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 informs RMAN that you issued a RESETLOGS command.
• You cannot specify TO INCARNATION unless the database is started NOMOUNT. 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

Syntax Element	Description
TO INCARNATION primary_key	Changes the current incarnation to an older incarnation. Specify the primary key of the DBINC record for the database incarnation. Run LIST INCARNATION OF DATABASE to obtain the key. After you start the instance and issue RESET DATABASE TO INCARNATION, then you can mount or restore a control file from the desired incarnation and run RMAN commands.

Examples

Resetting RMAN to a Previous Incarnation: Example

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

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

List of Database Incarnations
DB Key  Inc Key DB Name  DB ID            CUR Reset SCN  Reset Time
------- ------- -------- ---------------- --- ---------- ----------
1       2       TRGT     1334358386       NO  154381     OCT 30 2001 16:02:12
1       116     TRGT     1334358386       YES 154877     OCT 30 2001 16:37:39

# step 2: start instance and reset database to incarnation key 2
STARTUP FORCE NOMOUNT;
RESET DATABASE TO INCARNATION 2;

# step 3: restore control file from previous incarnation, then shut down instance 
# and mount control file
RESTORE CONTROLFILE;
STARTUP FORCE MOUNT;

# step 4: restore and recover the database to a point before the RESETLOGS
RESTORE DATABASE UNTIL SCN 154876;
RECOVER DATABASE UNTIL SCN 154876;

# step 5: make this incarnation the current incarnation and then list incarnations:
ALTER DATABASE OPEN RESETLOGS;
LIST INCARNATION OF DATABASE trgt;

List of Database Incarnations
DB Key  Inc Key DB Name  DB ID            CUR Reset SCN  Reset Time
------- ------- -------- ---------------- --- ---------- ----------
1       2       TRGT     1334358386       NO  154381     OCT 30 2001 16:02:12
1       116     TRGT     1334358386       NO  154877     OCT 30 2001 16:37:39
1       311     TRGT     1334358386       YES 154877     OCT 30 2001 17:17:03

Resetting the Database After Incomplete Recovery: Example

This example 
assumes that an incomplete recovery or recovery with a backup control file was 
performed in NOCATALOG mode. Later, RMAN is started in CATALOG mode, but the 
RESYNC command fails because the incarnation has not been reset in the catalog.

% rman target / catalog rman/rman@catdb

Recovery Manager: Release 9.2.0.0.0 - Production

(c) Copyright 2001 Oracle Corporation.  All rights reserved.

connected to target database: TRGT (DBID=1334531173)
connected to recovery catalog database

RMAN> RESYNC CATALOG;

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of resync command on default channel at 11/01/2001 12:00:43
RMAN-20003: target database incarnation not found in recovery catalog

RMAN> RESET DATABASE;

new incarnation of database registered in recovery catalog
starting full resync of recovery catalog
full resync complete