SELECT column_name FROM information_schema.columns WHERE table_name = 'citus_stat_activity' AND column_name NOT IN ('leader_pid', 'query_id')
EXCEPT SELECT column_name FROM information_schema.columns WHERE table_name = 'pg_stat_activity'
ORDER BY 1;
 column_name
---------------------------------------------------------------------
 global_pid
 is_worker_query
 nodeid
(3 rows)

SELECT column_name FROM information_schema.columns WHERE table_name = 'pg_stat_activity'
EXCEPT SELECT column_name FROM information_schema.columns WHERE table_name = 'citus_stat_activity'
ORDER BY 1;
 column_name
---------------------------------------------------------------------
 (0 rows)