is of type int2vector or oidvector (Tom Lane) §

This patch restores the behavior that existed before PostgreSQL 9.5: the result is of type int2vector[] or oidvector[].

Fix possible erroneous reports of invalid affixes while parsing Ispell dictionaries (Jacob Brazeal) §

Fix ALTER TABLE ADD COLUMN to correctly handle the case of a domain type that has a default (Jian He, Tom Lane, Tender Wang) § §

If a domain type has a default, adding a column of that type (without any explicit DEFAULT clause) failed to install the domain's default value in existing rows, instead leaving the new column null.

Improve the error message for disallowed attempts to alter the properties of a foreign key constraint (Álvaro Herrera) §

Avoid error when resetting the relhassubclass flag of a temporary table that's marked ON COMMIT DELETE ROWS (Noah Misch) §

Disable “skip fetch” optimization in bitmap heap scan (Matthias van de Meent) §

It turns out that this optimization can result in returning dead tuples when a concurrent vacuum marks a page all-visible.

Fix performance issues in GIN index search startup when there are many search keys (Tom Lane, Vinod Sridharan) § §

An indexable clause with many keys (for example, jsonbcol ?| array[...] with tens of thousands of array elements) took O(N²) time to start up, and was uncancelable for that interval too.

Detect missing support procedures in a BRIN index operator class, and report an error instead of crashing (Álvaro Herrera) §

Fix race condition in handling of synchronous_standby_names immediately after startup (Melnikov Maksim, Michael Paquier) §

For a short period after system startup, backends might fail to wait for synchronous commit even though synchronous_standby_names is enabled.

Fix pg_strtof() to not crash with null endptr (Alexander Lakhin, Tom Lane) §

Avoid crash when a Snowball stemmer encounters an out-of-memory condition (Maksim Korotkov) §

Skip WAL recycling and preallocation during archive recovery, to avoid corruption of WAL files that were restored from the archive (Noah Misch, Arun Thirupathi) § § § § § § §

This change back-patches v15-era fixes that were considered largely cosmetic at the time, but turn out to prevent data corruption in the wake of subsequent fixes.

Prevent over-advancement of catalog xmin in “fast forward” mode of logical decoding (Zhijie Hou) §

This mistake could allow deleted catalog entries to be vacuumed away even though they were still potentially needed by the WAL-reading process.

Avoid data loss when DDL operations that don't take a strong lock affect tables that are being logically replicated (Shlok Kyal, Hayato Kuroda) § §

The catalog changes caused by the DDL command were not reflected into WAL-decoding processes, allowing them to decode subsequent changes using stale catalog data, probably resulting in data corruption.

Avoid duplicate snapshot creation in logical replication index lookups (Heikki Linnakangas) § §

Fix overly-strict assertion in gistFindCorrectParent() (Heikki Linnakangas) §

In PL/pgSQL, avoid “unexpected plan node type” error when a scrollable cursor is defined on a simple SELECT expression query (Andrei Lepikhov) §

Don't try to drop individual index partitions in pg_dump's --clean mode (Jian He) §

The server rejects such DROP commands. That has no real consequences, since the partitions will go away anyway in the subsequent DROPs of either their parent tables or their partitioned index. However, the error reported for the attempted drop causes problems when restoring in --single-transaction mode.

In pg_dumpall, avoid emitting invalid role GRANT commands if pg_auth_members contains invalid role OIDs (Tom Lane) §

Instead, print a warning and skip the entry. This copes better with catalog corruption that has been seen to occur in back branches as a result of race conditions between GRANT and DROP ROLE.

Allow contrib/dblink queries to be interrupted by query cancel (Noah Misch) § §

This change back-patches a v17-era fix. It prevents possible hangs in CREATE DATABASE and DROP DATABASE due to failure to detect deadlocks.

Avoid crashing with corrupt input data in contrib/pageinspect's heap_page_items() (Dmitry Kovalenko) §

Prevent assertion failure in contrib/pg_freespacemap's pg_freespacemap() (Tender Wang) §

Applying pg_freespacemap() to a relation lacking storage (such as a view) caused an assertion failure, although there was no ill effect in non-assert builds. Add an error check to reject that case.

Fix build failure on macOS 15.4 (Tom Lane, Peter Eisentraut) §

This macOS update broke our configuration probe for strchrnul().

Update time zone data files to tzdata release 2025b for DST law changes in Chile, plus historical corrections for Iran (Tom Lane) §

There is a new time zone America/Coyhaique for Chile's Aysén Region, to account for it changing to UTC-03 year-round and thus diverging from America/Santiago.