Received: from maia.hub.org (maia-2.hub.org [200.46.204.251]) by mail.postgresql.org (Postfix) with ESMTP id E6AEDB5DDAE for ; Mon, 5 Sep 2011 11:39:36 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.251]) (amavisd-maia, port 10024) with ESMTP id 22767-10 for ; Mon, 5 Sep 2011 14:39:30 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from elizabeth.gransy.com (elizabeth.gransy.com [89.187.132.199]) by mail.postgresql.org (Postfix) with ESMTP id 9E131B5DDB3 for ; Mon, 5 Sep 2011 11:39:30 -0300 (ADT) Received: from sq.gransy.com (localhost [127.0.0.1]) by elizabeth.gransy.com (Postfix) with ESMTP id 7A0F815E432D; Mon, 5 Sep 2011 16:39:30 +0200 (CEST) Received: from 85.162.13.254 (SquirrelMail authenticated user tv@fuzzy.cz) by sq.gransy.com with HTTP; Mon, 5 Sep 2011 16:39:30 +0200 Message-ID: In-Reply-To: <4E64D7EA.3010704@ai.wu.ac.at> References: <4E61D6B4.9090804@ai.wu.ac.at> <33fadeb6ac1bade5ef01bd08d1fd7807.squirrel@sq.gransy.com> <4E64D3D3.8000205@squeakycode.net> <4E64D7EA.3010704@ai.wu.ac.at> Date: Mon, 5 Sep 2011 16:39:30 +0200 Subject: Re: Sudden drop in DBb performance From: "Tomas Vondra" To: "Gerhard Wohlgenannt" Cc: "Andy Colson" , "Tomas Vondra" , pgsql-performance@postgresql.org, "Heinz-Peter Lang" , "Gerhard Wohlgenannt" , "Weichselbraun, Albert" User-Agent: SquirrelMail/1.4.21 MIME-Version: 1.0 Content-Type: text/plain;charset=utf-8 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-0.001 tagged_above=-10 required=5 tests=BAYES_40=-0.001 X-Spam-Level: X-Archive-Number: 201109/38 X-Sequence-Number: 44814 On 5 Září 2011, 16:08, Gerhard Wohlgenannt wrote: > Below please find the results of vmstat 2 over some periode of time .. > with normal database / system load. What does a "normal load" mean? Does that mean a time when the queries are slow? Are you sure the machine really has 48GB of RAM? Because from the vmstat output it seems like there's just 32GB. procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 1342168 336936 107636 31353512 0 0 14 183 1911 3426 2 1 93 4 1342168 + 336936 + 107636 + 31353512 = 33140252 ~ 31GB BTW there's 1.3GB of swap, although it's not used heavily (according to the vmstat output). Otherwise I don't see anything wrong in the output. What is the size of the database (use pg_database_size to get it)? Did it grow significantly recently? Tomas