Re: Should Oracle outperform PostgreSQL on a complex - Mailing list pgsql-performance

From Mark Kirkwood
Subject Re: Should Oracle outperform PostgreSQL on a complex
Date
Msg-id 43A5DCF5.8010604@paradise.net.nz
Whole thread Raw
In response to Re: Should Oracle outperform PostgreSQL on a complex  (Simon Riggs <simon@2ndquadrant.com>)
List pgsql-performance
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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