Changing EBS Datasource APPS Password in OBIA/BIAPPS

Changing EBS Datasource APPS Password in OBIA/BIAPPS

Step 1 Drop and recreate Database Link with New APPS Password
Drop DBLINK
DROP PUBLIC DATABASE LINK "ERPPROD.WORLD@DSN_90";

Create New DBLINK
CREATE PUBLIC DATABASE LINK "ERPPROD.WORLD@DSN_90"
CONNECT TO APPS
IDENTIFIED BY newpassword
USING 'ERPPROD';

Step 2 Update EBS Datasource with new APPS Password in BI Configuration Manager.
To update the new password in source system (EBS Datasource).
Login to BI Application Configuration Manager  http://bi.mydomain.com:9704/biacm
Click on Define Business Intelligence Applications Instance

Click on Edit Button

Click Next

In the Edit Connection Details, Update new Apps Password and Click on Test

Save and Close the Window

Step 3 Update ODI EBS DataSource with new APPS Password
Login the ODI studio
Update apps password for ODI_DS Data source

Update apps password for ERPPROD Data source

Step 4 Update new APPS Password in Repository (RPD) file
Required for analytics 

Login to BI Administration Tool
Open Repository online

Select Oracle EBS OLTP in the Physical Layer

Right Click on Oracle EBS OLTP and select Properties

Click Yes for Check-Out

Select Oracle EBS OLTP InitBlock Connection Pool and Click Edit Button

Click Yes for Check-Out

Type new apps Password  and click Ok

Changing Weblogic Password in OBIEE

Changing Weblogic Password in OBIEE

1. Go to the WebLogic Administration Console (http://hostname:7001/console).

2. Navigate Security Realm > Users and Groups > weblogic > passwords

3. Change the password for weblogic and save.

4. Navigate bifoundation_domain > Security > EmbeddedLDAP

Press "Lock & Edit."
Check the option "Refresh Replica At Startup" and save.
Press "Activate Changes."

This option "Refresh Replica At Startup" described as "Specifies whether the embedded LDAP server in a Managed Server should refresh all replicated data at boot time. This setting is useful if you have made many changes when the Managed Server was not active, and you want to download the entire replica instead of having the Administration Server push each change to the Managed Server." in the documentation.

5. Stop Admin Server.

6. Delete boot.properties from the following directories.
<MIDDLEWARE_HOME>/user_projects/domains/bifoundation_domain/servers/AdminServer/security
<MIDDLEWARE_HOME>/user_projects/domains/bifoundation_domain/servers/bi_server1/security

7. Create a new boot.properties file and placed under the above directories:
username=weblogic
password=mypassword
(Note: Please, replace "mypassword" with the actual password that you want to set.)
For further information on boot.properties, please check the Note 1265834.1 How To Start WebLogic Admin And OBIEE 11g Managed Servers Without Prompting Administrator Username And Password On Unix Environments.
Once the Admin Server or bi_server1 is started for the first time, credentials in the boot.properties file are automatically encrypted.

8. Start Admin Server. Admin Server has been started with a new password for weblogic.

9. Start bi_server1.

10. Start opmn components.

Reference:
OBIEE 11g: bi_server1 Failed to Start After Changing Weblogic User Password (Doc ID 2223465.1)
OBIA 11g: How to Change BI Applications System Account Passwords (Doc ID 1613764.1)

Backup and Recovery Scenarios

Backup and Recovery Scenariosa) Consistent backups

A consistent backup means that all data files and control files are consistent  to a point in time. I.e. they have the same SCN. This is the only method of  backup when the database is in NO Archive log mode.

b) Inconsistent backups
An Inconsistent backup is possible only when the database is in Archivelog mode.  We must apply redo logs to the data files, in order to restore the database to a consistent state.  Inconsistent backups can be taken using RMAN when the database is open.
Inconsistent backups can also be taken using other OS tools provided the tablespaces (or database) is put into backup mode.
ie: SQL> alter tablespace data begin backup;
    SQL> alter database begin backup; (version 10 and above only)

c) Database Archive mode
The database can run in either Archivelog mode or noarchivelog mode.  When we first create the database, we specify if it is to be in Archivelog  mode. Then in the init.ora file we set the parameter log_archive_start=true  so that archiving will start automatically on startup.
If the database has not been created with Archivelog mode enabled, we can  issue the command whilst the database is mounted, not open.
SQL> alter database Archivelog;.
SQL> log archive start
SQL> alter database open;
SQL> archive log list
This command will show us the log mode and if automatic archival is set.
 
d) Backup Methods
Essentially, there are two backup methods, hot and cold, also known as online and offline, respectively. A cold backup is one taken when the database is shutdown. The database must be shutdown cleanly.  A hot backup is on taken when the database is running. Commands for a hot backup:
For non RMAN backups:
1. Have the database in archivelog mode (see above)
2. SQL> archive log list
--This will show what the oldest online log sequence is. As a precaution, always keep the all archived log files starting from the oldest online log sequence.
3. SQL> Alter tablespace tablespace_name BEGIN BACKUP;
or SQL> alter database begin backup (for v10 and above).
4. --Using an OS command, backup the datafile(s) of this tablespace.
5. SQL> Alter tablespace tablespace_name END BACKUP
--- repeat step 3, 4, 5 for each tablespace.
or SQL> alter database end backup; for version 10 and above
6. SQL> archive log list
---do this again to obtain the current log sequence. make sure that we have a copy of this redo log file.
7. So to force an archived log, issue
SQL> ALTER SYSTEM SWITCH LOGFILE
A better way to force this would be:
SQL> alter system archive log current;
8. SQL> archive log list
This is done again to check if the log file had been archived and to find the latest archived sequence number.
9. Backup all archived log files determined from steps 2 and 8.
10. Back up the control file:
SQL> Alter database backup controlfile to 'filename'
For RMAN backups:
see Note.<>  RMAN - Sample Backup Scripts 10g
or the appropriate RMAN documentation.

e) Incremental backups
These are backups that are taken on blocks that have been modified since the last backup. These are useful as they don't take up as much space and time. There are two kinds of incremental backups Cumulative and Non cumulative.
Cumulative incremental backups include all blocks that were changed since the  last backup at a lower level. This one reduces the work during restoration as  only one backup contains all the changed blocks.
Noncumulative only includes blocks that were changed since the previous backup  at the same or lower level.
Using rman, we issue the command "backup incremental level n"
Oracle v9 and below RMAN will back up empty blocks, oracle v10.2 RMAN will not back up empty blocks

f) Support scenarios
When the database crashes, we now have a backup. We restore the backup and
then recover the database. Also, don't forget to take a backup of the control
file whenever there is a schema change.

RECOVERY SCENARIOS

Note: All online datafiles must be at the same point in time when completing recovery;
There are several kinds of recovery we can perform, depending on the type of  failure and the kind of backup we have. Essentially, if we are not running in archive log mode, then we can only recover the cold backup of the database and we will lose any new data and changes made since that backup was taken. If, however, the database is in Archivelog mode we will be able to restore the database up to the time of failure. There are three basic types of recovery:

1. Online Block Recovery.
This is performed automatically by Oracle.(pmon) Occurs when a process dies  while changing a buffer. Oracle will reconstruct the buffer using the online  redo logs and writes it to disk.

2. Thread Recovery.
This is also performed automatically by Oracle. Occurs when an instance  crashes while having the database open. Oracle applies all the redo changes  in the thread that occurred since the last time the thread was checkpointed.

3. Media Recovery.
This is required when a data file is restored from backup. The checkpoint count in the data files here are not equal to the check point count in the  control file.
Now let's explain a little about Redo vs Undo.
Redo information is recorded so that all commands that took place can be  repeated during recovery. Undo information is recorded so that we can undo changes made by the current transaction but were not committed. The Redo Logs  are used to Roll Forward the changes made, both committed and non- committed  changes. Then from the Undo segments, the undo information is used to
rollback the uncommitted changes.
Media Failure and Recovery in Noarchivelog Mode
In this case, our only option is to restore a backup of Oracle files. The files we need are all datafiles, and control files.  We only need to restore the password file or parameter files if they are lost or are corrupted.
Media Failure and Recovery in Archivelog Mode
In this case, there are several kinds of recovery we can perform, depending on what has been lost.

The three basic kinds of recovery are:
1. Recover database - here we use the recover database command and the database must be closed and mounted. Oracle will recover all datafiles that are online.

2. Recover tablespace - use the recover tablespace command. The database can be open but the tablespace must be offline.

3. Recover datafile - use the recover datafile command. The database can be  open but the specified datafile must be offline.
Note: We must have all archived logs since the backup we restored from,  or else we will not have a complete recovery.

a) Point in Time recovery:
A typical scenario is that we dropped a table at say noon, and want to recover it. We will have to restore the appropriate datafiles and do a point-in-time  recovery to a time just before noon.
Note: We will lose any transactions that occurred after noon.  After we have recovered until noon, we must open the database with resetlogs. This is necessary to reset the log numbers, which will protect the database  from having the redo logs that weren't used be applied.
The four incomplete recovery scenarios all work the same:
Recover database until time '1999-12-01:12:00:00';
Recover database until cancel; (we type in cancel to stop)
Recover database until change n;
Recover database until cancel using backup controlfile;
Note: When performing an incomplete recovery, the datafiles must be online. Do a select * from v$recover_file to find out if there are any files  which are offline. If we were to perform a recovery on a database which has  tablespaces offline, and they had not been taken offline in a normal state, we  will lose them when we issue the open resetlogs command. This is because the data file needs recovery from a point before the resetlogs option was used.

b) Recovery without control file
If we have lost the current control file, or the current control file is  inconsistent with files that we  need to recover, we need to recover either by using a backup control file command or create a new control file. We can also recreate the control file based on the current one using the  'SQL> backup control file to trace' command which will create a script for we to  run to create a new one.  Recover database using backup control file command must be used when using a  control file other that the current. The database must then be opened with
resetlogs option.

c) Recovery of missing datafile with rollback segments
The tricky part here is if we are performing online recovery. Otherwise we can just use the recover datafile command. Now, if we are performing an  online recovery, we will need to create a new undo tablespace to be used.  Once the old tablespace has been recovered it can be dropped once any uncommitted  transactions have rolled back.

d) Recovery of missing datafile without undo segments
There are three ways to recover in this scenario, as mentioned above.
1. recover database;
2. recover datafile 'c:\orant\database\usr1orcl.ora';
3. recover tablespace user_data;

e) Recovery with missing online redo logs
Missing online redo logs means that somehow we have lost our redo logs before  they had a chance to archived. This means that crash recovery cannot be  performed, so media recovery is required instead. All datafiles will need to be restored and rolled forwarded until the last available archived log file is applied. This is thus an incomplete recovery, and as such, the recover
database command is necessary.
As always, when an incomplete recovery is performed, we must open the database with resetlogs.
Note: the best way to avoid this kind of a loss, is to mirror online log files.

f) Recovery with missing archived redo logs
If archives are missing, the only way to recover the database is to restore from latest backup. We will have lost any uncommitted
transactions which were recorded in the archived redo logs. Again, this is why  Oracle strongly suggests mirroring online redo logs and duplicating copies  of the archives.

g) Recovery with resetlogs option
Reset log option should be the last resort, however, as we have seen from above, it may be required due to incomplete recoveries. (recover using a backup control file, or a point in time recovery). It is imperative that we backup up the database immediately after we have opened the database with reset logs.  It is possible to recover through a resetlogs, and made easier with Oracle V10, but easier
to restore from the backup taken after the resetlogs

h) Recovery with corrupted undo segments.
If an undo segment is corrupted, and contains uncommitted system data we may not be able to open the database.
The best alternative in this situation is to recover the corrupt block using the RMAN blockrecover command next best would be to restore the datafile from backup and do a complete recovery.
If a backup does not exist and If the database is able to open (non system object) The first step is to find out what object is causing the rollback to appear corrupted. If we can determine that, we can drop that object.
So, how do we find out if it's actually a bad object?
1. Make sure that all tablespaces are online and all datafiles are online. This can be checked through via the v$recover_file view.

2. Put the following in the init.ora:
event = "10015 trace name context forever, level 10"
This event will generate a trace file that will reveal information about the  transaction Oracle is trying to roll back and most importantly, what object  Oracle is trying to apply the undo to.
Note: In Oracle v9 and above this information can be found in the alert log.
Stop and start the database.

3. Check in the directory that is specified by the user_dump_dest parameter (in the init.ora or show parameter command) for a trace file that was  generated at startup time.

4. In the trace file, there should be a message similar to: error recovery tx(#,#) object #.
TX(#,#) refers to transaction information.
The object # is the same as the object_id in sys.dba_objects.

