Re: index not used with subselect in where clause ?

"Rod Taylor" <rod.taylor@inquent.com> writes:
> Adding a LIMIT 1 in the subplan may also help -- as you only need a
> single match to make it true so additional finds are useless -- it'll
> stop sooner or will be more likely to use an index than a full table
> scan.

I believe this is not necessary; the WHERE EXISTS(...) context is
sufficient to cue the planner that only one tuple will be retrieved,
and it will alter the subselect's plan accordingly.

            regards, tom lane