Re: [COMMITTERS] pgsql: Install some slightly realistic cost estimation

Mike Rylander <mrylander(at)gmail(dot)com> writes:
> unrelated indexes? Could this bitmapping code be used to combine
> indexes from different tables, say in a large UNION or inherited table
> setup?
> should be true when the implementation is complete.

No, it's only for combining indexes on a single table --- the bitmaps
only store TIDs, which are relative to a particular table. I don't
think there'd be any advantage to extending the technique to handle
multiple tables; the real win comes when you AND or OR overlapping
bitmaps, and there could never be any overlap between two different
tables.

If we had multi-table indexes it'd be a different story of course.

regards, tom lane