Copying redo log files from a cold backup back into a database is only necessary when redo log files have been lost.

Question

Quizplus · Accepted Answer

Redo log files contain all the changes made to the database since the last checkpoint, so if they are lost, the database cannot recover transactions that were not yet written to the data files. Therefore, copying them from a cold backup may be necessary to restore the database to a consistent state.

Copying Redo Log Files from a Cold Backup Back into a Database