Commits on Aug 22, 2026

1. Prevent deadlock between ALTER TABLE recursion and ATTACH PARTITION

   ALTER TABLE commands that recurse to partitions (e.g. ALTER COLUMN SET
   DEFAULT) lock partitions in ascending OID order using find_all_inheritors().
   In contrast, ALTER TABLE ATTACH PARTITION may lock ancestor tables in
   reverse OID order while recursively collecting partition constraints.
   When these two operations run concurrently, this lock order inversion
   can lead to a deadlock.
   To avoid this, pre-lock all ancestor partitioned tables in OID order
   when processing ALTER TABLE ATTACH PARTITION. This ensures a consistent
   lock ordering before any recursive traversal of the partition hierarchy
   occurs.
   The ancestor locks are taken early, via RangeVarCallbackForAlterRelation(),
   so that they precede the standard ALTER TABLE locking of the target
   relation.
   This fixes a reproducible deadlock observed on the current master
   branch with deep partition hierarchies.
   Author: Chao Li <lic@highgo.com>
   Reviewed-by:
   Discussion: https://postgr.es/m/

   

   authored and Commitfest Bot committed

   Aug 22, 2026
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