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help / color / mirror / Atom feedFrom: Melanie Plageman <melanieplageman@gmail.com>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Avoid replay cleanup locks for freeze-only and VM-only records
Date: Tue, 22 Sep 2026 22:26:45 +0000
Message-ID: <E1x98wn-00000000pSy-2ngL@gemulon.postgresql.org> (raw)
Avoid replay cleanup locks for freeze-only and VM-only records
6dbb490261a combined pruning and freezing in a single WAL record but
unconditionally requested a cleanup lock during replay. Prior to version
17, freeze-only records were replayed under an ordinary exclusive lock.
1252a4ee286 subsequently folded visibility map updates into the same
records, extending the unnecessary cleanup-lock requirement to VM-only
updates starting in version 19.
Request a cleanup lock in redo only when the record actually prunes.
Freezing and visibility updates do not move or remove tuple storage, so
they need not wait for other buffer pins to be released. This avoids
unnecessary replay delays and cancellation of standby queries holding
buffer pins.
The fix is the same for all versions, though it addresses two oversights
in master/19 and one in 18/17.
Reported-by: Satyanarayana Narlapuram <satyanarlapuram@gmail.com>
Reported-by: Andrey Borodin <x4mmm@yandex-team.ru>
Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Discussion: https://postgr.es/m/85b6968b-49f2-4243-86a6-9b4116e6439b@iki.fi
Discussion: https://postgr.es/m/CAHg+QDf3NcB3vOAqQ5EFcV5DYYUZ9snCSJAU-x1JDbtcjK3eBQ@mail.gmail.com
Discussion: https://postgr.es/m/F9BF304E-1298-481C-829A-B4E10AED025A@yandex-team.ru
Backpatch-through: 17
Branch
------
REL_19_STABLE
Details
-------
https://git.postgresql.org/pg/commitdiff/1139b7effdd3573406c52f1e9c5c3b59cdfbc43e
Modified Files
--------------
src/backend/access/heap/pruneheap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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To: pgsql-committers@postgresql.org
Cc: melanieplageman@gmail.com, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Avoid replay cleanup locks for freeze-only and VM-only records
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