To recover a database to its status when a backup was made, you do not need an unload file. Only the backup file is required.

The point in time at which a transaction is completed is called a synchronization point. Synchronization point processing that validates a transaction-induced update is called a commit. Synchronization point processing that invalidates a transaction is called a rollback. Recovering a database to a transaction synchronization point is called recovering to the most recent synchronization point before the failure occurred. Because any transaction being processed when the failure occurred (a transaction that had not reached a synchronization point) is invalid, update processing performed by such transactions is not recovered. Figure 7-2 shows the transactions that are recovered.

Figure 7-2 Transactions that are recovered (with recovery to the most recent synchronization point before the failure occurred)

Explanation

Because processing of transactions A and B finished and they reached their synchronization points, the database is recovered to these synchronization points.

Because processing of transactions C and D was ongoing, the processing of these transactions is invalid, and is not recovered.

To recover to the most recent synchronization point before the failure occurred, in addition to backup files, you need the unload log files from which log files are output after a backup was made.