MAN: Point-in-Time Recovery of a Backup From Before Last Resetlogs

MAN: Point-in-Time Recovery of a Backup From Before Last Resetlogs

This Note is valid for 8i, 9i, 10g, 11g Releases 

Problem Description: 
==================== 

You would like to restore a database to a point-in-time, but the backup 
being used is from before the last resetlogs.

The problem is that when a database is opened with resetlogs, the incarnation 
of the database is also reset and RMAN keeps a record of the incarnation of the 
database in the Recovery Catalog.


Problem Explanation: 
==================== 

When we do a point-in-time recovery and open the database with resetlogs, we 
also need to tell RMAN that we are reseting the database incarnation. Therefore 
we use the RESET DATABASE command to direct RMAN to create a new database 
incarnation record in the recovery catalog.  This new incarnation record 
indicates the current incarnation.  RMAN will associate all subsequent backups 
and log archiving done by the target database with the new database incarnation.

If we want to restore the database to a point-in-time before the last 
resetlogs, we need to tell RMAN that our current incarnation needs to be reset 
to the old one. 

 
Problem References: 
=================== 

ORACLE8i BACKUP AND RECOVERY GUIDE

 
Search Words: 
============= 

RESET INCARNATION RECOVER RESETLOGS



Solution Description: 
===================== 

Before we can restore a backup from before the last resetlogs, we need to reset 
the database to the old incarnation number.

Here are the steps to reseting the correct incarnation and restoring the 
database to a point in time before the last resetlogs.

Note: Target database should be nomounted.

1. Start RMAN and connect only to the catalog database.

   % rman catalog rman/rman@rcat

2. Execute the command that lists all the incarnation values for the         
   databases in the recovery catalog.

    RMAN> list incarnation;

List of Database Incarnations
DB Key  Inc Key DB Name  DB ID            CUR Reset SCN  Reset Time
------- ------- -------- ---------------- --- ---------- ----------
1       2       R815     579966833        NO  1          03-MAY-99
224     225     R815     579966833        YES 92402      05-MAY-99

We can see that one of the databases had been open with resetlogs and a new 
incarnation was started (DB_ID 579966833).  We should look at the column 
DATABASE INC KEY. We can see the original incarnation for this database was 2 
and was reset to what is still the current incarnation of 225.  2 is the 
database incarnation that has to be set in order to restore a backup from 
before the last resetlogs.

3. We first need to let RMAN know what database ID we will be dealing 
   with, so we execute the following command:
       
     RMAN> Set dbid 579966833;

4. Now we need to connect to the target instance so we can verify the 
   database ID.

     RMAN> connect target
     RMAN-06005: connected to target database: R815 (DBID=579966833)

5. Since we are connected to both the recovery catalog and target 
   database, we need to tell RMAN to reset the database incarnation to 2. 

   We do this with the following command:

      RMAN> reset database to incarnation 2;

   We can now see that the current incarnation has been set back to 2.
       
      RMAN> list incarnation;

List of Database Incarnations
DB Key  Inc Key DB Name  DB ID            CUR Reset SCN  Reset Time
------- ------- -------- ---------------- --- ---------- ----------
1       2       R815     579966833        YES 1          03-MAY-99
224     225     R815     579966833        NO  92402      05-MAY-99


6.  After resetting the database, issue restore and recover commands to restore 
    and recover the database files from the prior incarnation, then open the database 
    with the RESETLOGS option. You need start from restoring a previous incarnation 
    control file when the database is in nomount state. When the database is reset to 
    the previous incarnation, the catalog will automatically picks up a right control 
    file. After restoring the control file, the database must be mounted for datafiles 
    restore. 

    run {
         set until time 'Jul 8 1999 07:55:00'; # set time to just before data was lost
         allocate channel dev1 type disk;
         shutdown abort;
         startup nomount;
         restore controlfile;
         alter database mount; # mount database after restoring control file
         restore database;
         recover database;
         alter database open resetlogs; # this command automatically resets the database
                                        # so that this incarnation is the new incarnation
    }

   
Solution Explanation: 
===================== 
 
Once we set the database to the prior incarnation, RMAN will allow a restore 
and recover of the database using a backup from before the last resetlogs.
 

Solution References: 
==================== 

Oracle8i Recovery Manager User’s Guide, Release 1 (8.1.6) - Part No. A76990-01
Oracle9i Recovery Manager User’s Guide, Release 1 (9.0.1) - Part No. A9013

For 10g, 11g related issues with Incarnation and FRA ( Fast/Flash Recovery Area )
Please see
(Doc ID 965122.1) RMAN RESTORE FAILS WITH RMAN-06023 BUT THERE ARE BACKUPS AVAILABLE 

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