Robert Haas <robertmhaas@gmail.com> writes:
> On Wed, Apr 8, 2009 at 10:33 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> The main point is that the planner will prefer a bitmap scan for any
>> query that's estimated to return more than quite a small number of rows.
> That makes sense, but what about the nestloop-over-inner-indexscan case?
What about it? The provided patch made no attempt to optimize that
case.
Doing so might well be interesting, but it's not getting done for 8.4.
I think it would be quite an invasive patch --- it's hard to see how to
do it without explicit support at the nestloop join level, so that you
could pipeline the processing of multiple key values coming from the outer
side of the join.
regards, tom lane
