X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 67EE59DC893 for ; Sun, 18 Dec 2005 18:04:47 -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 14786-01 for ; Sun, 18 Dec 2005 18:04:45 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from linda-1.paradise.net.nz (bm-1a.paradise.net.nz [203.96.152.180]) by postgresql.org (Postfix) with ESMTP id 0F01B9DC800 for ; Sun, 18 Dec 2005 18:04:37 -0400 (AST) Received: from smtp-3.paradise.net.nz (tclsnelb1-src-1.paradise.net.nz [203.96.152.172]) by linda-1.paradise.net.nz (Paradise.net.nz) with ESMTP id <0IRP005CFRZQKL@linda-1.paradise.net.nz> for pgsql-performance@postgresql.org; Mon, 19 Dec 2005 11:04:38 +1300 (NZDT) Received: from [192.168.1.11] (218-101-29-79.dsl.clear.net.nz [218.101.29.79]) by smtp-3.paradise.net.nz (Postfix) with ESMTP id 0C73B6BF41B; Mon, 19 Dec 2005 11:04:37 +1300 (NZDT) Date: Mon, 19 Dec 2005 11:04:37 +1300 From: Mark Kirkwood Subject: Re: Should Oracle outperform PostgreSQL on a complex In-reply-to: <1134928407.2964.177.camel@localhost.localdomain> To: Simon Riggs Cc: Tom Lane , Bruce Momjian , =?ISO-8859-1?Q?P=E5l_Stenslet?= , pgsql-performance@postgresql.org Message-id: <43A5DCF5.8010604@paradise.net.nz> MIME-version: 1.0 Content-type: text/plain; format=flowed; charset=ISO-8859-1 Content-transfer-encoding: 7bit X-Accept-Language: en-us, en User-Agent: Mozilla Thunderbird 1.0.6 (X11/20051106) References: <200512170428.jBH4S2W23715@candle.pha.pa.us> <1134810953.2964.117.camel@localhost.localdomain> <8627.1134843222@sss.pgh.pa.us> <43A4E08D.2050708@paradise.net.nz> <1134928407.2964.177.camel@localhost.localdomain> X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.336 required=5 tests=[AWL=0.336] X-Spam-Score: 0.336 X-Spam-Level: X-Archive-Number: 200512/443 X-Sequence-Number: 16264 Simon Riggs wrote: > On Sun, 2005-12-18 at 17:07 +1300, Mark Kirkwood wrote: > >>Tom Lane wrote: >> >> >>>>2. transform joins into subselects, then return subselect rows via an >>>>index bitmap. Joins are performed via a bitmap addition process. >> >>Looks like 8.1 pretty much does this right now: > > > Good analysis. > > 8.1 doesn't do: > - the transforms sufficiently well (you just performed them manually) Absolutely - I was intending to note that very point, but it got lost somewhere between brain and fingers :-) > - doesn't AND together multiple bitmaps to assist with N-way joins > Ah yes - I had overlooked that, good point! Cheers Mark