5. Use the following query to find out what object Oracle is trying to perform recovery on.
select owner, object_name, object_type, status
from dba_objects where object_id = <object #>;

6. Drop the offending object so the undo can be released. An export or relying on a backup may be necessary to restore the object after the corrupted undo segment is released.
 
i) Recovery with System Clock change.
We can end up with duplicate timestamps in the datafiles when a system clock  changes. This usually occurs when daylight saving comes into or out of the picture. In this case, rather than a point in time recovery, recover to a specify log or SCN
 
j) Recovery with missing System tablespace.
The only option is to restore from a backup.
 
k) Media Recovery of offline tablespace
When a tablespace is offline, we cannot recover datafiles belonging to this  tablespace using recover database command. The reason is because a recover database command will only recover online datafiles. Since the tablespace is  offline, it thinks the datafiles are offline as well, so even if we  recover database and roll forward, the datafiles in this tablespace will not be touched.  Instead, we  need to perform a recover tablespace command. Alternatively, we could restored the datafiles from a cold backup, mount the database and select  from the v$datafile view to see if any of the datafiles are offline. If they are, bring them online, and then we can perform a recover database command.
 
l) Recovery of Read-Only tablespaces
If we have a current control file, then recovery of read only tablespaces is  no different than recovering read-write files. The issues with read-only tablespaces arise if we have to use a backup control file. If the tablespace is in read-only mode, and hasn't changed to read-write since the last backup, then we will be able to media recovery using a backup control file by taking the tablespace offline. The reason here is that when we are using the backup control file, we must open the database with resetlogs. And we know that Oracle wont let us read files from before a resetlogs was done. However, there is an exception with read-only tablespaces. We will be able to take the datafiles online after we have opened the database.
When we have tablespaces that switch modes and we don't have a current control file, we should use a backup control file that recognizes the tablespace in  read-write mode. If we don't have a backup control file, we can create a new  one using the create controlfile command.  Basically, the point here is that we should take a backup of the control file every time we switch a tablespaces mode.

RAC Backup, Restore and Recovery using RMAN

RAC Backup, Restore and Recovery using RMAN

Following Example is for a 2-node Oracle RAC Cluster.

The logs are being archived to their respective node.

We are allocating channels to each node to enable the autolocate feature of RMAN in a RAC env.

1. Verify the databases are in archivelog mode and archive destination.

a. NODE 1: thread 1

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u02/app/oracle/product/11.2.0/dbs/arch
Oldest online log sequence     20
Next log sequence to archive   21
Current log sequence           21

 b. NODE 2: thread 2

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /u02/app/oracle/product/11.2.0/dbs/arch
Oldest online log sequence     8
Next log sequence to archive   9
Current log sequence           9

2. Verify connectivity to the target nodes and catalog if used.

$ setenv TNS_ADMIN $ORACLE_HOME/network/admin
$ sqlplus /nolog
SQL> connect sys/pwd@node1 as sysdba
SQL> connect sys/pwd@node2 as sysdba
SQL> connect rman/rman@rcat

3. Set your testing areas.

Testing HOME for logs:  /u02/home/usupport/rman

Backups HOME Location:  /rman/V112

4. Connect using RMAN to verify and set the controlfile persistent configuration. 

The controlfiles are shared between the instances so configuring the controlfile on node 1 also sets it for all nodes in the RAC cluster.

* Always note the target DBID
    connected to target database: V112 (DBID=228033884)

*  Default Configuration

RMAN> SHOW ALL;
    CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
    CONFIGURE BACKUP OPTIMIZATION OFF; # default
    CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
    CONFIGURE CONTROLFILE AUTOBACKUP ON;
    CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
    CONFIGURE DEVICE TYPE DISK PARALLELISM 1; # default
    CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
    CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
    CONFIGURE MAXSETSIZE TO UNLIMITED; # default
    CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/u02/app/oracle/product/11.2.0/dbs/snapcf_V11201.f'; # default

*Configuring Channels to Use a Specific Node

To configure one RMAN channel for each policy-managed Oracle RAC database instance, use the following syntax:

CONFIGURE CHANNEL DEVICE TYPE disk CONNECT 'SYS/RAC@NODE1';'
CONFIGURE CHANNEL DEVICE TYPE disk CONNECT ''SYS/RAC@NODE2';

 5. Make a backup using the new persistent configuration parameters.

*  Backup database with differential incremental 0 and then archived logs   using the delete input option.

