Re: Query performanc issue - too many table?

"Marc Mitchell" <marcm@eisolution.com> writes:
> I am having a problem with the below SQL taking an extreme amount of time
> to run.  The problem is that the explain looks great with all index scans.
> But the query itself takes minutes to run.  The query contains 11 tables.
> We've found that by dropping any one table, performance reverts to being
> nearly instantaneous.

11 tables is the default GEQO threshold, so I'm wondering if the GEQO
planner is missing the best plan.  It's hard to tell much though without
seeing plans for *both* queries you are comparing.  EXPLAIN ANALYZE
output would be much more useful than just EXPLAIN, too.

            regards, tom lane