From: Peter Geoghegan <pg@bowt.ie>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Use simplehash for backend-private buffer pin refcounts.
Date: Thu, 12 Mar 2026 17:26:44 +0000
Message-ID: <E1w0jo4-003dzm-1m@gemulon.postgresql.org> (raw)
Use simplehash for backend-private buffer pin refcounts.
Replace dynahash with simplehash for the per-backend PrivateRefCountHash
overflow table. Simplehash generates inlined, open-addressed lookup
code, avoiding the per-call overhead of dynahash that becomes noticeable
when many buffers are pinned with a CPU-bound workload.
Motivated by testing of the index prefetching patch, which pins many
more buffers concurrently than typical index scans.
Author: Peter Geoghegan <pg@bowt.ie>
Suggested-by: Andres Freund <andres@anarazel.de>
Reviewed-By: Tomas Vondra <tomas@vondra.me>
Reviewed-By: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CAH2-Wz=g=JTSyDB4UtB5su2ZcvsS7VbP+ZMvvaG6ABoCb+s8Lw@mail.gmail.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/a367c433ad015b889ee296b07de00017819915c4
Modified Files
--------------
src/backend/storage/buffer/bufmgr.c | 68 +++++++++++++++++++------------------
src/tools/pgindent/typedefs.list | 2 ++
2 files changed, 37 insertions(+), 33 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: pg@bowt.ie, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Use simplehash for backend-private buffer pin refcounts.
In-Reply-To: <E1w0jo4-003dzm-1m@gemulon.postgresql.org>
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