From: Alvaro Herrera <alvherre@commandprompt.com>
To: Stefano Nichele <stefano.nichele@gmail.com>
Cc: pgsql-admin@postgresql.org
Subject: Re: strange autovacuum behaviour
Date: Tue, 10 Feb 2009 11:07:42 -0300
Message-ID: <20090210140742.GG3708@alvh.no-ip.org> (raw)
In-Reply-To: <49906B4F.5040509@gmail.com>
References: <49906B4F.5040509@gmail.com>
Stefano Nichele escribió:
> Hi All,
> I have a couple of questions about autovacuum/vacuum behavior.
>
> On my production system, I set autovacuum ON since it's pretty hard to
> me find a good timeframe for vacuum (the system is pretty busy over the day)
> Last week the system was really slow and running vacuum manually the
> performance was really improved.
> So now I would like to understand why autovacuum did not work as
> expected (at least for me). Any ideas ?
Maybe the autovacuum naptime was set too high. Or perhaps the threshold
and scale settings were too high. Maybe the vacuum_cost_delay for
autovacuum was too high.
> Why autovacuum (that was OFF) started ? For preventing transaction ID
> wraparound ? Is it right that in such case all the tables are
> (auto)vacuumed ?
Not necessarily all tables; only those that require a vacuum to prevent
xid wraparound. (It was all tables in 8.1, but this changed in 8.2).
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-admin@postgresql.org
Cc: alvherre@commandprompt.com, stefano.nichele@gmail.com
Subject: Re: strange autovacuum behaviour
In-Reply-To: <20090210140742.GG3708@alvh.no-ip.org>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox