BTW, I just had another thought about reducing the cost of has_parallel_hazard checks, to wit: you already made one pass over the entire query to verify that there's no PARALLEL UNSAFE functions anywhere. If that pass were to also track whether there are any PARALLEL RESTRICTED functions anywhere, then in very many common cases, subsequent tests on portions of the query would not have to do anything, because we'd already know there was nothing to worry about.
regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers