From: Mark Kirkwood <markir@paradise.net.nz>
To: Simon Riggs <simon@2ndquadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Bruce Momjian <pgman@candle.pha.pa.us>
Cc: Pål Stenslet <paal.stenslet@exie.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Should Oracle outperform PostgreSQL on a complex
Date: Mon, 19 Dec 2005 11:10:01 +1300
Message-ID: <43A5DE39.6080901@paradise.net.nz> (raw)
In-Reply-To: <1134901670.2964.140.camel@localhost.localdomain>
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>
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
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To: pgsql-performance@postgresql.org
Cc: markir@paradise.net.nz, simon@2ndquadrant.com, tgl@sss.pgh.pa.us, pgman@candle.pha.pa.us, paal.stenslet@exie.com
Subject: Re: Should Oracle outperform PostgreSQL on a complex
In-Reply-To: <43A5DE39.6080901@paradise.net.nz>
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