tell me any impact on live database if change this values
SQL> select sum(bytes/1024/1024) from dba_data_files where TABLESPACE_NAME='UNDOTBS2';
SUM(BYTES/1024/1024)
--------------------
4739
SQL> show parameter undo
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
undo_management string AUTO
undo_retention integer 10800
undo_suppress_errors boolean FALSE
undo_tablespace string UNDOTBS2
SQL>
SQL>
SQL>
after change
SQL>
SQL> ALTER SYSTEM SET UNDO_RETENTION = 21600;
System altered.
SQL>
SQL> show parameter undo
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
undo_management string AUTO
undo_retention integer 21600
undo_suppress_errors boolean FALSE
undo_tablespace string UNDOTBS2