Hi Alessandro,
Nested Loop (cost=0.00..1017.15 rows=1 width=1146) (actual time=258.648..258.648 rows=0 loops=1) -> Seq Scan on ubicazione (cost=0.00..1011.45 rows=1 width=536) (actual time=0.065..51.617 rows=12036 loops=1) Filter: ((id_ente = 'dmd'::text) AND (allarme IS NULL) AND (manutenzione IS NULL))
The problem seems here. The planner expects one matching row (and that's why it chooses a nested loop), but 12036 rows are matching this condition.
Are you sure that you recentrly ANALYZED the table "ubicazione"? If so, try to increase statistics for the id_ente column.
P.S. There is also an italian mailing list, if you are interested :) Best regards -- Matteo Beccati http://phpadsnew.com http://phppgads.com ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
