X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 0328F9DC95C for ; Tue, 17 Jan 2006 11:09:47 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 42525-10 for ; Tue, 17 Jan 2006 11:09:50 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from r1.mycybernet.net (r1.mycybernet.net [209.5.206.8]) by postgresql.org (Postfix) with ESMTP id 47EC09DC94A for ; Tue, 17 Jan 2006 11:09:44 -0400 (AST) Received: from 227-54-222-209.mycybernet.net ([209.222.54.227]:34754 helo=phlogiston.dydns.org) by r1.mycybernet.net with esmtp (Exim 4.50 (FreeBSD)) id 1EysSy-000BwO-Qv for pgsql-performance@postgresql.org; Tue, 17 Jan 2006 10:09:48 -0500 Received: by phlogiston.dydns.org (Postfix, from userid 1000) id 76EAF4069; Tue, 17 Jan 2006 10:09:48 -0500 (EST) Date: Tue, 17 Jan 2006 10:09:48 -0500 From: Andrew Sullivan To: pgsql-performance@postgresql.org Subject: Re: Autovacuum / full vacuum Message-ID: <20060117150948.GG21092@phlogiston.dyndns.org> References: <43CCC711.504@familyhealth.com.au> <43CCFA7E.1060307@zeut.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43CCFA7E.1060307@zeut.net> User-Agent: Mutt/1.5.9i X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.08 required=5 tests=[AWL=0.080] X-Spam-Score: 0.08 X-Spam-Level: X-Archive-Number: 200601/240 X-Sequence-Number: 16718 On Tue, Jan 17, 2006 at 09:09:02AM -0500, Matthew T. O'Connor wrote: > vacuum. As long as that percentage is small enough, the effect on > performance is negligible. Have you measured to see if things are truly Actually, as long as the percentage is small enough and the pages are really empty, the performance effect is positive. If you have VACUUM FULLed table, inserts have to extend the table before inserting, whereas in a table with some space reclaimed, the I/O effect of having to allocate another disk page is already done. A -- Andrew Sullivan | ajs@crankycanuck.ca When my information changes, I alter my conclusions. What do you do sir? --attr. John Maynard Keynes