Re: Bitmap index scans use of filters on available columns

Nicolas Barbier <nicolas.barbier@gmail.com> writes:
> 2015-11-04 Antonin Houska <ah@cybertec.at>:
>> (see expand_indexqual_opclause()), I'm not sure any kind of expansion is
>> possible for '%abc%' which would result in a b-tree searchable condition.

> I think the question is not about using the b-tree for checking the
> condition, but about just retrieving the value for y from the index,
> and just using that to check the condition before fetching the
> corresponding tuple from the heap.

Bitmap index scans only return TID bitmaps, not index tuples; indeed
the underlying index may not store anything recognizable as tuples.
        regards, tom lane