SQL> SELECT SCN_TO_TIMESTAMP(ORA_ROWSCN) FROM emp;
SELECT SCN_TO_TIMESTAMP(ORA_ROWSCN) FROM dept
*
ERROR at line 1:
ORA-08181: specified number is not a valid system change number
ORA-06512: at "SYS.SCN_TO_TIMESTAMP", line 1
Cause:
If you provide a value into SCN_TO_TIMESTAMP which is not a System Change Number or if the SCN is tool old then you will get this error.
You can check the oldest available SCN number in database.
select min(SCN) min_scn from sys.smon_scn_time;
MIN_SCN
160715227536
SELECT SCN_TO_TIMESTAMP(160715227536) FROM dual;
SCN_TO_TIMESTAMP(160715227536)
2014-07-19 15:10:36,000000000
If we check older SCN than minimum SCN then we will get the error.
SELECT SCN_TO_TIMESTAMP(160715227535) FROM dual;
ORA-08181: specified number is not a valid system change number
ORA-06512: at "SYS.SCN_TO_TIMESTAMP", line 1