Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1VPf69-0005It-8p for pgsql-performance@arkaria.postgresql.org; Fri, 27 Sep 2013 20:57:13 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1VPf68-0000rG-7e for pgsql-performance@arkaria.postgresql.org; Fri, 27 Sep 2013 20:57:12 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1VPf67-0000rA-Ah for pgsql-performance@postgresql.org; Fri, 27 Sep 2013 20:57:11 +0000 Received: from smtp.01.com ([199.36.142.181]) by magus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1VPf63-0001Wh-8c for pgsql-performance@postgresql.org; Fri, 27 Sep 2013 20:57:10 +0000 Received: from localhost (localhost [127.0.0.1]) by smtp-out-1.01.com (Postfix) with ESMTP id 40ECF29402C; Fri, 27 Sep 2013 15:57:05 -0500 (CDT) X-Virus-Scanned: amavisd-new at smtp-out-1.01.com Received: from smtp.01.com ([127.0.0.1]) by localhost (smtp-out-1.01.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id tqabUQx2Kyx4; Fri, 27 Sep 2013 15:57:05 -0500 (CDT) Received: from smtp.01.com (localhost [127.0.0.1]) by smtp-out-1.01.com (Postfix) with ESMTP id 1FF952940C9; Fri, 27 Sep 2013 15:57:05 -0500 (CDT) Received: from localhost (localhost [127.0.0.1]) by smtp-out-1.01.com (Postfix) with ESMTP id 0AF81294084; Fri, 27 Sep 2013 15:57:05 -0500 (CDT) X-Virus-Scanned: amavisd-new at smtp-out-1.01.com Received: from smtp.01.com ([127.0.0.1]) by localhost (smtp-out-1.01.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id qIiFo7cDExbS; Fri, 27 Sep 2013 15:57:04 -0500 (CDT) Received: from [172.47.23.102] (50-1-86-157.dsl.dynamic.sonic.net [50.1.86.157]) by smtp-out-1.01.com (Postfix) with ESMTPSA id 152E42940E2; Fri, 27 Sep 2013 15:57:03 -0500 (CDT) Message-ID: <5245F11E.20804@agliodbs.com> Date: Fri, 27 Sep 2013 13:57:02 -0700 From: Josh Berkus Organization: PostgreSQL Experts Inc. User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130803 Thunderbird/17.0.8 MIME-Version: 1.0 To: Andres Freund CC: Jeff Janes , "pgsql-performance@postgresql.org" Subject: Re: Planner performance extremely affected by an hanging transaction (20-30 times)? References: <1379944816.30390.YahooMailNeo@web162903.mail.bf1.yahoo.com> <5815.1380018947@sss.pgh.pa.us> <5241CF2A.2070309@agliodbs.com> <20130925175312.GB5578@awork2.anarazel.de> <20130925184330.GC5578@awork2.anarazel.de> In-Reply-To: X-Enigmail-Version: 1.5.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: -1.9 (-) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-performance Precedence: bulk Sender: pgsql-performance-owner@postgresql.org Andres, Jeff, >> As far as I can tell, the only downside of doing that is that, since hint >> bits might be set later, it is possible some dirty pages will get written >> unhinted and then re-dirtied by the hint bit setting, when more aggressive >> setting would have only one combined dirty write instead. But that seems >> rather hypothetical, and if it really is a problem we should probably >> tackle it directly rather than by barring other optimizations. > > I am - as evidenced - too tired to think about this properly, but I > think you might be right here. Any thoughts on a fix for this we could get into 9.2.5? -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance