X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 577299DC9F6 for ; Thu, 16 Feb 2006 00:54:58 -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 19571-01 for ; Thu, 16 Feb 2006 00:54:57 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id 1903D9DC9CC for ; Thu, 16 Feb 2006 00:54:55 -0400 (AST) 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 k1G4ss3c023298; Wed, 15 Feb 2006 23:54:54 -0500 (EST) To: "Qingqing Zhou" cc: pgsql-hackers@postgresql.org Subject: Re: qsort again (was Re: [PERFORM] Strange Create Index behaviour) In-reply-to: References: <43F38867.6010701@gpdnet.co.uk> <19510.1140036968@sss.pgh.pa.us> <19779.1140038874@sss.pgh.pa.us> <43F39E53.1020009@gpdnet.co.uk> <20781.1140046109@sss.pgh.pa.us> <23107.1140064820@sss.pgh.pa.us> Comments: In-reply-to "Qingqing Zhou" message dated "Thu, 16 Feb 2006 12:47:50 +0800" Date: Wed, 15 Feb 2006 23:54:54 -0500 Message-ID: <23297.1140065694@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.11 required=5 tests=[AWL=0.110] X-Spam-Score: 0.11 X-Spam-Level: X-Archive-Number: 200602/607 X-Sequence-Number: 79745 "Qingqing Zhou" writes: > "Tom Lane" wrote >> No, I mean I ran the bit of SQL script I gave 100 separate times. > I must misunderstand something here -- I can't figure out that why the cost > of the same procedure keep climbing? No, the run cost varies randomly depending on the random data supplied by the test script. The reason the numbers are increasing is that I sorted them for ease of inspection. regards, tom lane