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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Melanie Plageman <melanieplageman@gmail.com>
Cc: Fujii Masao <masao.fujii@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Andrey Borodin <x4mmm@yandex-team.ru>
Cc: Andres Freund <andres@anarazel.de>
Cc: Matthias van de Meent <boekewurm+postgres@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>
Subject: Re: Why clearing the VM doesn't require registering vm buffer in wal record
Date: Sun, 19 Jul 2026 22:34:29 -0400
Message-ID: <1065814.1784514869@sss.pgh.pa.us> (raw)
In-Reply-To: <CAAKRu_Y9DZ7=AXpUfX+ESgavoHFbS8if_2gmp-B6tP6vJxzXWA@mail.gmail.com>
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	<CAAKRu_YmzD3JODw4ZHfvK+R+_12A5sDX8eM=n=4ej1phm+902g@mail.gmail.com>
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Melanie Plageman <melanieplageman@gmail.com> writes:
> I've committed this.

Coverity complained about this patch:

/srv/coverity/git/pgsql-git/postgresql/src/backend/access/heap/pruneheap.c: 951             in heap_page_fix_vm_corruption()
945             MarkBufferDirtyHint(prstate->buffer, true);
946         }
947     
948         if (do_clear_vm)
949         {
950             LockBuffer(prstate->vmbuffer, BUFFER_LOCK_EXCLUSIVE);
>>>     CID 1697133:         Error handling issues  (CHECKED_RETURN)
>>>     Calling "visibilitymap_clear" without checking return value (as is done elsewhere 13 out of 14 times).
951             visibilitymap_clear(prstate->relation->rd_locator, prstate->block,
952                                 prstate->vmbuffer,
953                                 VISIBILITYMAP_VALID_BITS);
954             LockBuffer(prstate->vmbuffer, BUFFER_LOCK_UNLOCK);
955             prstate->old_vmbits = 0;
956         }

I think it's right to complain --- if we check for failure everywhere
else, why's it OK to not check here?  If it is OK, a comment and an
explicit cast to "(void)" would be appropriate.

			regards, tom lane






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  Cc: tgl@sss.pgh.pa.us, melanieplageman@gmail.com, masao.fujii@gmail.com, robertmhaas@gmail.com, x4mmm@yandex-team.ru, andres@anarazel.de, boekewurm+postgres@gmail.com, pgsql-hackers@lists.postgresql.org, hlinnaka@iki.fi
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