From 06eae9e6218ab2acf64ea497bad0360e4c90e32d Mon Sep 17 00:00:00 2001 From: Melanie Plageman Date: Mon, 3 Mar 2025 14:42:00 -0500 Subject: 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 Reviewed-by: Nathan Bossart Reviewed-by: Greg Sabino Mullane Reviewed-by: Robert Treat Reviewed-by: wenhui qiu Discussion: https://postgr.es/m/flat/CAAKRu_aj-P7YyBz_cPNwztz6ohP%2BvWis%3Diz3YcomkB3NpYA--w%40mail.gmail.com --- doc/src/sgml/catalogs.sgml | 7 ++++--- doc/src/sgml/config.sgml | 15 +++++++-------- 2 files changed, 11 insertions(+), 11 deletions(-) (limited to 'doc/src') diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 9a21a0d6f15..fb050635551 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -2072,9 +2072,10 @@ SCRAM-SHA-256$<iteration count>:&l Number of pages that are marked all-frozen in the table's visibility - map. This is only an estimate and can be used along with - relallvisible for scheduling vacuums and - tuning vacuum's freezing + map. This is only an estimate used for triggering autovacuums. It can + also be used along with relallvisible for + scheduling manual vacuums and tuning vacuum's freezing behavior. It is updated by diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index e55700f35b8..d2fa5f7d1a9 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -8773,14 +8773,13 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv; - Specifies a fraction of the table size to add to - autovacuum_vacuum_insert_threshold - when deciding whether to trigger a VACUUM. - The default is 0.2 (20% of table size). - This parameter can only be set in the postgresql.conf - file or on the server command line; - but the setting can be overridden for individual tables by - changing table storage parameters. + Specifies a fraction of the unfrozen pages in the table to add to + autovacuum_vacuum_insert_threshold when deciding + whether to trigger a VACUUM. The default is + 0.2 (20% of unfrozen pages in table). This + parameter can only be set in the postgresql.conf + file or on the server command line; but the setting can be overridden + for individual tables by changing table storage parameters. -- cgit v1.2.3