Decide if action is needed to correct the situation

If an inconsistent transaction creates an inconsistent database, the following three options are available to you:
  • Leave the networked database in its inconsistent state.
  • Remove the effects of the transaction wherever it was committed, thereby rolling back the entire transaction.
  • Reapply the effects of the transaction wherever it was rolled back, thereby committing the transaction.

You can leave the database in its inconsistent state if the transaction does not significantly affect database data. You might encounter this situation if the application that is performing the transaction can continue as it is, and you decide that the price (in time and effort) of returning the database to a consistent state by either removing the effects or reapplying the transaction is too high.

You are not required to make this decision immediately. You can use the methods described in the following paragraphs to determine what data the transaction was updating and which records are affected.

As you make your decision, consider that no automatic process or utility can perform a rollback of a committed transaction or can commit part of a transaction that has been rolled back. The following paragraphs describe how to look through the database server message log and the logical log to locate affected records. Without detailed knowledge of the application, messages are not enough to determine what has happened. Based on your knowledge of your application and your system, you must determine whether to roll back or to commit the transaction. You must also program the compensating transaction that performs the rollback or the commit.

Copyright© 2018 HCL Technologies Limited