Results 1 to 2 of 2
  1. #1
    Join Date
    Jun 2009

    Unanswered: softmax 200 : crash recovery

    DB2 is has a transcation which is spanned across 5 log files before it has crashed. Softmax value set on the database is just 200 which means it requires only 2 log files during crash recovery. So does that mean that the transaction which is spanned across 5 log files cannot be recovered during a crash recovery.

  2. #2
    Join Date
    Jun 2003
    Toronto, Canada
    Provided Answers: 1
    No connection between the two statements. It's true that the database will try to ensure that only the two log files' worth of log records will need to be redone during recovery by writing bufferpool pages out to disk when the gap between logged changes and persisted changes exceeds 2 log files in your example (LSN gap page cleaning trigger).

    However, whether the "long" (5 log files long) transaction can be recovered or not depends only on whether it was committed before the crash or not. If it was committed, DB2 will only need to replay 2 log files. If it was not committed, it will still replay 2 log files, but then undo the changes made by the uncommitted transaction, going back 5 log files.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts