Christophe Pettus: All Your GUCs in a Row: max_parallel_workers and max_parallel_workers_per_gather
Neither of these parameters means what its name says. max_parallel_workers_per_gather is the most workers the planner is allowed to request for one plan node, and the planner usually requests fewer. max_parallel_workers is documented as a limit for the whole cluster, and it is enforced by compari…