Horton

Re: vacuumdb changes for stats import/export

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Frédéric Yhuel <frederic.yhuel@dalibo.com>
Cc: Corey Huinker <corey.huinker@gmail.com>, Bruce Momjian <bruce@momjian.us>, "David G. Johnston" <david.g.johnston@gmail.com>, John Naylor <johncnaylorls@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Jeff Davis <pgsql@j-davis.com>, jian he <jian.universality@gmail.com>, Matthias van de Meent <boekewurm+postgres@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Magnus Hagander <magnus@hagander.net>, Stephen Frost <sfrost@snowman.net>, Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>, Peter Smith <smithpb2250@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, alvherre@alvh.no-ip.org
Date: 2025-07-28T14:47:22Z
Lists: pgsql-hackers 
On Sun, Jul 27, 2025 at 12:46:44PM +0200, Frédéric Yhuel wrote:
> Then it seems very unlikely that the query optimizer's choices become
> transiently worse because of that, doesn't it? and this shouldn't be used to
> justify this option, IMHO.

I can't remember who wrote this line, but it was borrowed from the
--analyze-in-stages description.  The point is that if you use
--analyze-in-stages without --missing-stats-only, there will be a period
where existing statistics will be replaced with ones generated with lower
statistics targets.  Obviously, this wording isn't clear enough.  We might
need to either remove that sentence or add "When used in conjunction with
--analyze-in-stages..."

-- 
nathan

Commits

  1. doc: Adjust documentation for vacuumdb --missing-stats-only.

  2. Update guidance for running vacuumdb after pg_upgrade.

  3. vacuumdb: Add option for analyzing only relations missing stats.

  4. vacuumdb: Teach vacuum_one_database() to reuse query results.