Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id 868469FA66C for ; Fri, 29 Sep 2006 09:25:42 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 33652-01 for ; Fri, 29 Sep 2006 09:25:38 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from mail.logix-tt.com (mail.logix-tt.com [212.211.145.186]) by postgresql.org (Postfix) with ESMTP id 3C0D59FA5FB for ; Fri, 29 Sep 2006 09:25:38 -0300 (ADT) Received: from kingfisher.intern.logix-tt.com (84-72-188-217.dclient.hispeed.ch [84.72.188.217]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.logix-tt.com (Postfix) with ESMTP id 1F2D8656BE; Fri, 29 Sep 2006 14:27:59 +0200 (CEST) Received: from [127.0.0.1] (localhost [127.0.0.1]) by kingfisher.intern.logix-tt.com (Postfix) with ESMTP id F01B218815B01; Fri, 29 Sep 2006 14:25:33 +0200 (CEST) Message-ID: <451D10BD.6060206@logix-tt.com> Date: Fri, 29 Sep 2006 14:25:33 +0200 From: Markus Schaber Reply-To: PostgreSQL Performance List Organization: Logical Tracking and Tracing International AG, Switzerland User-Agent: Thunderbird 1.5.0.5 (X11/20060812) MIME-Version: 1.0 To: pgsql-performance@postgresql.org Cc: Carlo Stonebanks Subject: Re: Performace Optimization for Dummies References: <5EE4B6D1-8ECE-4033-A912-DFD9146A5A93@blighty.com> <6B702C4D-C102-44E3-841C-BF176EAF1CAB@blighty.com> <20060928235243.GH34238@nasby.net> In-Reply-To: X-Enigmail-Version: 0.94.0.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0.185 tagged_above=0 required=5 tests=AWL, FORGED_RCVD_HELO X-Spam-Level: X-Archive-Number: 200609/426 X-Sequence-Number: 21112 Hi, Carlo, Carlo Stonebanks wrote: > From what I can see, autovacuum is hitting the db's in question about once > every five minutes. Does this imply an ANALYZE is being done automatically > that would meet the requirements we are talking about here? Is there any > benefit ot explicitly performing an ANALYZE? Autovacuum looks at the modification statistics (they count how much modifications happened on the table), and decides whether it's time to VACUUM (reclaim empty space) and ANALYZE (update column value distributions) the table. The exact thresholds for Autovacuum to kick in are configurable, see the docs. HTH, Markus -- Markus Schaber | Logical Tracking&Tracing International AG Dipl. Inf. | Software Development GIS Fight against software patents in Europe! www.ffii.org www.nosoftwarepatents.org