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 6DBD19DCAA3 for ; Thu, 15 Dec 2005 19:44:52 -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 05883-03 for ; Thu, 15 Dec 2005 19:44:54 -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 B833E9DCA02 for ; Thu, 15 Dec 2005 19:44:49 -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 jBFNinRI088867 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 15 Dec 2005 16:44:51 -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 jBFNinx0047459; Thu, 15 Dec 2005 16:44:49 -0700 (MST) (envelope-from mfuhr@winnie.fuhr.org) Received: (from mfuhr@localhost) by winnie.fuhr.org (8.13.4/8.13.4/Submit) id jBFNimhO047458; Thu, 15 Dec 2005 16:44:48 -0700 (MST) (envelope-from mfuhr) Date: Thu, 15 Dec 2005 16:44:48 -0700 From: Michael Fuhr To: Tom Lane Cc: Merlin Moncure , pgsql-performance@postgresql.org, Carlos Benkendorf Subject: Re: How much expensive are row level statistics? Message-ID: <20051215234448.GA47382@winnie.fuhr.org> References: <6EE64EF3AB31D5448D0007DD34EEB3417DDAC9@Herge.rcsinc.local> <2506.1134428461@sss.pgh.pa.us> <20051213010751.GA63416@winnie.fuhr.org> <1667.1134444045@sss.pgh.pa.us> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1667.1134444045@sss.pgh.pa.us> X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.014 required=5 tests=[AWL=0.014] X-Spam-Score: 0.014 X-Spam-Level: X-Archive-Number: 200512/360 X-Sequence-Number: 16181 On Mon, Dec 12, 2005 at 10:20:45PM -0500, Tom Lane wrote: > Given the rather lackadaisical way in which the stats collector makes > the data available, it seems like the backends are being much too > enthusiastic about posting their stats_command_string status > immediately. Might be worth thinking about how to cut back the > overhead by suppressing some of these messages. Would a GUC setting akin to log_min_duration_statement be feasible? Does the backend support, or could it be easily modified to support, a mechanism that would post the command string after a configurable amount of time had expired, and then continue processing the query? That way admins could avoid the overhead of posting messages for short-lived queries that nobody's likely to see in pg_stat_activity anyway. -- Michael Fuhr