Dynamic Rollback

Sometimes, transactions are performed on the source system in error. Ideally, you would not want them replicated to the target database. So, what can be done?

We can't feasibly shut down our production database and perform a point-in-time recovery, nor can we use flashback on a specific set of transactions. We could set up Event Actions to detect and ignore erroneous transactions, such as DELETE operations without a WHERE clause, but it is impossible to trap every eventuality. Fortunately, since GoldenGate 11g Release 2, a reverse data processing utility is bundled with the software that can back out transactions (once identified) based on the period of time in which they occurred.

The reverse utility is typically employed to undo accidental deletes that have occurred on a source table. Let's see how it works.

Creating process groups and trails for reverse processing

Before we can use the reverse utility, we must create dedicated process groups for input and output trail files...