Can postgres make use of both GIN and BTREE indexes in a single query?

Question

Let's say I have GIN index on column A that allows me to filter table fast on that column by appropriate WHERE condition which would be slow without that index. However I would like also to order filtered rows by using ORDER BY statement on, let's say column B. Ordering without index is slow, so I use BTREE index on column B. The problem is that pg don't want to use both indexes - if both WHERE cond on column A and ORDER BY B are present in query, pg uses only GIN index. When I remove WHERE cond from query, then it uses BTREE index on col B.

What I can do to force pg to use both indexes, one to filter rows and second one to order them?

Answer 1

To answer your title question, PostgreSQL can make use of multiple indexes for a "bitmap" scan, but only with Boolean logic. It can't use one to order and the other to filter within the same table scan. It is an interesting idea, though.