What is the CICS VR change accumulation utility?

CICS® VR change accumulation (CA) is the process of consolidating forward recovery log records into a change accumulation data set. CICS VR uses the change accumulation data set in conjunction with the forward recovery log to speed up forward recovery processing.

Change accumulation is a two step process:
  1. You must first create CA batch jobs that define CA groups and identify the spheres that are in each group. When you run one of these CA batch jobs, CA reads the forward recovery log for a certain log range, selects the log records for the spheres in that CA group that are important for forward recovery, and then calls DFSORT to sort these log records. CA saves the last update for each record using the sorted log records. Then CA stores the consolidated records in the CA data set. Every time you run the CA batch job, the change accumulation data set is updated with the information from the next log range. You must perform the following:
    1. Run the CA batch job after a backup is taken for any of the spheres in the CA group.
    2. Set up a CA batch job so that it is regularly submitted with a production planning system, such as Tivoli® Workload Scheduler for z/OS®.

    CA runs in parallel with CICS production runs or VSAM batch logging; so keeping the CA data set as current as possible reduces the amount of log data that must be read and applied to forward recover a VSAM sphere.

  2. The second step occurs when you want to forward recover a VSAM sphere. Use the ISPF panels to restore the backed up version of the sphere and generate the necessary JCL using information in the CICS VR RCDS. The APPLYCA keyword is generated on the RECOVER command. APPLYCA tells CICS VR to apply the records in the CA data set to the restored VSAM sphere, and then to apply the remaining log range from the forward recovery log to pick up the most recent changes.

Concept Concept

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Timestamp icon Last updated: Friday, 7 February 2014


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