On Fri, 2013-01-25 at 16:13 +0100, Alexander Farber wrote: > Hi - > > On Thu, Jan 24, 2013 at 8:12 PM, Guillaume Lelarge > <guillaume@xxxxxxxxxxxx> wrote: > > You should better create an index on pref_money(yw, money). It could > > help you get rid of the seqscan and sort operations. > > I've created an index with > > # create index pref_money_money_index on pref_money(money desc); > > and posted the new EXPLAIN output here: > > http://stackoverflow.com/questions/14498974/optimizing-select-count-query-which-often-takes-over-10-seconds > > But it doesn't seem to change much or > am I too unexperienced to see the change? > There's no change because you created an index on money alone, and that change sure didn't give PostgreSQL a chance to do anything better. What I told you before was to create an index on yw, and money, like this : create index pref_money_yw_money_idx on pref_money(yw, money); This should help you to change the plan and, I hope, get better performances. -- Guillaume http://blog.guillaume.lelarge.info http://www.dalibo.com -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
