b36fbd9f8d
The replication slot stats stored in shared memory rely on an internal index number. Both pgstat_reset_replslot() and pgstat_fetch_replslot() lacked some LWLock protections with ReplicationSlotControlLock while operating on these index numbers. This issue could cause these two functions to potentially operate on incorrect slots when taken in isolation in the event of slots dropped and/or re-created concurrently. Note that pg_stat_get_replication_slot() is called once per slot when querying pg_stat_replication_slots, meaning that the stats are retrieved across multiple ReplicationSlotControlLock acquisitions. So, while this commit improves more consistency, it may still be possible that statistics are not completely consistent for a single scan of pg_stat_replication_slots under concurrent replication slot drop or creation activity. The issue should unlikely be a problem in practice, causing the report of inconsistent stats or or the stats reset of an incorrect slot, so no backpatch is done. Author: Bertrand Drouvot Reviewed-by: Heikki Linnakangas, Shveta Malik, Michael Paquier Discussion: https://postgr.es/m/ZeGq1HDWFfLkjh4o@ip-10-97-1-34.eu-west-3.compute.internal
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/.