Re: Optimizer problem in 8.1.6

Fernando Schapachnik <fernando(at)mecon(dot)gov(dot)ar> 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.

regards, tom lane