ORA-19909: datafile string belon…

When a database
goes through multiple incarnations, some backups can become
orphaned. Orphaned backups are backups that are created during
incarnations of the database that are not ancestors of the current
incarnation.
•For example, database incarnation is 5 and SCN is 7000. A
DBPITR is done at SCN 7000 to SCN
6666 and then RESETLOGS is performed. Now in current
incarnation 6 the backup taken between 6666 and 7000 SCN became
orphaned.

•Orphaned backups are usable by RMAN in cases where you wish to
restore the database to a point in time not in the current
incarnation path.

 
ORA-19909:
datafile string belongs to an orphan incarnation
Cause: Either
the specified datafile was restored from a backup that was taken
during a period of time
that has already
been discarded by a resetlogs operation, or Oracle cannot identify
which database incarnation the file belongs to.
The alert log
contains more information.
 
Action: Restore
a backup of this file that belongs to either the current or a prior
incarnation of the database.
If you are using
RMAN to restore, RMAN
will automatically select a correct backup.