Mario Splivalo <mario.splivalo@xxxxxxxxxx> writes: > Besides PK and uq-constraint indices I have this index: > CREATE INDEX transactions_idx__client_data ON transactions > USING btree (transaction_client_id, transaction_destination_id, > transaction_operator_id, transaction_application_id, > transaction_time_commit) > SELECT <some-columns> FROM transactions WHERE transaction_time_commit > BETWEEN '2009-01-01' AND '2009-01-31 23:59:59'; > The problem is that postgres is never using an index: Hardly surprising --- a search on the index's lowest-order column would require scanning practically all of the index. (If you think about the ordering of the index entries you'll see why.) If this is a typical query then you need a separate index on transaction_time_commit. The fine manual goes into some detail about how to design indexes; http://www.postgresql.org/docs/8.3/static/indexes.html particularly 11.3, 11.5. 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
