410 receiving change notifications from notification dispatcher 430 are contemplated generally in some embodiments the system consists of storage for change request information subscription table 420 a notification dispatcher 430 which determines if relevant changes have been made and a notifier which passes the notifications to clients service broker 470 determines if a non durable watcher client 410 has disconnected and if so cleans the queue of change notifications belonging to that non durable watcher client 410 service broker 470 also manages other client state information such as information in subscription table 420 in order to keep the subscription table 420 up to date additionally in one embodiment in which durable watchers are supported service broker 470 determines if a watcher client 410 has requested removal of change notifications or termination and performs clean up operations on the subscription table 420 and the notification queue 460 as per those requests fig5 is a flow diagram of the steps taken by the change notification system 400 in tracking changes for clients 410 according to one embodiment as shown in fig5 in a first step 500 the relational database is queried for relevant data modifications in one embodiment this step 500 is only performed when a change has occurred to.