From: Alexander Korotkov <akorotkov@postgresql.org>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Add wait-for-lsn process-exit cleanup callback
Date: Tue, 18 Aug 2026 12:02:13 +0000
Message-ID: <E1wwIWC-000000013YL-20tG@gemulon.postgresql.org> (raw)
Add wait-for-lsn process-exit cleanup callback
WaitLSNCleanup() was called from ProcKill(), but not from
AuxiliaryProcKill(), even though xlogwait.c sizes its shared memory to
include NUM_AUXILIARY_PROCS and thus accepts calls from auxiliary
processes. Such a process exiting while waiting would leave its entry in
the heap.
Register an on_shmem_exit callback lazily before a process enters a
wait-for-lsn heap instead, as suggested by Noah: that keeps the cleanup
local to xlogwait.c and makes it harder to miss a caller that needs it,
rather than having to remember every process-kill path.
Reported-by: Noah Misch <noah@leadboat.com>
Author: Xuneng Zhou <xunengzhou@gmail.com>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
Discussion: https://postgr.es/m/20260706012642.f9.noahmisch%40microsoft.com
Discussion: https://postgr.es/m/CABPTF7UtW_cAa%3DQh4RDfKiUqu3pJJE22ai9tbWJVERbeRyssLw%40mail.gmail.com
Backpatch-through: 19
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/f994d2b71ebca8258f7c68be310077588aa62059
Modified Files
--------------
src/backend/access/transam/xlogwait.c | 38 +++++++++++++++++++++++++++++++++++
src/backend/storage/lmgr/proc.c | 6 ------
2 files changed, 38 insertions(+), 6 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: akorotkov@postgresql.org, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Add wait-for-lsn process-exit cleanup callback
In-Reply-To: <E1wwIWC-000000013YL-20tG@gemulon.postgresql.org>
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