If the buffer is not large enough to hold all of the data to be read, an IXLCACHE REQUEST=READ_COSTATS can complete prematurely. When a request completes prematurely, the system returns as much data as the buffer can hold. In the first word of the buffer, the system returns the number of the first and last cast-out classes whose statistics were read.

To restart a prematurely completed request, use the following procedure:

1. Process the cast-out statistics that the system returns. You must process these statistics because the restarted request reuses the buffer.
2. Obtain the number of the last cast-out class whose statistics were read. This number is in the low-order two-bytes of the first word in the buffer. Macro IXLYCCIH maps the first word of the buffer and assigns symbolic names to both the low-order two bytes and the high-order two bytes.
3. Add 1 to the number obtained in step 2, and specify this value on the COCLASSB keyword.
4. Reissue the IXLCACHE REQUEST=READ_COSTATS request. To ensure that you do not alter the intent of the request, the restarted request should specify the same keywords and values (with the exception of the value specified on COCLASSB) as the request that completed prematurely.

A restarted request can also complete prematurely. Restart the request using the procedure described.