Received: from localhost (maia-2.hub.org [200.46.204.187]) by postgresql.org (Postfix) with ESMTP id 495D29FB425 for ; Tue, 30 Jan 2007 14:07:52 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.187]) (amavisd-new, port 10024) with ESMTP id 17832-09 for ; Tue, 30 Jan 2007 14:07:37 -0400 (AST) 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 904B19FB404 for ; Tue, 30 Jan 2007 14:07:43 -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 l0UI7E3E020999; Tue, 30 Jan 2007 10:07:20 -0800 Received: by perhan.alvh.no-ip.org (Postfix, from userid 1000) id D87637C83; Tue, 30 Jan 2007 14:04:43 -0300 (CLST) Date: Tue, 30 Jan 2007 14:04:43 -0300 From: Alvaro Herrera To: Gregory Stark Cc: Luke Lonergan , Chad Wagner , Simon Riggs , Igor Lobanov , Richard Huxton , pgsql-performance@postgresql.org Subject: Re: Querying distinct values from a large table Message-ID: <20070130170443.GJ2303@alvh.no-ip.org> Mail-Followup-To: Gregory Stark , Luke Lonergan , Chad Wagner , Simon Riggs , Igor Lobanov , Richard Huxton , pgsql-performance@postgresql.org References: <87d54wmpvd.fsf@stark.xeocode.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87d54wmpvd.fsf@stark.xeocode.com> 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]); Tue, 30 Jan 2007 10:07:33 -0800 (PST) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200701/432 X-Sequence-Number: 23033 Gregory Stark wrote: > (Incidentally I'm not sure where 2-5x comes from. It's entirely dependant on > your data distribution. It's not hard to come up with distributions where it's > 1000x as fast and others where there's no speed difference.) So the figure is really "1-1000x"? I bet this one is more impressive in PHB terms. -- Alvaro Herrera http://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support