Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Alvaro Herrera wrote:
>> Is there a reason sort the pages before scanning them?  The result won't
>> come out sorted one way or the other.
> I think the goal would be to hit the heap in sequential order as much as
> possible.
Exactly.  Also, it'll be harder to AND or OR two bitmaps together if you
don't presort their pages.  (I think the hash representation could do OR
without presort, but not AND.)
        regards, tom lane