Oracle Database 12c: EM Express and CDB

Enterprise Manager Database Express, also referred to as EM Express, provides support for CDB.  Users can configure EM Express both at the root and the PDB containers, with each container using a different HTTPS/HTTP port.

At the root container, data is displayed for the entire CDB, and all actions taken impact all containers.  Data pertaining to a PDB, such as a user or a SQL statement, is qualified with the container name.  The actions a user can perform at the root container include: viewing and setting initialization parameters; administering common users and privileges; and managing memory configuration, undo information and redo logs.

When a user is connected to a PDB, data is displayed only for the container in question, and actions only impact that container.  This means that data pertaining to the CDB will not be visible at the PDB, and not all pages will be available.  The actions a user can perform when connected to a PDB include viewing and setting initialization parameters for the PDB, and managing tablespaces and profiles.

The functionality available on a CDB and a PDB is not identical, and also differs from the functionality available on a non-CDB system.

EM Express CDB Home Page

Active Report Examples

Performance Hub (Root)
Performance Hub (PDB)

Frequently Asked Questions


How do I configure EM Express on a CDB?

You can configure EM Express at the root container or at the PDB.  Simply login to the container and set the HTTPS/HTTP port.  Each container will need to use a different port.
SQL> connect sys/<password>@<container> as sysdba

SQL> exec dbms_xdb_config.sethttpsport(5501);

PL/SQL procedure completed

If you're using a listener TCP port other than 1521, you will also need to set the dispatchers and local_listener  initialization parameters, just like you would in a non-CDB system.  Please see the documentation for further information.

Why is the Storage menu missing the Tablespaces entry in a CDB?

Tablespaces are local to a PDB, so the Tablespaces entry is not available at the root container.  To view and manage tablespaces or datafiles on a PDB, go to the EM Express configured on that PDB.

Can I manage and create Common Users with EM Express?

Yes, Common Users can be created and managed from the root container.

At the PDB container, you can only create and manage local users.

Why are tabs missing from the Performance Hub?

At the PDB container, only the Activity and Monitored SQL tabs are visible because these are the only tabs that display PDB-specific data. 

At the root container, all tabs are available in the Performance Hub.

Can I see the activity breakdown by PDB?

Yes, at the root container, you can see the Average Active Sessions breakdown by container using the Home Page and the Performance Hub (Summary tab or Activity tab).

This data is taken from ASH, not metrics, so you might see a discrepancy when comparing average active sessions per container against a different breakdown.

Why do I see PDB$SEED when viewing Activity breakdown by PDB?

Although PDB$SEED is just a seed database, when queries are issued against CDB_* views, the server internally switches to all containers, including PDB$SEED, to retrieve data.  If there are frequent queries against CDB_* views, this could result in activity captured against PDB$SEED.


Can I plug and unplug PDBs with EM Express?

No, EM Express does not provide full CDB management capabilities in DB


How can I tell if I'm connected to the root container or to a PDB?

You can get this information from the Status region in the home page.  If you are at the root container, the type will show "CDB (# of PDBs)", and if you are at the PDB, the region will include the Container Name to which you're connected.

In addition, the blue panel at the top of the page will have an icon on the top left that indicates if the database is a CDB.  The database name will be displayed after the icon:

EM Express CDB menu
If you're connected to a PDB, the container name will be displayed after the database name:

EM Express PDB menu