Re: new correlation metric - Mailing list pgsql-hackers

From Tom Lane
Subject Re: new correlation metric
Date
Msg-id 14201.1225109887@sss.pgh.pa.us
Whole thread Raw
In response to Re: new correlation metric  (Ron Mayer <rm_pg@cheapcomplexdevices.com>)
Responses Re: new correlation metric
List pgsql-hackers
Ron Mayer <rm_pg@cheapcomplexdevices.com> writes:
> ... I was somewhat surprised that the bitmap cost estimates didn't
> also change much.  Wouldn't the estimated # of data blocks
> read for the bitmap be roughly the same as for the index?

By definition, a bitmap scan's cost isn't affected by index order
correlation.
        regards, tom lane


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