Joe Van Dyk <joe@xxxxxxxxx> writes: > On Fri, Feb 15, 2013 at 7:43 AM, Tom Lane <tgl@xxxxxxxxxxxxx> wrote: >> Try without the useless "is true" bits. > Huh, that did do the trick. Why does "is true" affect the plan? Because "(x = y) IS TRUE" isn't the same as "x = y". (The behavior for nulls is different.) And the planner only knows about using the latter type of condition for indexscans. Since you need it to convert the end_at condition into an indexscan to get a fast plan, you lose. It's conceivable that we could teach the planner about this case, but I haven't seen enough people doing that to make me think it's worth the code space and planner cycles. 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
