An event monitor tracks specific data as the result of an event. For example, starting the database might be an event that causes an event monitor to track the number of users on the system by taking an hourly snapshot of authorization IDs using the database.
Event monitors are activated or deactivated by a statement (SET EVENT MONITOR STATE). A function (EVENT_MON_STATE) can be used to find the current state of an event monitor; that is, if it is active or not active.