Re: Implementing Bitmap Indexes - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Implementing Bitmap Indexes
Date
Msg-id 10262.1107033669@sss.pgh.pa.us
Whole thread Raw
In response to Re: Implementing Bitmap Indexes  (Mike Rylander <mrylander@gmail.com>)
List pgsql-hackers
Mike Rylander <mrylander@gmail.com> writes:
> As a side note, wouldn't the in-memory bitmaps pretty much kill the
> need for multicolumn indexes?  It seems that they would be able to
> join index scans on the same table, and then there would be no need
> for industrial strength cross-column correlation stats.

No, because the ability to do it is not the same as the ability to
predict in advance how many rows will result.
        regards, tom lane


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