Received: from localhost (unknown [200.46.204.183]) by developer.postgresql.org (Postfix) with ESMTP id 101B82E0079 for ; Mon, 2 Jun 2008 22:20:19 -0300 (ADT) Received: from developer.postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 89991-05 for ; Mon, 2 Jun 2008 22:20:09 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from oxford.xeocode.com (87-127-95-198.no-dns-yet.enta.net [87.127.95.198]) by developer.postgresql.org (Postfix) with ESMTP id E3FFF2E0072 for ; Mon, 2 Jun 2008 22:20:14 -0300 (ADT) Received: from localhost ([127.0.0.1] helo=oxford.xeocode.com) by oxford.xeocode.com with esmtp (Exim 4.69) (envelope-from ) id 1K3LC6-0002MB-NK; Tue, 03 Jun 2008 02:20:10 +0100 To: "Scott Marlowe" Cc: "Justin" , Subject: Re: getting estimated cost to agree with actual In-Reply-To: (Scott Marlowe's message of "Mon\, 2 Jun 2008 17\:38\:21 -0600") User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.1 (gnu/linux) X-Draft-From: ("nnimap+mail01.enterprisedb.com:INBOX.performance" 5840) References: <4844696D.20307@emproshunts.com> From: Gregory Stark Organization: EnterpriseDB Date: Tue, 03 Jun 2008 02:20:10 +0100 Message-ID: <87mym3iab9.fsf@oxford.xeocode.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200806/6 X-Sequence-Number: 30356 "Scott Marlowe" writes: > On Mon, Jun 2, 2008 at 3:43 PM, Justin wrote: >> >> I have noticed that estimated Cost to do the query is way off from Actual. > > Well, they're not measured in the same units. estimated costs are in > terms of the cost to sequentially scan a single tuple, while actual > costs are in milliseconds. s/tuple/page/ -- Gregory Stark EnterpriseDB http://www.enterprisedb.com Ask me about EnterpriseDB's On-Demand Production Tuning