You'll notice that the subquery version is doing the full join and then the filtering, but the explicitly listed version pushing the filtering into the plan before the join. Is there a way to make the subquery version perform the same optimization?
EXPLAIN ANALYZE SELECT * FROM addressesall WHERE id = ANY (array(SELECT id FROM users WHERE name='A'));
(Tested on 9.0.3)
I just tested that on 8.3.3 and it performed quickly like I expected the other query to, so that did the trick.
