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 875869DC89B for ; Sun, 18 Dec 2005 18:10:11 -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 13342-09 for ; Sun, 18 Dec 2005 18:10:05 -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 B23A99DC800 for ; Sun, 18 Dec 2005 18:10:01 -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 <0IRP005NBS8RK7@linda-1.paradise.net.nz> for pgsql-performance@postgresql.org; Mon, 19 Dec 2005 11:10:03 +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 52036558E0; Mon, 19 Dec 2005 11:10:02 +1300 (NZDT) Date: Mon, 19 Dec 2005 11:10:01 +1300 From: Mark Kirkwood Subject: Re: Should Oracle outperform PostgreSQL on a complex In-reply-to: <1134901670.2964.140.camel@localhost.localdomain> To: Simon Riggs Cc: Tom Lane , Bruce Momjian , =?ISO-8859-1?Q?P=E5l_Stenslet?= , pgsql-performance@postgresql.org Message-id: <43A5DE39.6080901@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> <43A4C348.7050703@paradise.net.nz> <1134901670.2964.140.camel@localhost.localdomain> X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.319 required=5 tests=[AWL=0.319] X-Spam-Score: 0.319 X-Spam-Level: X-Archive-Number: 200512/444 X-Sequence-Number: 16265 Simon Riggs wrote: > On Sun, 2005-12-18 at 15:02 +1300, Mark Kirkwood wrote: > > >>Yeah - the quoted method of "make a cartesian product of the dimensions >>and then join to the fact all at once" is not actually used (as written) >>in many implementations > > > But it is used in some, which is why I mentioned it. > > I gave two implementations, that is just (1) > > Sorry Simon, didn't mean to imply you shouldn't have mentioned it - was merely opining about its effectiveness.... >>- probably for the reasons you are pointing out. >>I found these two papers whilst browsing: >> >> >>http://www.cs.brown.edu/courses/cs227/Papers/Indexing/O'NeilGraefe.pdf >>http://www.dama.upc.edu/downloads/jaguilar-2005-4.pdf >> >> >>They seem to be describing a more subtle method making use of join >>indexes and bitmapped indexes. > > > Which is the option (2) I described. > Ok - I misunderstood you on this one, and thought you were describing the "star transformation" - upon re-reading, I see that yes, it's more or less a description of the O'Neil Graefe method. best wishes Mark