Activity Monitor Showing Long Duration for WAITFOR Using Activity Monitor, I am consistently seeing the following query showing an average duration of over 300 seconds:

WAITFOR(RECEIVE conversation_handle, service_contract_name, message_type_name, message_body 
                FROM ExternalMailQueue INTO @msgs), TIMEOUT @rec_timeout


There don't seem to be any adverse effects on the server, and this query is showing zeros for all other columns.

Is this normal or a cause for concern?
This is a Service Broker process listening to a queue for messages. 300 seconds will be the time out specified in @rec_timeout. See RECEIVE reference in books online.