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 63AC19DC85A for ; Mon, 13 Mar 2006 20:19:12 -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 98245-01 for ; Mon, 13 Mar 2006 20:19:14 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from tigger.fuhr.org (tigger.fuhr.org [63.214.45.158]) by postgresql.org (Postfix) with ESMTP id 660FA9DC856 for ; Mon, 13 Mar 2006 20:19:08 -0400 (AST) Received: from winnie.fuhr.org (winnie.fuhr.org [10.1.0.1]) by tigger.fuhr.org (8.13.3/8.13.3) with ESMTP id k2E0Is3x095291 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 13 Mar 2006 17:18:58 -0700 (MST) (envelope-from mfuhr@winnie.fuhr.org) Received: from winnie.fuhr.org (localhost [127.0.0.1]) by winnie.fuhr.org (8.13.4/8.13.4) with ESMTP id k2E0Isd7090879; Mon, 13 Mar 2006 17:18:54 -0700 (MST) (envelope-from mfuhr@winnie.fuhr.org) Received: (from mfuhr@localhost) by winnie.fuhr.org (8.13.4/8.13.4/Submit) id k2E0IrAv090878; Mon, 13 Mar 2006 17:18:53 -0700 (MST) (envelope-from mfuhr) Date: Mon, 13 Mar 2006 17:18:53 -0700 From: Michael Fuhr To: "mcelroy, tim" Cc: "'pgsql-performance@postgresql.org'" Subject: Re: PG Statistics Message-ID: <20060314001853.GA90740@winnie.fuhr.org> References: <0C4841B42F87D51195BD00B0D020F5CB044B2466@morpheus.bostonstock.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0C4841B42F87D51195BD00B0D020F5CB044B2466@morpheus.bostonstock.com> X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.121 required=5 tests=[AWL=0.121] X-Spam-Score: 0.121 X-Spam-Level: X-Archive-Number: 200603/172 X-Sequence-Number: 17609 On Mon, Mar 13, 2006 at 06:49:39PM -0500, mcelroy, tim wrote: > Does anyone know how much of a performance hit turning stats_block_level and > stats_row_level on will incur? Do both need to be on to gather cache > related statistics? I know the annotated_conf_80 document states to only > turn them on for debug but if they're not that performance intensive I > cannot see the harm. I ran some tests a few months ago and found that stats_command_string had a significant impact, whereas stats_block_level and stats_row_level were almost negligible. Here are my test results: http://archives.postgresql.org/pgsql-performance/2005-12/msg00307.php Your results may vary. If you see substantially different results then please post the particulars. -- Michael Fuhr