In many environments, the batch window is a predefined time of
day that VSAM spheres can be offline, unavailable for online CICS® processing.
For example, a batch window can be defined every night between 10:00 PM
and midnight. During the batch window, a number of tasks might be performed
against the offline VSAM data sets, including:
- Backup creation
- Report generation
- Execution of batch jobs against the VSAM data sets
In most scenarios, the batch window is restricted to a predefined time
interval. If an error occurs during one of the tasks run during the batch
window, the time it takes to recover from the error might prevent the completion
of all required tasks before the end of the batch window. In most environments,
this could prove very costly to business.
For example, consider the following scenario:
- An environment has a batch window between 10:00 PM and midnight. During
this time interval, backups of all VSAM spheres must be taken and a batch
job that updates the VSAM spheres must be run. However, in this example scenario,
all backups completed successfully but the batch job encountered an abend
during step six.
Figure 1. Batch window error
To recover from this scenario, the user would have to perform the following
steps:
Figure 2. Batch window error recovery without CICS VR
batch backout
- Restore the VSAM spheres from their latest backups
- Forward recover the VSAM spheres up to the time that the batch job step,
step six, that was being run when the abend occurred started
- Fix the problem that caused the abend
- Continue execution of the batch job, starting at the batch job step, step
six, that was being run when the abend occurred
While this solution successfully recovers the VSAM spheres from the abend
that occurred, for some users the amount of time required to restore and forward
recover the VSAM spheres would cause processing to exceed the allocated batch
window time frame. Therefore some users have elected to use the batch backout
process in preference to forward recovery.
To help avoid missing the batch window time frame, and to ease the process
of recovering from abends that occur during batch processing, you can use
the CICS VR
batch backout function. CICS VR batch backout removes all updates that were
made to VSAM spheres from a batch job step, or multiple steps, if required.
For example, the user could recover from the same batch error that was previously
described by performing the following steps:
Figure 3. Batch window error recovery with CICS VR batch backout
- Use CICS VR
batch backout to remove all updates made by the job step, step six, that was
being run when the abend occurred
- Fix the problem that caused the abend
- Continue execution of the batch job, starting at the batch job step, step
six, that was being run when the abend occurred
Using CICS VR
batch backout allows you to recover from this batch job error without:
- Restoring the VSAM spheres from backups
- Forward recovering the successful updates made by steps 1-5
Removing the steps listed allows for a quicker recovery from the batch
job error. Therefore increasing the chances of successfully completing all
required batch window processing in the allocated batch window time frame.