Recovering Database Changes with the Batch Backout Utility

The Batch Backout utility processes a backout log file and removes the updates to the IMS databases that were issued from the program that created the log file. The log file is processed in reverse. Database updates can be rolled back either for the entire batch job or back to a specific checkpoint ID.

The input log file to the Batch Backout utility is specified on the BBOLOGI DD statement. The log file must be catalogued in Enterprise Server as follows:

//BBOLOGI DD DSN=HLQ.PRJ01.BBOLOG.DEMO001T,DISP=SHR

You can specify an optional recovery log file using the BBOLOGO DD statement. It too must be catalogued in Enterprise Server, for example:

//BBOLOGO DD DSN=HLQ.PRJ01.BBOLOG.RECOVERY,DISP=(NEW,CATLG,DELETE)

You can use this log output file in the event that the database file needs to be restored to its state before the backout utility was run. In this event, use this recovery log as the input log (BBOLOGI) to a subsequent run of the backout utility.

CAUTION:

it is important to be aware of the existence of the extension logs when backing up the logs or moving them to alternate locations. The recovery log to be created (that is the file associated with ddname BBOLOGO) data file and any extensions associated with it must not exist. In this event, the recovery job terminates with the appropriate error message.