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

From Marinos Yannikos
Subject Re: 1-/2-dimensional indexes for common columns, rationale?
Date
Msg-id 47EA6888.2050506@geizhals.at
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In response to Re: 1-/2-dimensional indexes for common columns, rationale?  ("A. Kretschmer" <andreas.kretschmer@schollglas.com>)
Responses Re: 1-/2-dimensional indexes for common columns, rationale?
Re: 1-/2-dimensional indexes for common columns, rationale?
List pgsql-performance
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...

-mjy



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