Re: Index on immutable function call - Mailing list pgsql-general

From A. Kretschmer
Subject Re: Index on immutable function call
Date
Msg-id 20100119102522.GJ29338@a-kretschmer.de
Whole thread Raw
In response to Index on immutable function call  ("Philippe Lang" <philippe.lang@attiksystem.ch>)
List pgsql-general
In response to Philippe Lang :
>
> My goal is to make query...
>
>   select * from indexed_table WHERE data1 >
> this_is_a_long_transformation(data2);
>
> ... as fast as
>
>   select * from indexed_table WHERE data1 > data2;
>
> ... with the help of the index "long_transformation_index".
>

Around 50% of your data comply with your where-condition, i think, this
is the reason why the planner decides for a seq-scan.

Andreas
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Andreas Kretschmer
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