Re: left outer join terrible slow compared to inner join

Thomas Beutin <tyrone(at)laokoon(dot)IN-Berlin(dot)DE> writes:
> Thanks for the suggestion, but the result is close to the original outer
> join without the explicit cross join but far away from the speed of the
> inner join.

> EXPLAIN ANALYZE SELECT DISTINCT pz.l1_id, pz.l2_id, pz.l3_id, pz.l4_id FROM ( ot_adresse AS a CROSS JOIN ot_produkt AS p) LEFT OUTER JOIN ot_kat_prod AS pz ON ( p.p_id = pz.p_id ) WHERE p.a_id = a.id AND a.id = '105391105424941' AND a.m_id = '37';
> NOTICE: QUERY PLAN:

> -> Subquery Scan pz (cost=0.00..1683.51 rows=40851 width=170) (actual time=0.03..485.07 rows=40917 loops=11)
> -> Seq Scan on o_kat_prod (cost=0.00..1683.51 rows=40851 width=170) (actual time=0.02..281.77 rows=40917 loops=11)

Hmm, I don't understand why ot_kat_prod is being treated as a subquery
here. It isn't a view or something is it?

regards, tom lane