ORA-01113: file 5 needs media recovery

SQL> ALTER TABLESPACE TEST_USER ONLINE;
ALTER TABLESPACE TEST_USER ONLINE
*
ERROR at line 1:
ORA-01113: file 5 needs media recovery
ORA-01110: data file 5: 'D:\APP\ORADATA\DBRMAN\TEST_USER01.DBF'


Elapsed: 00:00:00.10
SQL> RECOVER TABLESPACE TEST_USER;
ORA-00279: change 2227017 generated at 12/17/2014 12:21:31 needed for thread 1
ORA-00289: suggestion :
D:\APP\ORADATA\DBRMAN_ARCHIVE\ARC0000000002_0865847632.0001
ORA-00280: change 2227017 for thread 1 is in sequence #2


Specify log: {<RET>=suggested | filename | AUTO | CANCEL}

Log applied.
Media recovery complete.
SQL> ALTER TABLESPACE TEST_USER ONLINE;

Tablespace altered.

Elapsed: 00:00:00.46
SQL>