Received: from localhost (unknown [200.46.204.187]) by postgresql.org (Postfix) with ESMTP id AFC7A9F9E2B for ; Sat, 8 Sep 2007 18:17:34 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.187]) (amavisd-maia, port 10024) with ESMTP id 35788-02 for ; Sat, 8 Sep 2007 18:17:23 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from davinci.ethosmedia.com (server227.ethosmedia.com [209.128.84.227]) by postgresql.org (Postfix) with ESMTP id 0872A9F9B4B for ; Sat, 8 Sep 2007 18:17:26 -0300 (ADT) X-EthosMedia-Virus-Scanned: no infections found Received: from [63.195.55.98] (account josh@agliodbs.com HELO [192.168.2.3]) by davinci.ethosmedia.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 13161173; Sat, 08 Sep 2007 14:21:48 -0700 From: Josh Berkus Organization: PostgreSQL @ Sun To: pgsql-hackers@postgresql.org Subject: Re: WIP patch for latestCompletedXid method of computing snapshot xmax Date: Sat, 8 Sep 2007 14:18:34 -0700 User-Agent: KMail/1.8.2 Cc: Markus Schiltknecht , Tom Lane References: <3018.1189214811@sss.pgh.pa.us> <28198.1189282917@sss.pgh.pa.us> <46E30EB4.7020304@bluegap.ch> In-Reply-To: <46E30EB4.7020304@bluegap.ch> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200709081418.35059.josh@agliodbs.com> X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200709/365 X-Sequence-Number: 107517 Markus, > I've just completed two dbt2 test runs on a mid-level system, with 4GB > RAM and a 7 disk SATA RAID 1+0 w/ BBU. Once with code as of 2007/09/05 > 18:00 (which is *before* the first lazy xid commit) and once with cvs > HEAD (2007/09/08 +latestCompletedXid.patch. Hmmm. Your results are withing the margin of error for DBT2, so they show no real difference. What we need for this is a heavy-read workload, though; on a workload like DBT2 (which is mostly writes) I wouldn't expect lazy-XID to help much. I'll see if I can find something appropriate. Maybe Jan's TPC-W implementation? -- Josh Berkus PostgreSQL @ Sun San Francisco