Re: Best way to scan on-disk bitmaps

"Victor Y. Yegorov" <viy@mits.lv> writes:
> I have questions on how to implement on-disk bitmap scan.

I think your best plan might be

1. Be sure that all the indexable WHERE conditions are passed to the  indexscan as indexquals.  This might be,
say,WHEREa = 42 and b = 'foo'
 

2. Within the index AM, form the AND of the relevant bitmaps (here the  ones for a = 42 and b = 'foo').

3. Within the index AM, pick up the TIDs for the remaining one-bits,  and pass them back.

4. Let the existing machinery handle the OR-ing problem as well as  actual fetching of the heap rows.

This can be done without any restructuring of the index AM API.
        regards, tom lane