Claudio Freire <klaussfre...@gmail.com> writes: > On Mon, Mar 17, 2014 at 7:01 PM, Jim Nasby <j...@nasby.net> wrote: >> Even better would be if the planner could estimate how bad a plan will >> become if we made assumptions that turn out to be wrong.
> That's precisely what risk estimation was about. Yeah. I would like to see the planner's cost estimates extended to include some sort of uncertainty estimate, whereupon risk-averse people could ask it to prefer low-uncertainty plans over high-uncertainty ones (the plans we typically choose for ORDER BY ... LIMIT queries being great examples of the latter). But it's a long way from wishing that to making it so. Right now it's not even clear (to me anyway) how we'd measure or model such uncertainty. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers