On 2015-07-24 11:34:22 +0100, Andrew Gierth wrote: > >>>>> "Andrew" == Andrew Gierth <and...@tao11.riddles.org.uk> writes: > > Andrew> The other is that in subquery_planner, the optimization of > Andrew> converting HAVING clauses to WHERE clauses is suppressed if > Andrew> parse->groupingSets isn't empty. (It is empty if there's either > Andrew> no group by clause at all, or if there's exactly one grouping > Andrew> set, which must not be empty, however derived.) This is costing > Andrew> us some optimizations, especially in the case of an explicit > Andrew> GROUP BY () clause; I'll look into this. > > I'm inclined to go with the simplest approach here, which copies the > quals if there are grouping sets. The only way we could safely move a > qual without copying is if we can show that none of the grouping sets is > empty, that is (), and at this point the grouping set list has not been > expanded so it's not trivial to determine that.
I pushed this to both master and 9.5. While this isn't strictly a bugfix, it seemed better to keep the branches the same at this point. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
