X-Original-To: pgsql-sql-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 394FC9DCB95 for ; Fri, 6 Jan 2006 17:49:10 -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 09395-06 for ; Fri, 6 Jan 2006 17:49:11 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id 96A009DCB8A for ; Fri, 6 Jan 2006 17:49:07 -0400 (AST) 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 k06Ln9lW023073; Fri, 6 Jan 2006 16:49:09 -0500 (EST) To: alex-lists-pgsql@yuriev.com cc: pgsql-sql@postgresql.org Subject: Re: INSERT waiting under heavy load In-reply-to: <20060106201657.GB1890@s2.yuriev.com> References: <20060106184227.GA1890@s2.yuriev.com> <22727.1136580728@sss.pgh.pa.us> <20060106201657.GB1890@s2.yuriev.com> Comments: In-reply-to alex-lists-pgsql@yuriev.com message dated "Fri, 06 Jan 2006 15:16:57 -0500" Date: Fri, 06 Jan 2006 16:49:09 -0500 Message-ID: <23072.1136584149@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.073 required=5 tests=[AWL=0.073] X-Spam-Score: 0.073 X-Spam-Level: X-Archive-Number: 200601/30 X-Sequence-Number: 23819 alex-lists-pgsql@yuriev.com writes: > if the problem is caused by the the acquire lock->modify column->release > lock on the table 1, then why does it increase significantly increase as the > number of entries in the table 3 grows? The simulation maintains pretty much > constant rate of new requests coming to table 3. Are you vacuuming table 1 on a regular basis while you do this? Accumulation of dead tuple versions in table 1 is a pretty severe performance risk in the sort of scenario you are describing. (I'm not sure why it would manifest as transactions showing "INSERT waiting" state though.) regards, tom lane