Re: 1-/2-dimensional indexes for common columns, rationale? - Mailing list pgsql-performance

From A. Kretschmer
Subject Re: 1-/2-dimensional indexes for common columns, rationale?
Date
Msg-id 20080326152518.GI27264@a-kretschmer.de
Whole thread Raw
In response to Re: 1-/2-dimensional indexes for common columns, rationale?  (Marinos Yannikos <mjy@geizhals.at>)
List pgsql-performance
am  Wed, dem 26.03.2008, um 16:15:20 +0100 mailte Marinos Yannikos folgendes:
> A. Kretschmer schrieb:
> >>create index foo1 on bla (a);
> >>create index foo2 on bla (b);
> >>create index foo3 on bla (a,b);
> >>[...]
> >
> >Which version do you have? Since 8.1 pg can use a so called 'bitmap
> >index scan', because of this feature i guess you don't need the index
> >foo3. (if you have 8.1 or higher)
>
> 8.3.1 - foo3 is being used though in presence of both foo1 and foo2, so
> I'd suppose that it's a better choice even with bitmap index scan
> available...

Maybe...


Andreas
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Andreas Kretschmer
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