Re: 1-/2-dimensional indexes for common columns, rationale?

am Wed, dem 26.03.2008, um 15:18:53 +0100 mailte Marinos Yannikos folgendes:
> Hello,
>
> we have several indexes such as:
>
> create index foo1 on bla (a);
> create index foo2 on bla (b);
> create index foo3 on bla (a,b);
>
> They are all used often by frequently used queries (according to
> pg_statio_user_indexes), but we need somewhat higher INSERT/UPDATE
> performance (having tuned most other things) so we'd like to remove some.

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)

Andreas
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Andreas Kretschmer
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