IPC:ParallelFinish

This wait event occurs in the leader process of a parallel query when it is waiting for all parallel worker processes to shut down cleanly after completing their portion of the work. This wait happens at the end of parallel query execution, during the cleanup and synchronization phase, before the leader can finalize and return results to the client. While typically brief, prolonged ParallelFinish waits may indicate:

Workers stuck due to I/O, locks, or errors,
Resource contention during worker teardown,
System-level process scheduling delays.