If a database is restored using before-image dumps, where should the process begin following an interruption?

If a database is restored using before-image dumps, where should the process begin following an interruption?

• A. Before the last transaction
• B. After the last transaction
• C. As the first transaction after the latest checkpoint
• D. As the last transaction before the latest checkpoint

Answer: (A)

Restoring a database using before-image dumps implies that the system will revert to a state prior to the last series of transactions. The key aspect of this process is that it reinstates the database to a specific point in time, specifically before any unintended changes or transactions occurred after the last stable state. Beginning the restoration process before the last transaction ensures that any changes made by that transaction are not included in the restored state. This is crucial for maintaining data integrity and consistency. The goal is to return the database to a point where it is in a known good state, which is invariably prior to the last transaction if any issues arose. Starting the process at a point after the last transaction would mean including changes that may have caused problems, potentially compromising the integrity of the database. Therefore, initiating the restoration before the last transaction is the correct approach to ensure that only validated, intended changes remain in the database.

Restoring a database using before-image dumps implies that the system will revert to a state prior to the last series of transactions. The key aspect of this process is that it reinstates the database to a specific point in time, specifically before any unintended changes or transactions occurred after the last stable state.

Beginning the restoration process before the last transaction ensures that any changes made by that transaction are not included in the restored state. This is crucial for maintaining data integrity and consistency. The goal is to return the database to a point where it is in a known good state, which is invariably prior to the last transaction if any issues arose.

Starting the process at a point after the last transaction would mean including changes that may have caused problems, potentially compromising the integrity of the database. Therefore, initiating the restoration before the last transaction is the correct approach to ensure that only validated, intended changes remain in the database.