To delete a data item from the cache structure and free the cache structure resources allocated to that data item, issue the IXLCACHE REQUEST=DELETE_NAME request. With one request you can delete a single data item or multiple data items whose names satisfy a specified character selection pattern. For cache structures allocated in a coupling facility of CFLEVEL=4 or lower, the system deletes the data entry and the directory entry for the data items identified on the request, and invalidates the copies of the data items that are in local cache buffers for all users (including the user who issues the request). The data items are no longer associated with their cast-out classes or storage classes, and the resources allocated to the data item are made available for reuse within the cache structure. Subsequent references to a deleted data item fail until the data item is redefined to the cache structure.

For cache structures allocated in a coupling facility of CFLEVEL=5 or higher, you have the option of specifying the type of resource deletion that is to be performed as well as whether version number comparison is required.

If your protocol relies on external serialization, you need to hold a lock to serialize access to data items. For serialization recommendations and sample scenarios that show how to establish serialization, see Serializing and Managing Access to Shared Data.

Timing and DELETE_NAME Requests

When you issue the DELETE_NAME request, consider the impact of timing issues on serialization. If another user creates a new data item in the cache after you have issued a DELETE_NAME request with criteria that matches the data item but before the request completes, the request might not delete the data item. If you want to ensure that when your request completes, any data item matching your criteria has been deleted from the cache structure, you must hold serialization throughout the request processing. Serialization needs to remain in effect for both the initial request, and any subsequent request restarts that might be required as a result of a timeout, and the scope of the serialization must prevent any other user from creating a new entry that matches the criteria on the DELETE_NAME request.