Jonathan Vanasco <postg...@2xlp.com> writes: > This is what I don't understand -- notice the two order_by calls.
> If i run this with an inner and outer order_by, I get ~305ms. (I don't > think I need both, but I wasn't sure if ordering is kept from a subselect ) > If i run this with only the inner, I get ~304ms. > If I run this with only the outer, it's pushing over 10minutes again > i'm wondering if anyone might know why that performance hit would be happening The inner ORDER BY would prevent the planner from flattening the two query levels into one; but as for why it gets a much worse plan after flattening --- insufficient data. https://wiki.postgresql.org/wiki/Slow_Query_Questions regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
