Don't hold your breath waiting for that to change. To do what you're wishing for, we'd have to treat the GROUP BY subquery as if it were an inner indexscan, and push a join condition into it. That's not even possible today.
Thanks! Knowing "that's not a thing" helps; we'll just have to rephrase the query.
Jay -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