BACKUP INCREMENTAL LEVEL 0 FORMAT '/rman/V112/%d_LVL0_%T_%u_s%s_p%p' DATABASE;
BACKUP ARCHIVELOG ALL FORMAT '/rman/V112/%d_AL_%T_%u_s%s_p%p'DELETE INPUT;

* Backup again using differential incremental level 1

     BACKUP INCREMENTAL LEVEL 1 FORMAT '/rman/V112/%d_LVL1_%T_%u_s%s_p%p' DATABASE;

     BACKUP ARCHIVELOG ALL FORMAT '/rman/V112/%d_AL_%T_%u_s%s_p%p' DELETE INPUT;

* To simplify this you can also use PLUS ARCHIVELOG 

BACKUP INCREMENTAL LEVEL 0 FORMAT '/rman/V112/%d_LVL0_%T_%u_s%s_p%p'
DATABASE PLUS ARCHIVELOG FORMAT '/rman/V112/%d_AL_%T_%u_s%s_p%p' DELETE INPUT;

 This uses a different algorithm than backup database and backup archivelog in separate commands, the algorithm for PLUS ARCHIVELOG is:

     1. Archive log current
     2. Backup archived logs
     3. Backup database level 0
     4. Archive log current
     5. Backup any remaining archived log created during backup

6. Backupset maintenance using the configured retention policy

RMAN> LIST BACKUP SUMMARY;
RMAN> LIST BACKUP BY DATAFILE;
RMAN> LIST BACKUP OF DATABASE;
RMAN> LIST BACKUP OF ARCHIVELOG ALL;
RMAN> LIST BACKUP OF CONTROLFILE;

These above can be enhanced with the "until time" clause as well as the archivelog backups using "not backed up x times" to cut down on  many copies of a log in several backup sets.
Then continuing with SMR  Server Managed Recovery use the change archivelog from...until...delete  to remove old logs no longer needed on disk.

To check/delete obsolete backups  or archivelogs we use:

RMAN> REPORT OBSOLETE;

RMAN> DELETE OBSOLETE;
         or
RMAN> DELETE NOPROMPT OBSOLETE;

To check the database files:

RMAN> REPORT SCHEMA; 

7. Restore and Recover

Complete Recovery

With the database mounted on the node1 and no-mount on node2 connect to the target and catalog using RMAN.

      rman target / catalog rman/rman@rcat

    This script will restore and recover the database completely and open the database in read/write mode.  

run {
         RESTORE DATABASE;
         RECOVER DATABASE;
         ALTER DATABASE OPEN;
}

Incomplete Recovery

If you are using instance registration the database must be mounted to register with the listener. This means you must use the current controlfile for restore and recovery or setup a dedicated listener if not  already done. RMAN requires a dedicated server connection and does not work with using instance registration before mounting the controlfile.  Using the autobackup controlfile feature requires the DBID of the  TARGET database. It must be set when the database is not mounted and only the controlfile and spfile (from 9.2) can be restored this way.

    1.Shutdown node1 and node2

    2. Startup no-mount node2 and node1

    3.Start rman and restore the controlfile from autobackup:

     rman trace reco1.log

RMAN> CONNECT CATALOG rman/rman@rcat

RMAN> SET DBID=228033884;

RMAN> CONNECT TARGET

RMAN>  restore controlfile;

   4. If no catalog is used, you can restore the controlfile from autobackup

     % rman trace recocf.log

RMAN> SET DBID=228033884;

RMAN> CONNECT TARGET /

RMAN> RUN
{

 SET CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE disk TO '/rman/V112/%F';
       ALLOCATE CHANNEL d1 DEVICE TYPE disk;
       RESTORE CONTROLFILE FROM AUTOBACKUP
       MAXSEQ 5           # start at sequence 5 and count down (optional)
       MAXDAYS 5;         # start at UNTIL TIME and search back 5 days (optional)
       MOUNT DATABASE;
}

  5. Verify what is available for incomplete recovery.

    We will recover with the highest available redo information.  In a RAC database, both thread must be considered to determine highest available redo.  The options are "until time", "until scn", or "until sequence".  We will use the log sequence in this case.

   a.  First we need to find the highest sequence of each thread:

SQL> select max(sequence#) from v$archived_log L, v$database D

            where L.resetlogs_change# = D.resetlogs_change# and 

            thread#=1;

       MAX(SEQUENCE#)
       --------------
               25

SQL> select max(sequence#) from v$archived_log L, v$database D

            where L.resetlogs_change# = D.resetlogs_change# and 

            thread#=2;

       MAX(SEQUENCE#)
       --------------
             13

  b.  Next is to find the thread with lowest NEXT_CHANGE# scn.

