Received: from maia.hub.org (maia-3.hub.org [200.46.204.243]) by mail.postgresql.org (Postfix) with ESMTP id 05C631337B66 for ; Mon, 15 Nov 2010 11:13:08 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.243]) (amavisd-maia, port 10024) with ESMTP id 82997-01 for ; Mon, 15 Nov 2010 15:13:00 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id 6CFD01335B36 for ; Mon, 15 Nov 2010 11:13:00 -0400 (AST) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id oAFFCxj3013815; Mon, 15 Nov 2010 10:12:59 -0500 (EST) To: =?iso-8859-2?Q?Artur_Zaj=B1c?= cc: pgsql-performance@postgresql.org Subject: Re: Difference between explain analyze and real execution time In-reply-to: <000001cb849e$1dce2720$596a7560$@ang.com.pl> References: <000001cb849e$1dce2720$596a7560$@ang.com.pl> Comments: In-reply-to =?iso-8859-2?Q?Artur_Zaj=B1c?= message dated "Mon, 15 Nov 2010 09:21:34 +0100" Date: Mon, 15 Nov 2010 10:12:59 -0500 Message-ID: <13814.1289833979@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.91 tagged_above=-10 required=5 tests=BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201011/244 X-Sequence-Number: 41268 =?iso-8859-2?Q?Artur_Zaj=B1c?= writes: > Why there is so big difference between explain analyze (0.710 ms) and real > execution time (3309 ms)? EXPLAIN ANALYZE doesn't account for all of the runtime involved. In this case, I'd bet that session startup/shutdown is a big part of the difference. regards, tom lane