You can use the Undo Management Details page in Oracle Enterprise Manager Database Express (EM Express) to view the following information about your undo configuration:
Name and current size of the undo tablespace
Auto extensible tablespace setting (Yes or No)
Current undo retention period
Note:
In a multitenant container database (CDB), the EM Express undo management features are available only in the root, not in the pluggable databases (PDBs).
To view undo information: