Geoff Winkless <pgsqladmin@xxxxxxxx> writes: > But as far as I can see, apart from the absolute extremes, the > index-only scan is _always_ going to be quicker than the index+table > scan. Well, that is a different issue: what does the planner think of an index-only scan as compared to a regular index scan. I suspect that it's pricing the IOS very high because a lot of the table is dirty and therefore will have to be visited even in a nominally index-only scan. You might check whether the plan choice changes immediately after a VACUUM of the table. regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
