"WARNING: Files may exist in %s that are not known to database."
*Cause: One of the following events caused this:
1. A database crash happened during file creation.
2. A backup control file was restored.
3. The control file was re-created.
4. DB_RECOVERY_FILE_DEST has previously been enabled and then disabled.
*Action: Use RMAN command CATALOG RECOVERY AREA to re-catalog any such
files. If the file header is corrupted, then delete those files
using an OS utility.
Do not use messages 19817; it is used for simulating lock failure
Do not use messages 19818; it is used for space reclamation before backup
Do not use messages 19819; it is used to disable clearing file name