X-Original-To: pgsql-performance@postgresql.org Received: from spampd.localdomain (postgresql.org [64.49.215.8]) by postgresql.org (Postfix) with ESMTP id 3DB48475AE5 for ; Fri, 9 May 2003 09:08:00 -0400 (EDT) Received: from sss.pgh.pa.us (unknown [192.204.191.242]) by postgresql.org (Postfix) with ESMTP id 0E0A0475A80 for ; Fri, 9 May 2003 09:07:59 -0400 (EDT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.12.9/8.12.9) with ESMTP id h49D81U6000152; Fri, 9 May 2003 09:08:01 -0400 (EDT) To: Achilleus Mantzios Cc: pgsql-performance@postgresql.org Subject: Re: An unresolved performance problem. In-reply-to: References: Comments: In-reply-to Achilleus Mantzios message dated "Fri, 09 May 2003 16:11:49 -0200" Date: Fri, 09 May 2003 09:08:00 -0400 Message-ID: <151.1052485680@sss.pgh.pa.us> From: Tom Lane X-Spam-Status: No, hits=-32.3 required=5.0 tests=BAYES_00,EMAIL_ATTRIBUTION,IN_REP_TO,QUOTED_EMAIL_TEXT, REFERENCES,REPLY_WITH_QUOTES autolearn=ham version=2.50 X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 2.50 (1.173-2003-02-20-exp) X-Archive-Number: 200305/113 X-Sequence-Number: 1892 Achilleus Mantzios writes: > On Fri, 9 May 2003, Tom Lane wrote: >> Achilleus Mantzios writes: >>> If so, how can one find the correlation between the ordering >>> of a table and a multicolumn index? >> >> Well, it is surely no better than the correlation of the index's >> first column --- what is that? > it is 1 Well, that's suggestive, isn't it? What about the remaining columns? regards, tom lane