Hi, I've already posted something about this trouble, and all I tried didn't worked very well... Here is my tables : CREATE TABLE accord_editeur ( id_regie int4 not null, num_editeur int4 not null, num_site int4 not null, num_emplacement int4 not null, num_campagne int4 not null, num_publicite int4 not null, num_periode int4, par_id_technologie int4 not null, affichage_possible int4 default 0, ponderation_calculee int4, date_pilotage timestamp NULL, id_ct1 int4, PRIMARY KEY(id_regie,num_editeur,num_site,num_emplacement,num_campagne,num_publicite) ); (I've got a primary key on multiple fields because of the complexity of my database.) CREATE TABLE parametre ( id_parametre int4 not null primary key, id_regie int4 NULL , par_id_parametre int4 NULL , type INT4 not null, valeur_str varchar null, valeur_int int4 null, valeur_fl float8 null, valeur_txt varchar, date_pilotage timestamp NULL, id_ct1 int4 ); CREATE INDEX parametre_tracking_idx ON parametre(type, valeur_int); Here is my query : SELECT ae.id_regie, ae.num_campagne, ae.num_publicite, ae.ponderation_calculee * random(), ae.num_periode FROM accord_editeur ae, parametre par WHERE ae.id_regie=1 AND ae.num_editeur = 1494 AND ae.num_site = 1 AND ae.num_emplacement = 1 AND ae.affichage_possible = 1 AND ae.par_id_technologie = par.id_parametre AND par.type = 10 AND par.valeur_int = 1 If I do an Explain I got this : NOTICE: QUERY PLAN: Nested Loop (cost=0.00..15422.73 rows=1 width=56) -> Index Scan using accord_editeur_pkey on accord_editeur ae (cost=0.00..15420.71 rows=1 width=48) -> Index Scan using parametre_tracking_idx on parametre par (cost=0.00..2.02 rows=1 width=8) EXPLAIN Table accord_editeur only have about 500 000 records. Table parametre about 200. So, with Index Scan it is supposed to run fast. To access to the base, I have a connection pooling tool which maintains always 5 connections to the base (to have more doesn't increase performance). But if I launch 100 queries at a single time (which is what my base is going to face), the execution of the queries is too too slow... The server is a bi-PIII 660 with 1GB RAM. During the execution, a top reveal that CPU usage is 100% - about 20% per postmaster ! This server is dedicated to database... I've separated the web server to see what happens... I can't load my base into memory because its data always change and I have to always have the last data to set my parameters for other queries... Has anybody an idea of what is wrong with this query ? I don't have any ideas anymore. Thanks a lot... Guillaume.
