Normal Recovery from a Rollback

When you use the Span Accessory, prepare for a rollback by maintaining backup copies of the parameter file that correspond to each run of Span Accessory.

For example, if you anticipate having to roll back up to three days of transactions from your database, then you must maintain the last three days of Span Accessory parameter files.

To prepare for a rollback

  1. Make sure that you have saved backup copies of the Span Accessory parameter file for each time you ran it. Span Accessory stores audit location information in its parameter file and the information is updated each time you run it. Consider saving the parameter files in one of the following ways:
    • If you run Span Accessory several times a day:

      DATA/SPAN/databasename/CONTROL/001

      DATA/SPAN/databasename/CONTROL/002

      DATA/SPAN/databasename/CONTROL/003

    • If you run Span Accessory once a day:

      DATA/SPAN/databasename/CONTROL/FEBRUARY4

      DATA/SPAN/databasename/CONTROL/FEBRUARY5

      DATA/SPAN/databasename/CONTROL/FEBRUARY6

  2. Perform the rollback.
  3. Read the DMSII rollback report to determine the audit location of the rollback point. The report will indicate the AFN (audit file number) and ABSN (audit block serial number) of the rollback point, or earlier.

    Alternatively, if you run Span Accessory before reloading an older parameter file, DBEngine will detect an audit location mismatch and try to find the rollback point in the audit trail. If it is successful, Span Accessory will receive the result code 0120 DATABridge Engine: Database rolled back to AFN=afn ABSN=absn Seg=seg Inx=inx timestamp

  4. Restore the Span Accessory parameter file that corresponds to the rollback point, or earlier.
  5. Remove any Span Accessory output files that were created after the rollback point.
  6. Run the Span Accessory as usual.

    If you get an error similar to either of the following, an audit discontinuity has occurred. See the next procedure, “Manual Span Accessory Recovery from a Rollback.”

    DATABridge Engine: >>> [0033] tablename: Audit location mismatch, subtype = value is wrong. Check for DMS rollback <<<

    DATABridge Engine: >>> [0092] Expected ABSN=nnnn in AUDITnnn at segment nnnn but found ABSN=mmmm <<<