Received: from localhost (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 6CC5064FD95 for ; Sat, 13 Dec 2008 10:30:35 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 05901-09 for ; Sat, 13 Dec 2008 10:30:33 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from smtp192.iad.emailsrvr.com (smtp192.iad.emailsrvr.com [207.97.245.192]) by mail.postgresql.org (Postfix) with ESMTP id 2C85E64FD87 for ; Sat, 13 Dec 2008 10:30:32 -0400 (AST) Received: from relay9.relay.iad.mlsrvr.com (localhost [127.0.0.1]) by relay9.relay.iad.mlsrvr.com (SMTP Server) with ESMTP id 4C8C71DFCCA; Sat, 13 Dec 2008 09:30:31 -0500 (EST) Received: by relay9.relay.iad.mlsrvr.com (Authenticated sender: matthew-AT-zeut.net) with ESMTPA id 3783B1DF21C; Sat, 13 Dec 2008 09:30:31 -0500 (EST) Message-ID: <4943C70C.9070307@zeut.net> Date: Sat, 13 Dec 2008 09:30:36 -0500 From: "Matthew T. O'Connor" User-Agent: Thunderbird 2.0.0.18 (Windows/20081105) MIME-Version: 1.0 To: Michael Monnerie CC: "pgsql-admin@postgresql.org" Subject: Re: What is VACUUM waiting for? References: <200812122355.25481@zmi.at> In-Reply-To: <200812122355.25481@zmi.at> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200812/109 X-Sequence-Number: 30942 Michael Monnerie wrote: > Dear list, this is postgres 8.1, and I run a dbmail mailserver where we deleted most e-mails. > I then did a VACUUM (see below), and just before the "dbmail_messages" truncated rows > there was a very long time where obviously nothing happened. No CPU usage (<8%) and > no disk I/O (usage <5%). You can see this from the details: > DETAIL: CPU 0.11s/0.23u sec elapsed 294.24 sec. > I would have expected I/Os at least. How does VACUUM work at all? > Do you have any vacuum delay setting turned on? Perhaps they are too high?