Assigning a Changed Data Item to a Cast-Out Class

Each time you write a changed data item (CHANGED=YES) to the cache structure, you must assign the data item to a cast-out class. Specify the cast-out class on the COCLASS keyword.

You can define the total number of cast-out classes on the IXLCONN macro. The first user who connects to the structure determines the number of cast-out classes for the structure. Cast-out classes are numbered consecutively from 1 to n where n is the number of cast-out classes specified on IXLCONN.

The data item remains assigned to this cast-out class until one of the following events occur:

A subsequent WRITE_DATA request for the data item assigns a different cast-out class.
A CASTOUT_DATA request casts out the data item from the cache structure, and you issue the UNLOCK_CASTOUT request to release the cast-out lock. (You can issue UNLOCK_CASTOUT and specify that the system remark the data entry as changed, in which case, the data item remains associated with the storage class to which it was assigned. See Changing the Directory Entry for the Data Item.)
A subsequent DELETE_NAME request deletes the data item from the cache structure.

For information on the selection and use of cast-out classes, see Casting out Data Items and Reclaim Processing.