Extra-Partition TS

An extra-partition TS queue lives outside main memory, on disk in the temporary storage file DFHTEMP. It is the durable kind of temporary storage: bigger, slower than memory, but it survives while CICS is up and can be recovered.

What extra-partition means for TS

• "Extra-partition" here means outside the region's main storage. For TS, you get this with the AUXILIARY option on WRITEQ TS.
• The data is kept in DFHTEMP, a VSAM file managed by CICS, so it does not use region memory.
• Auxiliary queues can be much larger than main storage queues, limited by the DFHTEMP file size.
• Like all TS queues, they are still CICS-internal: only programs in the region can read them.

When to use it

• Large scratch data that would waste region memory, such as many formatted screen pages.
• A suspend data set: a task interrupted mid-work writes its incomplete data to an AUXILIARY queue, ends, and later resumes by reading it back.
• Data that must survive a task abend and be picked up again, within the life of the CICS region.
• Queues shared by many tasks where memory pressure is a concern.

How to code it

• Code WRITEQ TS ... AUXILIARY. READQ TS and DELETEQ TS are unchanged.
• The first WRITEQ creates the queue in DFHTEMP; later writes append items with the next item numbers.
• Delete the queue with DELETEQ TS when done, or it stays in DFHTEMP indefinitely.

Example:-