Getting UNDO_RETENTION best possible value quickly

With this simple query below we can check what is the recommended value of undo_retention parameter:


SYS@EXADB08 AS SYSDBA> SELECT dbms_undo_adv.best_possible_retention(SYSDATE-1/24, SYSDATE)
FROM dual;  2 

DBMS_UNDO_ADV.BEST_POSSIBLE_RETENTION(SYSDATE-1/24,SYSDATE)
-----------------------------------------------------------
                            1575436

Elapsed: 00:00:00.03
SYS@EXADB08 AS SYSDBA>



Best Regards,
Paulo Portugal