This section tells you about resetting your Oracle database after a failure. You normally need to do this if either of the following applies:
· An error occurred in which all copies of the redo log files are lost, but the database file backup is available.
· You performed a complete offline backup or a consistent online backup immediately before the error, such as during a software upgrade.
With this function you can reset the database to a previous consistent state, at the time of either a complete offline or a consistent online backup. If you reset from an online backup, the consistent end point of the backup is used.
This section discusses how to approach whole database reset.
For more information on how to perform a whole database reset, see Whole Database Reset with BR*Tools.
· We recommend you to perform a full offline backup. If the database is running, use SAP tools, otherwise use operating system tools.
· You have the following data available:
Ў The BRBACKUP logs
Ў The data file backups and, if selected, an incremental backup
Ў If restoring from a consistent online backup, the accompanying redo log files that were saved in the same BRBACKUP run
Any types of database files – data, online redo log, control – might be unavailable on disk.
The following graphic shows how a whole database reset works:
1. Select Database Backup phase
BRRECOVER determines the eligible backups using the entries in the BRBACKUP summary log file back<DBSID>.log (return code 0 or 1). The associated detail logs show whether the required data files were in the backup. The selected backup must be a complete offline or a consistent online backup. To minimize the subsequent recovery time, BRRECOVER always suggests the most recent backup.
You can also select an offline or consistent online incremental backup to be restored. In this case, BRRECOVER automatically selects the corresponding full backup to restore all data files.
2. Check Status of Database Files phase
BRRECOVER checks the status of database files to determine which files will be overwritten.
3. Restore Control Files and Offline Redo Log Files phase
BRRECOVER calls BRRESTORE to restore control files. At the same time, offline redo log files are restored if a consistent online backup was selected.
4. Restore Data Files phase
BRRECOVER calls BRRESTORE to restore all the data files to their original location.
5. Apply Incremental Backup phase
If you selected an incremental backup during the Select Database Backups phase, BRRECOVER calls BRRESTORE to restore and apply the selected incremental backup.
6. Apply Offline Redo Log Files phase
If a consistent online backup was selected, BRRECOVER calls SQLPLUS to apply the restored offline redo log files to the database.
7. Open Database phase
During this phase BRRECOVER:
a. Opens the database
b. Creates missing temporary files
c. Checks the status of database files and tablespaces
d. Deletes unnecessary files which are no longer used by the database