RECOVERY TYPE | WHEN TO USE | TYPICAL SITUATIONS | PREVENTION |
TIME-BASED | A specific point in time is known |
- Bad data was committed to the database; or
- Important data was dropped. To minimize the data loss and recovery time, the DBA should be notified immediately after the user error occurs.
- You know the approximate time when a non-mirrored online redo log becomes corrupt.
| - Multiplex online redo logs
- Test programs, security, and procedures
|
CANCEL-BASED | A specific archived redo log file is known |
- Your current redo log file or group is lost or corrupt and you cannot use it for recovery.
- You lost archived logs needed for recovery.
|
- Mirror online redo logs
- Make frequent backups and duplex the archived log files.
|
CHANGE-BASED | A specific SCN is known | - You are recovering a database in a distributed environment.
| N/A |
BACKUP CONTROL FILE | Complete Loss of the control file | - You lose all the current control files. You cannot recreate the control file, but you have the backup of the older control file.
- There is a need to restore the database to a certain point in time with a structure different from the current one.
| - Mirror the control file onto a different disk
- Keep a current text version of the control file by issuing the
ALTER DATABASE BACKUP CONTROLFILE TO TRACE; statement. |