Received: from localhost (maia-5.hub.org [200.46.204.182]) by postgresql.org (Postfix) with ESMTP id 72CCB9FB284; Thu, 11 Jan 2007 15:49:45 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.182]) (amavisd-new, port 10024) with ESMTP id 30504-05; Thu, 11 Jan 2007 15:49:35 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from lists.commandprompt.com (host-254.commandprompt.net [207.173.203.254]) by postgresql.org (Postfix) with ESMTP id AAFD29FB279; Thu, 11 Jan 2007 15:49:37 -0400 (AST) Received: from perhan.alvh.no-ip.org (200-126-100-202.bk7-dsl.surnet.cl [200.126.100.202]) (authenticated bits=0) by lists.commandprompt.com (8.13.7/8.13.6) with ESMTP id l0BJnWgQ003752; Thu, 11 Jan 2007 11:49:37 -0800 Received: by perhan.alvh.no-ip.org (Postfix, from userid 1000) id D8B4D32A02; Thu, 11 Jan 2007 16:49:28 -0300 (CLST) Date: Thu, 11 Jan 2007 16:49:28 -0300 From: Alvaro Herrera To: Tom Lane Cc: Kim , pgsql-performance@postgresql.org, pgsql-hackers@postgresql.org Subject: Re: [HACKERS] unusual performance for vac following 8.2 upgrade Message-ID: <20070111194928.GC10464@alvh.no-ip.org> Mail-Followup-To: Tom Lane , Kim , pgsql-performance@postgresql.org, pgsql-hackers@postgresql.org References: <45A671CD.1050706@myemma.com> <27939.1168539652@sss.pgh.pa.us> <45A68C74.4080405@myemma.com> <28949.1168544710@sss.pgh.pa.us> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <28949.1168544710@sss.pgh.pa.us> User-Agent: Mutt/1.5.13 (2006-08-11) X-Virus-Scanned: ClamAV version 0.88.5, clamav-milter version 0.88.5 on projects.commandprompt.com X-Virus-Status: Clean X-Greylist: Sender succeded SMTP AUTH authentication, not delayed by milter-greylist-1.6 (lists.commandprompt.com [192.168.2.159]); Thu, 11 Jan 2007 11:49:37 -0800 (PST) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200701/183 X-Sequence-Number: 22784 Tom Lane wrote: > What I think we need to do about this is > > (1) fix pgstat_vacuum_tabstats to have non-O(N^2) behavior; I'm thinking > of using a hash table for the OIDs instead of a linear list. Should be > a pretty small change; I'll work on it today. > > (2) Reconsider whether last-vacuum-time should be sent to the collector > unconditionally. (2) seems a perfectly reasonably answer, but ISTM (1) would be good to have anyway (at least in HEAD). -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc.