Jerry Brenner <jbren...@guidewire.com> writes: > I'm wondering why a sort is required for this query, as the index should be > providing the required ordering to satisfy the ORDER BY clause. Does it > have to do with the IS NULL predicate on the leading key column in the > index?
IS NULL is not seen as an equality condition, no. It's pretty much
of a hack that makes it an indexable condition at all, and we don't
really do any advanced optimization with it.
regards, tom lane
