X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (unknown [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id A8FF552A51 for ; Tue, 19 Jul 2005 13:54:26 -0300 (ADT) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 73382-10 for ; Tue, 19 Jul 2005 16:54:23 +0000 (GMT) Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by svr1.postgresql.org (Postfix) with ESMTP id 6FB8E52A36 for ; Tue, 19 Jul 2005 13:54:22 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id j6JGsMkD007323; Tue, 19 Jul 2005 12:54:22 -0400 (EDT) To: Robert Creager Cc: pgsql-performance@postgresql.org Subject: Re: Huge performance problem between 7.4.1 and 8.0.3 - CS issue? In-reply-to: <20050719105014.00007635@C118181.stortek.com> References: <20050718114952.00004ac5@C118181.stortek.com> <15472.1121709173@sss.pgh.pa.us> <20050719105014.00007635@C118181.stortek.com> Comments: In-reply-to Robert Creager message dated "Tue, 19 Jul 2005 10:50:14 -0600" Date: Tue, 19 Jul 2005 12:54:22 -0400 Message-ID: <7322.1121792062@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.006 tagged_above=0 required=5 tests=AWL X-Spam-Level: X-Archive-Number: 200507/291 X-Sequence-Number: 13532 Robert Creager writes: > Alright. Restarted the 803 database. Cron based vacuum analyze is > running every 5 minutes. vacuum_cost_delay is 0. The problem showed > up after about 1/2 hour of running. I've got vacuum jobs stacked from > the last 35 minutes, with 2 vacuums running at the same time. CS is > around 73k. Hmm, I hadn't thought about the possible impact of multiple concurrent vacuums. Is the problem caused by that, or has performance already gone into the tank by the time the cron-driven vacuums are taking long enough to overlap? regards, tom lane