Re: PATCH to allow concurrent VACUUMs to not lock each
Alvaro Herrera <alvherre@commandprompt.com>
From: Alvaro Herrera <alvherre@commandprompt.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Hannu Krosing <hannu@skype.net>, Bruce Momjian <bruce@momjian.us>, Neil Conway <neilc@samurai.com>, pgsql-patches@postgresql.org
Date: 2006-07-30T19:21:39Z
Lists: pgsql-hackers
Tom Lane wrote: > Hannu Krosing <hannu@skype.net> writes: > > Ãhel kenal päeval, P, 2006-07-30 kell 14:11, kirjutas Alvaro Herrera: > >> What was idea behind moving vac_update_relstats to a separate > >> transaction? I'm wondering if it's still needed, if it further enhances > >> the system somehow, or your patch did something differently than what > >> was applied. > > > The part of transactions which actually modified the data (iirc it updates > > relpages and reltuples in pg_class) is not safe to ignore by concurrent > > vacuum, say a vacuum on pg_class . > > But that's done as a nontransactional update, or at least was the last > time I looked, so there's no need to do it in a separate xact. > > Knew I should have taken time to review that patch before it went in ... Which one? The one I applied doesn't have this change. (You are still more than welcome to review it of course.) -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support