This read-write INTEGER acts as a bulk-delete action: setting it to the ID of an active poller destroys every row belonging to that poller in rlEventsTable in one operation, while reading it back is meaningless and always returns 0. Admins care because it offers a fast way to tear down all of one script's monitored events instead of destroying rows individually. For example, an admin sets this to poller ID 4 to instantly remove every event that particular monitoring script had registered, rather than setting each row's status to destroy one at a time.