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 D80199DC836 for ; Sun, 12 Feb 2006 13:38:51 -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 70376-08 for ; Sun, 12 Feb 2006 13:38:48 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from mailserver.sandvine.com (sandvine.com [199.243.201.138]) by postgresql.org (Postfix) with ESMTP id 5A4C89DC835 for ; Sun, 12 Feb 2006 13:38:46 -0400 (AST) X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Subject: Re: 10+hrs vs 15min because of just one index Date: Sun, 12 Feb 2006 12:37:13 -0500 Message-ID: <2BCEB9A37A4D354AA276774EE13FB8C2BCC338@mailserver.sandvine.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [PERFORM] 10+hrs vs 15min because of just one index Thread-Index: AcYuGi1h+785T92XQWaXH42+LoIHBAB2V/1w From: "Marc Morin" To: "Aaron Turner" , X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.12 required=5 tests=[AWL=0.120] X-Spam-Score: 0.12 X-Spam-Level: X-Archive-Number: 200602/134 X-Sequence-Number: 17120 We've done a lot of testing on large DB's with a lot of "inserts" and have a few comments. The updates are "treated" as a large "insert" as we all know from pg's point of view. We've run into 2 classes of problems: excessing WAL checkpoints and affects of low correlation. WAL log write's full 8K block for first modification, then only changes. This can be the source of "undesireable" behaviour during large batch inserts like this. =20