On Sat, Dec 4, 2010 at 1:35 PM, Marti Raudsepp <marti@xxxxxxxxx> wrote: > On Sat, Dec 4, 2010 at 13:56, Mathieu De Zutter <mathieu@xxxxxxxxxxxx> wrote: >> I have no idea why in some cases the index scan is not considered. >> Does anyone have an idea? > > I guess that it's because the currval() function is volatile -- its > value has to be tested for again each row. > > Try this instead: > SELECT user_id FROM log_event WHERE id = (SELECT CURRVAL('log_event_id_seq')); > > This will assure that there's only one call to currval(). OK, that makes a lot of sense. Your suggestion solves my problem. Thanks! Mathieu -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance