Introduction

 

You might be familiar with the DB Control, which was available with 10g and 11g databases. In 12c, this is replaced by a light weight tool called Enterprise Manager Database Express (EM Express). EM Express is the web-based interface for managing the 12c database, including the multitenant databases. It can handle the common core of tasks done by DBAs such as managing users, managing database initialization parameters, memory or storage, checking performance and SQL Tuning Advisor information etc.

The main advantage of EM Express is that it does not have its own repository or background tasks or processes that periodically collect information, thereby reducing the load on the database server. At the same time, it can handle the basic administrative tasks performed by DBAs. The remaining functions done by the DB Control in11g can still be done by using the Enterprise Manager DB Plug-in deployed from Enterprise Manager Cloud Control 12c.

How to configure EM Express

 

How does EM Express handle these tasks if there is no repository or background processes? It is a browser-based UI that does its job by sending requests to the Database Listener, which invokes a servlet which runs SQL and returns HTML to the browser. Hence, the configuration is also simple, requiring only a port to be enabled in the DB listener. There is no separate installation required for EM Express.


1. Ensure the listener is up and running


$ lsnrctl status

 

2. If the listener is not running on the default port 1521, ensure to set the local_listener parameter.

 

ALTER SYSTEM SET LOCAL_LISTENER=listener1;

 

Resolve the listener name alias for the LOCAL_LISTENER setting through a tnsnames.ora file on the database host using a text editor, as follows:

 

listener1=

(DESCRIPTION =

(ADDRESS = (PROTOCOL=tcp)(HOST=db-server)(PORT=1525)))


3. Enable the TCP dispatcher


dispatchers="(PROTOCOL=TCP)(SERVICE=<sid>XDB)"


 

4. Ensure the ORCL12cXDB service is registered in the listener.

 

5. Now, we can configure the port in the database. To access EM Express, the database should be open. If the database is created by DBCA, the port may be configured already. We can verify this using dbms_xdb.getHttpPort() , for HTTP port or dbms_xdb.getHttpsPort(), for HTTPS port.

 

For example:

disp.png

 

If its not configured or if you want to change it, you can do so. The port can be set using dbms_xdb.setHttpPort()for HTTP port or dbms_xdb.setHttpsPort() for HTTPS port.

 

Please note we can use either HTTP port or HTTPS port to connect to the database. Both need not be configured.

disp.png

 

6. To access EM Express, enter a URL in the following format in a Web browser, specifying the EM Express port number:

 

https://database-hostname:portnumber/em/

 

Use the following query while connected to the database to generate the URL :

 

For HTTPS :

 

(a) If DB_DOMAIN is configured

SELECT 'https://'||SYS_CONTEXT('USERENV','SERVER_HOST')||'.'||SYS_CONTEXT('USERENV','DB_DOMAIN')||':'||dbms_xdb_config.gethttpsport()||'/em/' from dual;

 

(b) If DB_DOMAIN is not configured

 

SELECT 'https://'||SYS_CONTEXT('USERENV','SERVER_HOST')||':'||dbms_xdb_config.gethttpsport()||'/em/' from dual;

 

For HTTP :

 

(a) If DB_DOMAIN is configured

 

SELECT 'http://'||SYS_CONTEXT('USERENV','SERVER_HOST')||'.'||SYS_CONTEXT('USERENV','DB_DOMAIN')||':'||dbms_xdb_config.gethttpport()||'/em/' from dual;

 

(b) If DB_DOMAIN is not configured

 

SELECT 'http://'||SYS_CONTEXT('USERENV','SERVER_HOST')||':'||dbms_xdb_config.gethttpport()||'/em/' from dual;

 

disp.png

 

Use this URL in any browser to access the EM Express

 

7. The privileges required to access EM Express:

 

By default SYS and SYSTEM users have the required privileges to access EM Express. For other users, you can grant:

 

EM_EXPRESS_BASIC: enables users to connect to EM Express and to view the pages in read-only mode.

EM_EXPRESS_ALL    : enables users to connect to EM Express and use all the functionality provided by EM Express (read/write access to all EM Express features).


Note: EM Express can be configured in RAC , CDB or PDB databases.

 

Note: You can configure EM Express in the CDB level and even for separate PDBs.

What are the functionalities available with EM Express

 

Dashboard

 

Dashboard gives an overview on what is going on in the database.

It contains various sections such as the Status, Incidents reported in last 24 hours, Jobs currently running in the database, Performance, Resource Usage, SQL Monitor information. Option to further drill down is limited.


  • Status: This section contains and overview of the main characteristics of the database, such as Version, Database Name, Oracle Home, Last Backup, and so on.
  • Performance: In this pane, you find a simplified breakdown of resource consumption.
  • Incidents: This section lists the problems have been detected and stored in the Automatic Diagnostic Repository.
  • Resources: This pane gives you an overview of the database/server resource consumption in terms of CPU, memory, or storage.
  • Running Jobs:  This section lists the Database Scheduler Jobs currently being executed.
  • SQL Monitor: This pane shows the SQL Monitor information. The statement IDs are active links that you can click to access the SQL Monitor tool.

 

The other main tabs include Configuration, Storage, Security and Performance.

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Configuration tab contains sections such as Initialization parameters, Memory, Database Feature Usage and the Current database properties.

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Storage tab contains drop down to access details of the tablespaces, Undo & Redo management and Control file management.


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Details on Users, roles and profiles are present under the Security tab.

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The Diagnostic Pack and Tuning Pack licenses required for accessing Performance hub and SQL Tuning Advisor respectively, are found under the Performance tab.

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.

Conclusion

 

EM Express is not a replacement of DB Console. It is a light weight yet powerful GUI tool which helps the Database Administrators in the basic day to day activities. For further options, you will have to use the Cloud control portal