BROKER_EVENTHANDLER

Occurs when a task is waiting in the primary event handler of the Service Broker. This should occur very briefly. Information from Microsoft®

Each SQL server instance has a primary event handler thread for processing Service Broker start up/shutdown and timer events. This thread never goes away and is always either waiting for such events or processing them.

This wait type is charged each time Service Broker's primary event handler waits for instance start up/shutdown or any dialog timer events (dialog timeouts) and mirrored routes timeouts.

Wait_time_ms for this wait type should approximately be equal to the interval since instance start up. Waiting_tasks_count merely indicates the number of times the primary event handler had to wait due to absence of any events.

Neither of these two fields in the DMV indicates any performance issue in the engine. If Service Broker is not being used at all (either directly or through DBMail, Event Notification), then max_wait_time_ms and wait_time_ms would approximately be the same and waiting_tasks_count would be really small value. Source: http://blogs.msdn.com/b/sql_service_broker/archive/2008/12/01/service-broker-wait-types.aspx