SAP Note 21762 - Duplicate entries in control file / V$DATAFILE

Symptom:

Duplicate entries in the control file and in the display via view
V$DATAFILE.
The filename in the second, doubled entry, is empty.

Cause and prerequisites

Incorrect display! This is caused when the internal ORACLE file number is used again, e.g.
- During reorganization of a tablespace (drop/create tablespace ...)
- When moving data files to another file system
(alter database rename file '...' to '...';)

Solution
The error can be ignored (repaired in ORACLE Rel. 7.3)