En un mensaje anterior, Tom Lane escribió: > Fernando Schapachnik <fernando@xxxxxxxxxxxx> writes: > > Now, combined (sorry for the convoluted query, it is build > > automatically by an app). > > > EXPLAIN SELECT DISTINCT p.id > > FROM partes_tecnicos p, > > rel_usr_sector_parte_tecnico r, active_users u > > WHERE ((r.id_parte_tecnico=p.id AND r.id_usr=u.id AND > > u.login='xxx' AND r.id_sector=p.id_sector_actual AND > > p.id_cola_por_ambito=1) > > OR p.id_cola_por_ambito=1) > > AND p.id_situacion!=6; > > Is this query really what you want to do? Because the OR overrides all > the join conditions, meaning that rows having p.id_cola_por_ambito=1 > AND p.id_situacion!=6 must produce Cartesian products against every > row in each of the other tables. > > I think your SQL-building app is broken. Yes, yes, we found this while working on improving the query. I just wanted to point out that the optimizer was doing a sequential scan in a situation it could unfould de active_users definition, add the login='xxx' clause, and use the index on the users table. Thanks. Fernando.
