Deleting Subscriptions
The subscription remains active until its specified life-span expires or it is deleted by the GrooveSubscriptions Delete operation. A subscription's lifetime can be extended by calling the GrooveSubscriptions Update operation. Note that Groove Web Services policies may limit the initial lifetime of a subscription or the amount of time the subscription is extended by the Update operation.
Event subscriptions can be long lived or used for a short period of time. Short-lived subscriptions can be set up for a single application session to provide an application with a convenient way to update displays and keep track of Groove activity. Long-lived subscriptions can span sessions of your application and allow it to monitor activity that has occurred even while the application was inactive. Subscriptions can be set up to last as long as ninety days and can be renewed, basically allowing them to last indefinitely.
How you handle subscription lifetime will generally depend on the nature of your application. If you are subscribing to events for transient purposes only -- for instance to update your UI displays or otherwise monitor Groove activity, you should design your application to delete all outstanding subscriptions before it exits. That way no resources will be tied up when the application is not running.
On the other hand, if your application is used to synchronize an external data store with Groove, you will want the subscriptions to span sessions of your application, so that all Groove activity can be captured. You may then just run your application periodically to update external data. However, an active subscription consumes resources on the Groove web services server, so it is very important that your application include positive provisions to run frequently enough so that the event queue does not become too large. Failure to do so may seriously compromise the operation of the server system.
See Also
Reference
GrooveSubscriptions Web Service
GrooveEvents Web Service