After a failover event, which components of SQL databases are retained under database-level protection?

The retention of all user transactions recorded in the transaction log following a failover event is essential because it ensures data consistency and reliability in the event of a database failure. Transaction logs capture all changes made to the database, including inserts, updates, and deletes, allowing for the recovery of data to a specific point in time. This capability is crucial for restoring databases to the state they were in just before the failure, thereby minimizing data loss.

By retaining these transactions, SQL databases can effectively recover and maintain data integrity, making this option vital for database-level protection. This is particularly important in high-availability scenarios where downtime must be minimized, and any potential data loss is unacceptable.

Other components such as hardware configurations or primary operational configurations are not retained by database-level protections in the same manner as transaction logs. They relate more to the physical setup or settings that do not directly influence the data integrity post-failover. Application settings may vary with different server environments and are not explicitly preserved in the database's transaction logs. Therefore, the focus on transaction logs is what makes this answer suitable for understanding the recovery mechanism in SQL databases.