Overview

In the last chapter, you used a DO FORCEJOB statement in an ON/DO block to force a "remedial" job following a job failure. However, rather than run a remedial job following job failure, it is more likely that you will want to correct the problem and then restart the job that failed.

In this chapter, you will learn to use Control-M/Restart to perform job restarts when they become necessary. Before you do, however, you should be clear about the difference between a job rerun and a job restart.

Job rerun is the re-execution of a scheduled job, starting from the beginning. For example, if a job fails, the entire job can be rerun. At best, rerunning a job can waste processing time on already successfully completed job steps; and unless certain precautions are taken, if successful job steps from the prior run performed updates before the job failed, rerunning the job can create problematic results by repeating those updates.

Job restart is the re-execution of a job beginning at a particular step. In general, the results of successful job steps before the failure are utilized, and re-execution continues from the end of the last successful step.

Control-M/Restart automates restart by identifying the step at which to initiate a job restart, and by performing necessary tasks to ensure that job restart is error-free.

Two separate processes are required for Control-M/Restart to restart under Control-M:

• Defining the restart parameters in the Control-M job scheduling definition appropriately, so that restart can be performed if it becomes necessary.
• Activating the restart process when restart becomes necessary.

In this chapter, you will define restart parameters in the job scheduling definition, and then, following job failure and correction of the problem, see and involve yourself in the process of restart.