The shutdown assist utility program, DFHCESD

CICS® provides a shutdown assist transaction, that can be run during the first quiesce stage of shutdown. It can be run on a normal or an immediate shutdown.

You specify the name of the shutdown transaction on the SDTRAN system initialization parameter, or on the SDTRAN option of the PERFORM SHUTDOWN and PERFORM SHUTDOWN IMMEDIATE commands. You can also specify that no shutdown assist transaction is to be run. If you do specify that no shutdown assist transaction is to be run, the following processing occurs:

On a normal shutdown, CICS waits for all running tasks to finish before entering the second stage of quiesce. Long running or conversational transactions can cause an unacceptable delay or require operator intervention.
On an immediate shutdown, CICS does not allow running tasks to finish and backout is not performed until emergency restart. This can cause an unacceptable number of units of work to be shunted, and locks to be retained unnecessarily.

The purpose of the shutdown assist transaction is to help solve these problems; that is, to ensure that as many tasks as possible commit or back out cleanly within a reasonable time.

The default shutdown assist transaction is CESD, which starts the CICS-supplied program DFHCESD. DFHCESD attempts to purge and back out long-running tasks using increasingly stronger techniques. It ensures that as many tasks as possible commit or back out cleanly, enabling CICS to shut down in a controlled manner. For information about DFHCESD, and about how to write your own shutdown assist transaction, see Shutdown assist program (DFHCESD).