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 5F67211F6785 for ; Thu, 30 Mar 2006 11:16:19 -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 98682-08 for ; Thu, 30 Mar 2006 11:16:18 -0400 (AST) X-Greylist: domain auto-whitelisted by SQLgrey- Received: from mail.gmx.net (mail.gmx.net [213.165.64.20]) by postgresql.org (Postfix) with SMTP id 33BAF11F66EE for ; Thu, 30 Mar 2006 11:16:15 -0400 (AST) Received: (qmail invoked by alias); 30 Mar 2006 15:16:15 -0000 Received: from dslb-084-063-051-003.pools.arcor-ip.net (EHLO colt.pezone.net) [84.63.51.3] by mail.gmx.net (mp042) with SMTP; 30 Mar 2006 17:16:15 +0200 X-Authenticated: #495269 From: Peter Eisentraut To: Tom Lane Subject: Re: Index scan startup time Date: Thu, 30 Mar 2006 17:16:13 +0200 User-Agent: KMail/1.8.3 Cc: Michael Stone , pgsql-performance@postgresql.org References: <200603301359.11038.peter_e@gmx.net> <20060330132915.GL6811@mathom.us> <14358.1143728757@sss.pgh.pa.us> In-Reply-To: <14358.1143728757@sss.pgh.pa.us> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200603301716.13840.peter_e@gmx.net> X-Y-GMX-Trusted: 0 X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.133 required=5 tests=[AWL=0.133] X-Spam-Score: 0.133 X-Spam-Level: X-Archive-Number: 200603/622 X-Sequence-Number: 18059 Tom Lane wrote: > The problem here appears to be a non-random correlation between state > and activity, such that the desired state values are not randomly > scattered in the activity sequence. The planner doesn't know about > that correlation and hence can't predict the poor startup time. So from when to when is the startup time (the "x" in "x..y") actually measured? When does the clock start ticking and when does it stop? That is what's confusing me. -- Peter Eisentraut http://developer.postgresql.org/~petere/