Horton

Re: Trigger more frequent autovacuums of heavy insert tables

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: wenhui qiu <qiuwenhuifx@gmail.com>
Cc: Melanie Plageman <melanieplageman@gmail.com>, Robert Treat <rob@xzilla.net>, Greg Sabino Mullane <htamfids@gmail.com>, Robert Haas <robertmhaas@gmail.com>, Pg Hackers <pgsql-hackers@postgresql.org>, Andres Freund <andres@anarazel.de>, Peter Geoghegan <pg@bowt.ie>, David Rowley <dgrowley@gmail.com>, Corey Huinker <corey.huinker@gmail.com>
Date: 2025-03-01T17:50:56Z
Lists: pgsql-hackers 
On Sat, Mar 01, 2025 at 08:57:52AM +0800, wenhui qiu wrote:
> Based on the comments, the  pcnt_unfrozen   value could potentially be 0,
> which would indicate that everything is frozen. Therefore,  is it necessary
> to handle the case where the value is 0.？

How so?  If it's 0, then the insert threshold calculation would produce
autovacuum_vacuum_insert_threshold, just like for an empty table.  That
seems like the intended behavior to me.

-- 
nathan

Commits

  1. doc: Update formula for vacuum insert threshold.

  2. Redefine pg_class.reltuples to be -1 before the first VACUUM or ANALYZE.

  3. Measure the number of all-visible pages for use in index-only scan costing.