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Re: New GUC autovacuum_max_threshold ?

Sami Imseih <samimseih@gmail.com>

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From: Sami Imseih <samimseih@gmail.com>
To: Nathan Bossart <nathandbossart@gmail.com>
Cc: Frédéric Yhuel <frederic.yhuel@dalibo.com>, Robert Treat <rob@xzilla.net>, wenhui qiu <qiuwenhuifx@gmail.com>, Robert Haas <robertmhaas@gmail.com>, "Imseih (AWS), Sami" <simseih@amazon.com>, David Rowley <dgrowleyml@gmail.com>, Joe Conway <mail@joeconway.com>, Michael Banck <mbanck@gmx.net>, Laurenz Albe <laurenz.albe@cybertec.at>, Melanie Plageman <melanieplageman@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-01-14T19:46:00Z
Lists: pgsql-hackers 
Will just park the idea for the documentation here. If
you feel this should be in a follow-up patch, I am ok
with that and will follow-up on it afterwards.

+++ b/doc/src/sgml/maintenance.sgml
@@ -905,6 +905,12 @@ vacuum threshold = Minimum(vacuum max threshold,
vacuum base threshold + vacuum
     <xref linkend="guc-autovacuum-vacuum-scale-factor"/>,
     and the number of tuples is
     <structname>pg_class</structname>.<structfield>reltuples</structfield>.
+    With the default values of <xref
linkend="autovacuum_vacuum_scale_factor"/> and
+    <xref linkend="autovacuum_vacuum_threshold"/>, the <quote>vacuum
threshold</quote> increases as
+    the number of tuples in the table increases; and this reduces the
table's eligibility for
+    <command>VACUUM</command>. Therefore,
+    <xref linkend="autovacuum_vacuum_max_threshold"/> provides a cap
on the number of obsolete rows
+    before the table becomes eligible for a vacuum.
    </para>

Regards,

Sami

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Introduce autovacuum_vacuum_max_threshold.

  2. Consolidate docs for vacuum-related GUCs in new subsection