How to find who Truncated the Table

SQL> conn / as sysdba
Connected.

SQL> EXECUTE DBMS_LOGMNR.ADD_LOGFILE( LOGFILENAME =>’+DG1/mudhalvan/onlinelog/group_1.003.345746983′);

PL/SQL procedure successfully completed.

SQL> EXECUTE DBMS_LOGMNR.ADD_LOGFILE( LOGFILENAME =>’+DG1/mudhalvan/onlinelog/group_2.004.345746983′,OPTIONS =>DBMS_LOGMNR.ADDFILE);

PL/SQL procedure successfully completed.

SQL> EXECUTE DBMS_LOGMNR.ADD_LOGFILE( LOGFILENAME =>’+DG1/mudhalvan/onlinelog/group_3.005.345746985′,OPTIONS =>DBMS_LOGMNR.ADDFILE);

PL/SQL procedure successfully completed.

SQL> EXECUTE DBMS_LOGMNR.START_LOGMNR(OPTIONS => DBMS_LOGMNR.DICT_FROM_ONLINE_CATALOG);

PL/SQL procedure successfully completed.

SQL> set lines 100
SQL> column sql_redo format a45
SQL> column username format a20

SQL> select sql_redo, username, timestamp from v$logmnr_contents where upper(sql_redo) like ‘%TRUNCATE%’;

SQL_REDO                                      USERNAME     TIMESTAMP
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truncate table emp;                             Mudhalvan    01-JUL-13