On Mon, May 22, 2006 at 18:38:35 -0400, Tom Lane <[EMAIL PROTECTED]> wrote: > Bruno Wolff III <[EMAIL PROTECTED]> writes: > > On Mon, May 22, 2006 at 10:23:28 +0200, > > Albe Laurenz <[EMAIL PROTECTED]> wrote: > >> In order to (efficiently) process a GROUP BY clause, you need a > >> total ordering on the data type that you group by, i.e. an ordering > >> such that for any two data x and y you have either x < y or x > x > >> or x = y. > > > An equality operator is good enough if the number of unique groups isn't too > > large, so that a hash aggregate plan works efficiently. > > Doesn't help for the case at hand, since point_eq isn't marked hashable > either. It would be good to fix things so that the system doesn't > insist on having the sorting option available, though.
Yeah, I thought about that later on my way home. You need to have a hash function that maps equal values to the same hash bucket or things don't work. ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly