Resolving ORA-00019: Maximum Number of Session Licenses Exceeded in Oracle Database

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To resolve ORA-00019 Maximum Number of Session Licenses Exceeded

Encountering the “ORA-00019: maximum number of session licenses exceeded” error in Oracle Database can be challenging sometimes for database administrators.

This error indicates that the maximum number of concurrent sessions allowed for the Oracle instance has been exceeded. In this post, we will explore effective ways or solutions to resolve the ORA-00019 error.

Description:

The ORA-00019 error is a result of reaching the configured limit on the number of concurrent sessions that can be active at the same time in the Oracle Database instance. When this limit is exceeded, new connection requests are denied, and the error is raised.

Common Causes: (ORA-00019: maximum number of session licenses exceeded)

The most common cause of this error is reaching the licensed limit for concurrent sessions. Oracle Database has a licensing model that restricts the number of simultaneous connections based on the purchased license.

Improper Configuration:

Incorrect configuration settings relate to the maximum number of sessions allowed. This may happen when the configured limit is set too low for the actual workload.

Solution of ORA-00019: maximum number of session licenses exceeded

Resolving the ORA-00019 error involves altering the configuration settings and ensuring compliance with the licensing terms. Here are the steps to address this issue:.

  1. Identify the current sessions:
    Use the following SQL query to identify the current active sessions:

SQL> SELECT COUNT(*) FROM V$SESSION;

  1. Review Licensing Terms:
    Ensure that the number of active sessions does not exceed the licensed limit for your Oracle Database instance. Check the licensing terms or consult with the organization’s license administrator.
  1. Alter or adjust configuration parameters:
    Modify the Oracle Database initialization parameters related to the maximum number of concurrent sessions. The relevant parameters are sessions and processes.

SQL> ALTER SYSTEM SET SESSIONS = SCOPE=SPFILE;
SQL> ALTER SYSTEM SET PROCESSES = SCOPE=SPFILE;

Replace with the desired limit for concurrent sessions.

  1. Restart the database.
    After modifying the initialization parameters, restart the Oracle database for the changes to take effect.
    SQL> SHUTDOWN IMMEDIATE;

SQL> STARTUP;

Example:
Assuming that the current number of sessions is 150 and the licensed limit is 200, you can adjust the configuration as follows:

To identify current sessions
SQL> SELECT COUNT(*) FROM V$SESSION;

To adjust configuration parameters
SQL> ALTER SYSTEM SET SESSIONS = 200 SCOPE=SPFILE;
SQL> ALTER SYSTEM SET PROCESSES = 250 SCOPE=SPFILE;

To Restart the database
SQL> SHUTDOWN IMMEDIATE;
SQL> STARTUP;

Conclusion:

Resolving the ORA-00019 error involves a careful review of licensing terms and the adjustment of Oracle Database configuration parameters. By ensuring compliance with licensing and appropriately configuring the maximum number of sessions, administrators can mitigate the impact of this error and maintain a stable database environment. Regular monitoring and proactive management of database resources are essential to prevent the recurrence of such issues.

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