CQS structure warm start

CQS warm starts both a primary structure and its overflow structure if either the primary structure contains data, or one SRDS contains valid structure checkpoint data and the CQS log contains valid data.

During a structure warm start, CQS determines the status of the structure and initiates a structure recovery if necessary. If a structure recovery is needed, CQS allocates the structure and repopulates it from either the CQS log and the SRDS, which contains valid client data from a previous checkpoint, or from the CQS log by itself.

After a structure warm start has completed, CQS determines whether a future recovery is possible based on the status of the structure recovery data sets and the log stream. If the primary structure contains client data, but neither the SRDS nor the log can be used for future recovery, CQS issues a CQS0009W message.

Recommendation: If CQS issues a CQS0009W message, initiate a structure checkpoint as soon as possible. If a structure checkpoint does not complete successfully and the structure fails, CQS cannot recover the structure.

After a structure warm start, CQS can be cold started or warm started. If the log records needed for the CQS restart have been deleted, you might have to cold start the CQS.