Re: slow query

Ayub Khan <ayub(dot)hp(at)gmail(dot)com> writes:
> I checked all the indexes are defined on the tables however the query seems
> slow, below is the plan. Can any one give any pointers to verify ?

You might try to do something about the poor selectivity estimate here:

> -> Index Scan using
> menu_item_restaurant_id on menu_item a (cost=0.42..177.31 rows=1
> width=87) (actual time=0.130..3.769 rows=89 loops=1)
> Index Cond: (restaurant_id = 1528)
> " Filter: ((active =
> 'Y'::bpchar) AND (is_menu_item_available(menu_item_id, 'Y'::bpchar) =
> 'Y'::bpchar))"
> Rows Removed by Filter: 194

If the planner realized that this'd produce O(100) rows not 1,
it'd likely have picked a different plan. I'm guessing that
the issue is lack of knowledge about what is_menu_item_available()
will do. Maybe you could replace that with a status column?

regards, tom lane