SQL> select sequence#, thread#, first_change#, next_change#
             from v$archived_log L, v$database D
             where L.resetlogs_change# = D.resetlogs_change# and
             sequence# in (13,25);

      SEQUENCE#    THREAD# FIRST_CHANGE# NEXT_CHANGE#
     -------------------- -------------- ------------------------- -------------------------
                            25            1                           1744432                    1744802
                            13            2                           1744429                    1744805

SQL> select sequence#, thread#, first_change#, next_change#
           from v$backup_redolog
           where sequence# in (13,25);

      SEQUENCE#    THREAD# FIRST_CHANGE# NEXT_CHANGE#
      -------------------- -------------- ------------------------- -------------------------
                            25            1                           1744432                    1744802
                            13            2                           1744429                    1744805

In this case the next_change# SCN in thread 1 sequence 25 is lower than sequence 13 thread 2.  In a RAC environment, we use the lower to ensure we have the redo required from BOTH threads.   In other words, we use the lower (thread# 1) to ensure that ALL scn (s) in thread #1 exist in the available sequence for thread #2.

So we will set sequence 26 for thread 1 for RMAN  'until sequence'  recovery,  because RMAN stops the recovery  before applying the indicated sequence. Log sequence for  recovery  needs always  be sequence+1 to end  at +1 after applying the prior sequence.  I.e.:

       SET UNTIL SEQUENCE 26 THREAD 1;

6.  Get the command to add TEMPFILES after opening DB.

Locally Managed Temporary Tablespaces are not restored by  RESTORE command, we need to create them manually after recovery is complete.

If using LMT Temporary tablespace the controlfile will have the syntax  to add the tempfile after recovery is complete. The following command will give us the create controlfile statement:

               SQL> alter database backup controlfile to trace;

                Example:

      # Commands to add tempfiles to temporary tablespaces.
      # Online tempfiles have complete space information.
      # Other tempfiles may require adjustment.
        ALTER TABLESPACE TEMP ADD TEMPFILE '/dev/db/temp_01.dbf'  SIZE 41943040  REUSE AUTOEXTEND OFF;
      # End of tempfile additions.
      #

NOTE:  In newer versions, the tempfiles are added automatically. 

7. Run the rman script

Since log sequence 13 thread 2 next_change# is 3 changes ahead of thread 1 sequence 25 we are using sequence 26 (25+1) to stop recovery. This will restore  the data files and recover them applying all of sequence #25 of thread 1 and stopping at sequence #26. 

run {
       SET UNTIL SEQUENCE 26 THREAD 1;
       RESTORE DATABASE;
       RECOVER DATABASE;
       ALTER DATABASE OPEN RESETLOGS;
      }

 8. Review and understand the impact of resetlogs on the catalog.

After resetlogs a new incarnation for the database is recorded in the RMAN catalog and database controlfile.  Only one incarnation can be current and any need to restore from a previous incarnation requires you to "reset database to incarnation...". 

For example:

RMAN> LIST INCARNATION OF DATABASE V112;

List of Database Incarnations
DB Key  Inc Key  DB Name  DB ID            CUR  Reset SCN  Reset Time
-----------  ----------- ------------ ----------------  ------- --------------  ---------------
2656          2657       V112         228033884      NO   1                   29-MAY-13
2656          3132       V112         228033884      YES  1744806       13-JUN-13

We see that an "open resetlogs" was executed against this database on 13-JUN-2013. 

9. RMAN Sample Commands

* With a dedicated listener (not using instance registration)  restoring the controlfile.

 run {
 ALLOCATE CHANNEL D1 TYPE DISK CONNECT 'SYS/RAC@NODE1';
 ALLOCATE CHANNEL D2 TYPE DISK CONNECT 'SYS/RAC@NODE2';
  SET UNTIL SEQUENCE 14 THREAD 2;
   RESTORE CONTROLFILE;
  ALTER DATABASE MOUNT;
 RELEASE CHANNEL D1;
 RELEASE CHANNEL D2;
 }

 * Backup Archivelog

 BACKUP ARCHIVELOG ALL NOT BACKED UP 3 TIMES;
 BACKUP ARCHIVELOG UNTIL TIME 'SYSDATE-2' NOT BACKED UP 2 TIMES;