Received: from maia.hub.org (maia-2.hub.org [200.46.204.251]) by mail.postgresql.org (Postfix) with ESMTP id 942ED1337BC3 for ; Tue, 25 Jan 2011 23:04:34 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.251]) (amavisd-maia, port 10024) with ESMTP id 70733-02-7 for ; Wed, 26 Jan 2011 03:04:26 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id 8450A1337BE8 for ; Tue, 25 Jan 2011 23:03:55 -0400 (AST) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id p0Q33m1F014695; Tue, 25 Jan 2011 22:03:49 -0500 (EST) To: Josh Berkus cc: pgsql-bugs@postgresql.org Subject: Re: Multicolun index creation never completes on 9.0.1/solaris In-reply-to: <4D3F8A9E.8070608@agliodbs.com> References: <4D3F2D10.1020905@agliodbs.com> <21735.1295990515@sss.pgh.pa.us> <4D3F8A9E.8070608@agliodbs.com> Comments: In-reply-to Josh Berkus message dated "Tue, 25 Jan 2011 18:44:46 -0800" Date: Tue, 25 Jan 2011 22:03:48 -0500 Message-ID: <14694.1296011028@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.91 tagged_above=-5 required=5 tests=BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201101/205 X-Sequence-Number: 29227 Josh Berkus writes: > OK, either tape sort is broken or trace_sort is. The larger my > maint_work_mem, the MORE tapes it wants to use: Yeah, that's right. More tapes = better, or at least that was the conclusion we came to some years ago. It doesn't necessarily use all those tapes --- it's hoping it will find that the data sorts into fewer runs than that, and it can go directly to the final merge without any intermediate merge passes. It's conceivable that there's an upper bound to the number of tapes we should try to use, but you really haven't provided any data that would either confirm or refute that idea. regards, tom lane