From: Melanie Plageman <melanieplageman@gmail.com>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Simplify vacuum VM update logging counters
Date: Thu, 26 Jun 2025 18:26:30 +0000
Message-ID: <E1uUrIs-003T4S-1x@gemulon.postgresql.org> (raw)
Simplify vacuum VM update logging counters
We can simplify the VM counters added in dc6acfd910b8 to
lazy_vacuum_heap_page() and lazy_scan_new_or_empty().
We won't invoke lazy_vacuum_heap_page() unless there are dead line
pointers, so we know the page can't be all-visible.
In lazy_scan_new_or_empty(), we only update the VM if the page-level
hint PD_ALL_VISIBLE is clear, and the VM bit cannot be set if the page
level bit is clear because a subsequent page update would fail to clear
the visibility map bit.
Simplify the logic for determining which log counters to increment based
on this knowledge. Doing so is worthwhile because the old logic was
confusing and misguided.
Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Nazir Bilal Yavuz <byavuz81@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/flat/CAAKRu_a9w_n2mwY%3DG4LjfWTvRTJtjbfvnYAKi4WjO8QXHHrA0g%40mail.gmail.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/060f420a03a8d8186423e7d64302b72e01365c20
Modified Files
--------------
src/backend/access/heap/vacuumlazy.c | 53 +++++++++++-------------------------
1 file changed, 16 insertions(+), 37 deletions(-)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-committers@postgresql.org
Cc: melanieplageman@gmail.com, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Simplify vacuum VM update logging counters
In-Reply-To: <E1uUrIs-003T4S-1x@gemulon.postgresql.org>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox