Trigger more frequent autovacuums with relallfrozen
authorMelanie Plageman <melanieplageman@gmail.com>
Mon, 3 Mar 2025 19:42:00 +0000 (14:42 -0500)
committerMelanie Plageman <melanieplageman@gmail.com>
Mon, 3 Mar 2025 19:42:00 +0000 (14:42 -0500)
commit06eae9e6218ab2acf64ea497bad0360e4c90e32d
treec9346e7a784ad9dcd4947c65bf6abadc24ada853
parent35c8dd9e1176ae0c3cb060b0da9cb2bba925363c
Trigger more frequent autovacuums with relallfrozen

Calculate the insert threshold for triggering an autovacuum of a
relation based on the number of unfrozen pages.

By only considering the unfrozen portion of the table when calculating
how many tuples to add to the insert threshold, we can trigger more
frequent vacuums of insert-heavy tables. This increases the chances of
vacuuming those pages when they still reside in shared buffers

This also increases the number of autovacuums triggered by tuples
inserted and not by wraparound risk. We prefer to freeze these pages
during insert-triggered autovacuums, as anti-wraparound vacuums are not
automatically canceled by conflicting lock requests.

We calculate the unfrozen percentage of the table using the recently
added (99f8f3fbbc8f) relallfrozen column of pg_class.

Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Reviewed-by: Greg Sabino Mullane <htamfids@gmail.com>
Reviewed-by: Robert Treat <rob@xzilla.net>
Reviewed-by: wenhui qiu <qiuwenhuifx@gmail.com>
Discussion: https://postgr.es/m/flat/CAAKRu_aj-P7YyBz_cPNwztz6ohP%2BvWis%3Diz3YcomkB3NpYA--w%40mail.gmail.com
doc/src/sgml/catalogs.sgml
doc/src/sgml/config.sgml
src/backend/postmaster/autovacuum.c
src/backend/utils/misc/postgresql.conf.sample