"Sgarbossa Domenico" <domenico.sgarbossa@xxxxxxxx> writes: > I guess the right query is: > select distinct on (articolo) articolo,data_ent,prezzo from listini_anagrafici order by articolo, data_ent desc > but it seems that this query runs slowly... about 5/6 seconds. > I've tried adding this index > CREATE INDEX articolo_data_ent ON listini_anagrafici (articoli, data_ent) > but it doesn't helps. That index doesn't match the query ordering. You could do select distinct on (articolo) articolo,data_ent,prezzo from listini_anagrafici order by articolo desc, data_ent desc In more recent versions of Postgres you could make an index with one column ascending and the other descending, but AFAIR 8.1 doesn't have that. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
