When to use the Batch Backout utility

Use the Batch Backout utility in any of the following circumstances.

  • If a batch job fails and you did not request automatic dynamic backout.
  • If a batch job fails and you requested dynamic backout, but the failure was not a pseudo-abend.
  • If you perform an emergency restart of IMS specifying the NOBMP option, and BMPs were active at the time of failure, you must run the utility once for each BMP. If you run the utility before restart completes, you must use the ACTIVE control statement.
  • If you perform an emergency restart of IMS specifying the COLDBASE option, you must run batch backout once for each PSB (including MPPs, BMPs, and mixed mode IFPs) used by an application program that updates a full-function DL/I database, if the PSB was active at the time of the failure.

    You should also run batch backout for each PSB for which there is an in-doubt unit of recovery (UOR). Doing so puts the full-function databases in the same state as the Fast Path databases that are not updated until the commit point. If you choose not to back out an unresolved in-doubt UOR, you must remove it from the RECON backout record.

    If you want to initiate these backouts before restart completes, you must specify the COLDSTART control statement for the Batch Backout utility. You do not need to specify the COLDSTART statement for backouts performed after restart.

    DBRC protects all registered databases affected by in-flight and in-doubt UORs from access by other application programs until their backouts complete, even if the backout does not complete until after a cold start. You must ensure that programs do not access any unregistered databases before their backouts are complete.

Before issuing a /ERESTART COLDSYS command, you must run batch backout at least once using the COLDSTART or ACTIVE control statement. These control statements provide DBRC with the information necessary to protect registered databases in need of backout from erroneous access until the backouts are done.

If a failure occurs in one of the online backouts in a DB/DC or DBCTL subsystem that causes IMS to defer the backout:

Procedure

  1. Resolve the original problem.
  2. Issue the /START DB or UPDATE DB START(ACCESS) command.
  3. Complete the backout with a partial (restartable) backout.

In some cases, the restartable backout can also fail because the information it requires has not been saved. In those cases, you must use the Batch Backout utility. You must also use the utility if IMS defers one of the backout failures past a cold start.