Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> Hmm, good point. It seems like it would be useful to force the
> planner into use the other plan and get EXPLAIN ANALYZE output for
> that for comparison purposes, but off the top of my head I don't know
> how to do that.
The standard way is
begin;
drop index index_you_dont_want_used;
explain problem-query;
rollback;
Ain't transactional DDL wonderful?
(If this is a production system, you do have to worry about the DROP
transiently locking the table; but if you put the above in a script
rather than doing it by hand, it should be fast enough to not be a big
problem.)
regards, tom lane