PFC <lists(at)peufeu(dot)com> writes:
> Index on orders_products( product_id ) and orders_products( order_id ):
> => Same plan
> Note that in this case, a smarter planner would use the new index to
> perform a BitmapAnd before hitting the heap to get the rows.
Considering that the query has no constraint on
orders_products.order_id, I'm not sure what you think the extra index is
supposed to be used *for*.
(Well, we could put orders as the outside of a nestloop and then we'd
have such a constraint, but with 30000 orders rows to process that plan
would lose big.)
(And yes, the planner did consider such a plan along the way.
See choose_bitmap_and.)
regards, tom lane