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 11:04:37 +1300
Message-ID: <43A5DCF5.8010604@paradise.net.nz> (raw)
In-Reply-To: <1134928407.2964.177.camel@localhost.localdomain>
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>
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
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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: <43A5DCF5.8010604@paradise.net.nz>
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