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 1D1545293D for ; Wed, 8 Jun 2005 00:50:42 -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 62210-02 for ; Wed, 8 Jun 2005 03:50:36 +0000 (GMT) Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by svr1.postgresql.org (Postfix) with ESMTP id 2BEC25294C for ; Wed, 8 Jun 2005 00:50:35 -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 j583oYbl026814; Tue, 7 Jun 2005 23:50:34 -0400 (EDT) To: Josh Berkus Cc: pgsql-performance@postgresql.org Subject: Re: Postgresql on an AMD64 machine In-reply-to: <200506072005.47418.josh@agliodbs.com> References: <1118080420.1644.23.camel@penguin1> <20050607202755.GA28361@surnet.cl> <18285.1118178689@sss.pgh.pa.us> <200506072005.47418.josh@agliodbs.com> Comments: In-reply-to Josh Berkus message dated "Tue, 07 Jun 2005 20:05:47 -0700" Date: Tue, 07 Jun 2005 23:50:33 -0400 Message-ID: <26813.1118202633@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: 200506/157 X-Sequence-Number: 12794 Josh Berkus writes: > Not that I've seen in testing so far. Your improvements have, fortunately, > eliminated the penalty for allocating too much shared buffers as far as I can > tell (at least, allocating 70,000 when gains stopped at 15,000 doesn't seem > to carry a penalty), Cool, that's definitely a step forward ;-) > Regarding 2GB memory allocation, though, we *could* really use support for > work_mem and maintenance_mem of > 2GB. Again, let's see some evidence that it's worth putting effort into that. (Offhand it seems this is probably an easier fix than changing the shared-memory allocation code; but conventional wisdom is that really large values of work_mem are a bad idea, and I'm not sure I see the case for maintenance_work_mem above 2Gb either.) regards, tom lane