5 Super Ideas to Restart of Job or Step in JCL

In Mainframe Projects, sometimes due to a problem your batch job will fail. The reasons can be any. It can be logic related or system related.

You will get knowledge on how a step or Job can be restarted and the related logic and how you can write it in a JCL. Also, what happens when you don’t restart a batch job after fail.

RESTART Parameter

RESTART parameter can be coded only in Job statement
So RESTART parameter handles the only job failures
It cannot be used in EXEC or Step

How to handle job-step failure restarts

The RD parameter you can use in both Job and Exec statements
The RD can handle both Job failures and System Failures
When RD=R or RD=RNC, the system will perform automatic restart either job or step

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R	Restart, checkpoints allowed. This option allows the system to automatically restart the execution of a job or job step from the beginning or from the last checkpoint.
RNC	Restart, no checkpoints. This option allows the system to perform an automatic step restart when the job or job step fails. Automatic and deferred checkpoint restarts aren’t allowed.
NR	No automatic restart, checkpoints allowed. This option suppresses automatic restarts but permits deferred checkpoint restarts.
NC	No automatic restart, no checkpoints. This option indicates that the system can’t perform an automatic step restart if the job or job step fails and that checkpoint restarts aren’t allowed.

JCL Check Point Parameter: How to Use it in COBOL/PL1

The CHKPT parameter in the DD statement will allow you to write Checkpoint in a file
CHKP=EOV, when the end of volume arrives during file processing, after the restart, it checks the entry in Checkpoint file and from that point, it continues.
In COBOL, you need to mention the RERUN clause in the I-O-CONTROL section and assigns the DD name. So checkpoint will write into the data set of DD name.
How to use COBOL RERUN Check here

Also Read: How to Skip Steps From Proc

How a Job can RESTART automatically in JES2 and JES3

If the system fails, you can automatically restart a job using a JES control statement.

In a JES2 environment, you use the RESTART parameter on a /*JOBPARM statement to queue the job for re-execution after a system IPL. If a RESTART parameter isn’t coded, N is assumed unless the installation overrides the default during JES2 initialization.

In a JES3 environment, you use the FAILURE parameter on a //*MAIN statement to indicate the recovery option to use if the system fails. If the FAILURE parameter isn’t coded, a default failure option will be assigned based on job class.

RESTART=Y/N

What happens when you do not restart