Prolem wiht long query?

Hi,

I have some trouble with a very long query.

This Query run well :
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select *   from       adresses, liaison_adresse_rubrique as lar0,       liaison_adresse_rubrique as lar1,
liaison_adresse_rubriqueas lar2   where       lar0.refadresse=adresses.ref   and lar0.refrubrique=73   and
lar1.refadresse=adresses.ref  and lar1.refrubrique=151   and lar2.refadresse=adresses.ref   and lar2.refrubrique=170
 

This Query take a lot of time :
-----------------------

select *   from       adresses, liaison_adresse_rubrique as lar0,       liaison_adresse_rubrique as lar1,
liaison_adresse_rubriqueas lar2,       liaison_adresse_rubrique as lar3,       liaison_adresse_rubrique as lar4   where
     lar0.refadresse=adresses.ref   and lar0.refrubrique=73   and lar1.refadresse=adresses.ref   and
lar1.refrubrique=150  and lar2.refadresse=adresses.ref   and lar2.refrubrique=160   and lar3.refadresse=adresses.ref
andlar3.refrubrique=151   and lar4.refadresse=adresses.ref   and lar4.refrubrique=170
 

This Query never finish, and take all my memory (and I have 384Mb)
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select *   from       adresses, liaison_adresse_rubrique as lar0,       liaison_adresse_rubrique as lar1,
liaison_adresse_rubriqueas lar2,       liaison_adresse_rubrique as lar3,       liaison_adresse_rubrique as lar4,
liaison_adresse_rubriqueas lar5,       liaison_adresse_rubrique as lar6   where       lar0.refadresse=adresses.ref
andlar0.refrubrique=73   and lar1.refadresse=adresses.ref   and lar1.refrubrique=148   and lar2.refadresse=adresses.ref
 and lar2.refrubrique=153   and lar3.refadresse=adresses.ref   and lar3.refrubrique=150   and
lar4.refadresse=adresses.ref  and lar4.refrubrique=160   and lar5.refadresse=adresses.ref   and lar5.refrubrique=151
andlar6.refadresse=adresses.ref   and lar6.refrubrique=170
 



Every think is index using hash table.

Is it a limitation of pg?

Do you know another method to do that?

Is it exist an intersect operator in pg (like in oracle)?

Jérome knobl, Lausanne, Switzerland