Automatic deletion of temporary storage queues

CICS® can automatically delete nonrecoverable temporary storage queues that have not been referenced recently. To use this feature, you set suitable expiry intervals in the temporary storage models (TSMODEL resource definitions).

Automatic deletion frees storage occupied by temporary storage queues that were not deleted by applications and that are no longer required.

The expiry interval for a temporary storage model applies to the temporary storage queues that are associated with that model. Temporary storage queues use the expiry interval that exists for the TSMODEL resource definition at the time that the queue is created.

By default, the expiry interval is zero, that is, no expiry interval applies to the temporary storage queues. Such queues are never eligible for automatic deletion.

You can set an expiry interval in minutes, up to a maximum of 900,000 minutes (that is 15,000 hours). CICS uses the value rounded up to the nearest multiple of 10 minutes. The interval count begins after each use of the temporary storage queue. If the queue is not used again before the expiry interval is reached, the queue becomes eligible for CICS to delete it automatically. When at least one nonzero expiry interval in at least one TSMODEL resource definition exists, CICS starts to scan the CICS region regularly to find eligible queues. The CICS clean up task scans the temporary storage queues in the CICS region and deletes the queues that are eligible for automatic deletion.

If you change the expiry interval in a TSMODEL resource definition, existing temporary storage queues that match the model are not affected. Those queues continue to use the expiry interval that applied when they were created. If all the TSMODEL resource definitions with a nonzero expiry interval are deleted from a CICS region, CICS stops scanning for expired temporary storage queues.

When the CICS clean up task performs a scan, it issues message DFHTS1605. This message shows the number of temporary storage queues that were scanned and the number that were deleted. If the clean up task ends abnormally, it issues message DFHTS0001, and does not run again until CICS is restarted.

The CICS clean up task cannot delete temporary storage queues if the system has reached TSMAINLIMIT (see TSMAINLIMIT system initialization parameter) and there was an attempt to write to a TS queue such that a TS request lock is held. In this situation, the DFHTS1605 message reports that 0 queues were deleted.