IBM SC34-7012-01 manual Actions taken at transaction failure

1.CICS invokes DFHREST only when RESTART(YES) is specified in a transaction’s resource definition.

2.Ensure that resources used by restartable transactions, such as files, temporary storage, and intrapartition transient data queues, are defined as recoverable.

3.When transaction restart occurs, a new task is attached that invokes the initial program of the transaction. This is true even if the task abended in the second or subsequent unit of work, and DFHREST requested a restart.

4.CICS keeps statistics on the total number of restarts against each transaction.

5.Emergency restart does not restart any user tasks that were in-flight when CICS abnormally terminated. Instead, recovery manager attaches a special task for each in-flight task that had recovery records in the system log at abnormal termination. This task invokes each resource manager to backout recoverable resources.

6.Making a transaction restartable can involve slightly more overhead, because copies of the TCTUA, COMMAREA, and terminal input/output area (TIOA) have to be kept in case the transaction needs to be restarted. For more information about making transactions restartable, see the CICS Customization Guide.

7.In some cases, the benefits of transaction restart can be obtained instead by using the SYNCPOINT ROLLBACK command. See the CICS Distributed Transaction Programming Guide for information about using this command in an MRO environment.

8.A transaction initiated by terminal input is allowed to restart during shutdown, even if the transaction is defined as SHUTDOWN(DISABLED).

Actions taken at transaction failure

The CICS transaction failure program (TFP) is invoked during abnormal transaction termination, unless the transaction is to be restarted.

The TFP is invoked when the following conditions apply:

vThere is a failure during execution and before syncpoint processing has begun.

vThere is a failure during syncpoint processing.

The principal action of the transaction failure program is to send, if possible, an abend message to the terminal connected to the abending transaction. It also sends a message to the CSMT transient data queue.

Except for transaction failures that occur during syncpoint processing, and before sending the message to the CSMT queue, the transaction failure program links to the user-replaceable program error program, DFHPEP. The CICS transaction failure program gives control to DFHPEP through a LINK. This LINK occurs after all program-level abend exit code has been executed by the task that abnormally terminates, but before dynamic transaction backout (if any) has been performed.

Processing operating system abends and program checks

There is a limit to the processing you can attempt after an operating system abend or a program check.

If the program check or abend is associated with any domain other than the application domain, you have no further part in processing the error. If the program check or abend is in the application domain, one of the following can occur:

94CICS TS for z/OS 4.1: Recovery and Restart Guide