Received: from magus.postgresql.org ([87.238.57.229]) by malur.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1T15dJ-0002Sa-GW for pgsql-performance@postgresql.org; Tue, 14 Aug 2012 01:09:21 +0000 Received: from smtp.01.com ([199.36.142.181]) by magus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1T15dF-0004iv-Gz for pgsql-performance@postgresql.org; Tue, 14 Aug 2012 01:09:21 +0000 Received: from localhost (localhost.localdomain [127.0.0.1]) by smtp-out-2.01.com (Postfix) with ESMTP id 8DF324F66EB for ; Mon, 13 Aug 2012 20:09:16 -0500 (CDT) X-Virus-Scanned: amavisd-new at smtp-out-2.01.com Received: from smtp.01.com ([127.0.0.1]) by localhost (smtp-out-2.01.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id IcM+ZW64-fTr for ; Mon, 13 Aug 2012 20:09:16 -0500 (CDT) Received: from smtp.01.com (localhost.localdomain [127.0.0.1]) by smtp-out-2.01.com (Postfix) with ESMTP id 64E3C3900CE for ; Mon, 13 Aug 2012 20:09:16 -0500 (CDT) Received: from Sidney-Stratton.local (70-36-143-92.dsl.dynamic.sonic.net [70.36.143.92]) by smtp-out-2.01.com (Postfix) with ESMTPSA id 161E34F66EB for ; Mon, 13 Aug 2012 20:09:15 -0500 (CDT) Message-ID: <5029A543.4090503@agliodbs.com> Date: Mon, 13 Aug 2012 18:09:23 -0700 From: Josh Berkus Organization: PostgreSQL Experts Inc. User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:14.0) Gecko/20120713 Thunderbird/14.0 MIME-Version: 1.0 To: pgsql-performance@postgresql.org Subject: Re: Increasing WAL usage followed by sudden drop References: <385621813.89890122.1344620116156.JavaMail.root@email> In-Reply-To: <385621813.89890122.1344620116156.JavaMail.root@email> X-Enigmail-Version: 1.4.3 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: -1.9 (-) X-Archive-Number: 201208/75 X-Sequence-Number: 47613 > Any ideas on any of this? Why the sawteeth? Why the rise-then-drop? Well, my first thought on the sawteeth is that you have archive_timeout set to 15 minutes. No? As for the gradual buildup over days, that most likely corresponds to either changes in application activity levels, or some kind of weekly data purge cycle which shrinks your database every weekend. Since I don't know anything about your admin or your application, that's a best guess. -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com