Hello, on a machine where starting two processes: perl -e 'while (1) { ; }' I see two processed at 100% CPU, which is expected (with top). Now, if I do: template1=> SELECT COUNT(*) FROM pg_class a, pg_class b, pg_class c; I see only one 100% CPU PostgreSQL process. I read that while PostgreSQL connetions lead to a UNIX process model, which is better for isolation, some operations have been parallelized and can use more than one core/thread. Maybe this specific case was not (yet?) parallelized, or should it be and thus something is issing in my configuration? Thank you. PS: psql (13.16 (Debian 13.16-0+deb11u1))