CREATE OR REPLACE PROCEDURE BACKUP_AUDIT AS
  LTIME DATE;
BEGIN
  SELECT SYSDATE INTO LTIME FROM SYS.DUAL;

  INSERT INTO DBA_AUDIT_TRAIL_BAK 
   (SELECT OS_USERNAME, USERNAME, USERHOST, TERMINAL, TIMESTAMP,
    OWNER, OBJ_NAME, ACTION, ACTION_NAME, NEW_OWNER, NEW_NAME, 
    OBJ_PRIVILEGE, SYS_PRIVILEGE, ADMIN_OPTION, GRANTEE, 
    AUDIT_OPTION, SES_ACTIONS, LOGOFF_TIME, LOGOFF_LREAD, 
    LOGOFF_PREAD, LOGOFF_LWRITE, LOGOFF_DLOCK, COMMENT_TEXT, 
    SESSIONID, ENTRYID, STATEMENTID, RETURNCODE, PRIV_USED, 
    CLIENT_ID, SESSION_CPU 
    FROM SYS.DBA_AUDIT_TRAIL WHERE TIMESTAMP<LTIME);
  COMMIT;
  DELETE SYS.AUD$ WHERE TIMESTAMP#<LTIME;
  COMMIT;
END;
/