Hi, At the moment $subject doesn't allow parallelism, because copy.c's pg_plan_query() invocation doesn't set the CURSOR_OPT_PARALLEL_OK flag.
To me that appears to be an oversight rather than intentional. A somewhat annoying one at that, because it's not uncommong to use COPY to execute reports to a CSV file and such. Robert, am I missing a complication? I personally think we should fix this in 9.6 and 10, but I've to admit I'm not entirely impartial, because Citus hit this... Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers