Greg Stark <[EMAIL PROTECTED]> writes: > The thing is that these opclasses you're describing are closely related. It > ought to be possible to use a single index to produce results in any of the > four orders you describe.
Wrong --- only two of them. You can't magically swap nulls from one end of the index to the other (and Hannu's flight of fantasy about double indexscans is just a flight of fantasy; it would be solving the problem at entirely the wrong place). > These aren't all related in the same way. They are all desirable properties of an index column, however. In particular, we do have a market for genuine reverse-sort columns, so that you can use a double-column index to get orderings like ORDER BY x ASC, y DESC. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend