0cecc908e9
Commit 5b562644fec696977df4a82790064e8287927891 added a comment that SetRelationHasSubclass() callers must hold this lock. When commit 17f206fbc824d2b4b14480199ca9ff7dea417eda extended use of this column to partitioned indexes, it didn't take the lock. As the latter commit message mentioned, we currently never reset a partitioned index to relhassubclass=f. That largely avoids harm from the lock omission. The cause for fixing this now is to unblock introducing a rule about locks required to heap_update() a pg_class row. This might cause more deadlocks. It gives minor user-visible benefits: - If an ALTER INDEX SET TABLESPACE runs concurrently with ALTER TABLE ATTACH PARTITION or CREATE PARTITION OF, one transaction blocks instead of failing with "tuple concurrently updated". (Many cases of DDL concurrency still fail that way.) - Match ALTER INDEX ATTACH PARTITION in choosing to lock the index. While not user-visible today, we'll need this if we ever make something set the flag to false for a partitioned index, like ANALYZE does today for tables. Back-patch to v12 (all supported versions), the plan for the commit relying on the new rule. In back branches, add LockOrStrongerHeldByMe() instead of adding a LockHeldByMe() parameter. Reviewed (in an earlier version) by Robert Haas. Discussion: https://postgr.es/m/20240611024525.9f.nmisch@google.com
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.