Metadata Synchronization issues in the Work Item Tracking Object Model
The Work Item Tracking Object Model communicates through SOAP with the Work Item Tracking Web service. The Web service runs on the application tier. The Work Item Tracking Object Model runs on the client. This introduces network latency issues because the client and application tier are almost always on different computers. To minimize the amount of data that is round-tripped, the Work Item Tracking Object Model stores metadata on the client that includes information about FieldDefinitions, WorkItemTypes, team Projects, and classifications.
The Work Item Tracking Object Model updates its metadata cache incrementally only when necessary. Use the following information to verify whether a cache update is needed.
Cache version The version of the cache on the server. This is incremented whenever the cache is updated.
Server GUID The unique identifier for the server. This is different for every server. It also changes when a server is redeployed.
When there is a mismatch in the previous information between the Work Item Tracking Object Model and server metadata cache, the deltas between the two are passed down to the Work Item Tracking Object Model.
The update mechanism for metadata should be transparent to the Work Item Tracking Object Model. The cache refreshes automatically as necessary every time the object model connects to the Web service. However, as a fail-safe, consumers can call RefreshCache to force an update of the client-side cache.