From: | Michael Paquier <michael(at)paquier(dot)xyz> |
---|---|
To: | pgsql-committers(at)lists(dot)postgresql(dot)org |
Subject: | pgsql: Prevent inconsistent use of stats entry for replication slots |
Date: | 2024-06-05 23:49:14 |
Message-ID: | E1sF0NV-000AIg-H4@gemulon.postgresql.org |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-committers |
Prevent inconsistent use of stats entry for replication slots
Concurrent activity around replication slot creation and drop could
cause a replication slot to use a stats entry it should not have used
when created, triggering an assertion failure when retrieving an
inconsistent entry from the dshash table used by the stats facility.
The issue is that pgstat_drop_replslot() calls pgstat_drop_entry()
without checking the result. If pgstat_drop_entry() cannot free the
entry related to the object dropped, pgstat_request_entry_refs_gc()
should be called. AtEOXact_PgStat_DroppedStats() and surrounding
routines dropping stats entries already do that.
This is documented in pgstat_internal.h, but let's add a comment at the
top of pgstat_drop_entry() as that can be easy to miss.
Reported-by: Alexander Lakhin
Author: Floris Van Nee
Analyzed-by: Andres Freund
Discussion: https://postgr.es/m/17947-b9554521ad963c9c@postgresql.org
Backpatch-through: 15
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/cd312adc561a0de056bbc0b0087d275bd3e9f282
Modified Files
--------------
src/backend/utils/activity/pgstat_replslot.c | 5 +++--
src/backend/utils/activity/pgstat_shmem.c | 11 +++++++++++
2 files changed, 14 insertions(+), 2 deletions(-)
From | Date | Subject | |
---|---|---|---|
Next Message | Bruce Momjian | 2024-06-06 00:53:17 | pgsql: doc PG 17 relnotes: adjust integer bin/oct funcs and psql tab |
Previous Message | Nathan Bossart | 2024-06-05 20:35:43 | pgsql: Fix documentation for POSIX semaphores. |