RESET DATABASE

Syntax

Text description of the illustration reset.gif

Purpose

To reset the target database in the RMAN repository, which means to do either of the following actions:

• Inform RMAN that the SQL statement ALTER DATABASE OPEN RESETLOGS has been executed and that a new incarnation of the target database has been created. Note that if you run the RMAN command ALTER DATABASE OPEN RESETLOGS (not the SQL statement with the same keywords), then RMAN resets the target database automatically so that you do not have to run RESET DATABASE. By resetting the database, RMAN considers the new incarnation as the current incarnation of the database.

• To reset the database to a previous incarnation. Typically, you would reset the incarnation when performing incomplete recovery to a point before a RESETLOGS operation, or when attempting to undo the affects of a RESETLOGS by restoring backups taken before a RESETLOGS.

Restrictions and Usage Notes

• Execute RESET DATABASE only at the RMAN prompt.

• You must be connected to the target database and a recovery catalog.

• You must issue a RESET DATABASE command before you can use RMAN with a target database that has been opened with the SQL statement ALTER DATABASE OPEN RESETLOGS option. If you do not, then RMAN refuses to access the recovery catalog because it cannot distinguish between a RESETLOGS operation and an accidental restore of an old control file. The RESET DATABASE command gives confirmation to RMAN that you issued a RESETLOGS command.

• You cannot specify TO INCARNATION unless the database is started but not mounted. If you mount a control file from an incarnation after the desired incarnation, then RESET DATABASE TO INCARNATION fails because of a control file mismatch. If you mount the control file from the desired incarnation and then run RESET DATABASE TO INCARNATION, then the connection to the target database and recovery catalog fails due to an incarnation mismatch.

Keywords and Parameters

TO INCARNATION primary_key

Changes the incarnation that RMAN considers to be current to an older incarnation. Specify the primary key of the DBINC record for the database incarnation. Obtain the key value using the LIST INCARNATION OF DATABASE command. After you start the instance and issue the RESET DATABASE TO INCARNATION command, then you can mount or restore a control file from the desired incarnation and then run RMAN commands in this incarnation.

Examples

Resetting RMAN to a Previous Incarnation: Example

The following scenario makes an old incarnation of database prod1 current again:

# step 1: obtain the primary key of old incarnation
LIST INCARNATION OF DATABASE PROD1;

List of Database Incarnations
DB Key  Inc Key   DB Name   DB ID       CUR    Reset SCN    Reset Time
------- -------   -------   ------      ---    ----------   ----------
1       2         PROD1     1224038686  NO     1            02-JUL-00
1       582       PROD1     1224038686  YES    59727        10-JUL-00

# step 2: start instance and reset database
SHUTDOWN IMMEDIATE;
STARTUP NOMOUNT;
RESET DATABASE TO INCARNATION 2;

# step 3: restore control file from previous incarnation:
RESTORE CONTROLFILE;

# step 4: shut down and then and mount the database
SHUTDOWN IMMEDIATE
STARTUP MOUNT

# step 5: restore and recover the database to a point before the RESETLOGS
RESTORE DATABASE UNTIL SEQUENCE 1001;
RECOVER DATABASE UNTIL SEQUENCE 1001;

# step 6: make this incarnation the current incarnation:
ALTER DATABASE OPEN RESETLOGS;