Tales From A Lazy Fat DBA

Oracle Database 23ai introduces a new parameter, SESSION_EXIT_ON_PACKAGE_STATE_ERROR, designed to enhance session management and prevent potential data corruption by enforcing a hard session exit when the session state becomes invalidated.

Why SESSION_EXIT_ON_PACKAGE_STATE_ERROR Matters ?

In typical Oracle database environments, stateful PL/SQL packages, MLE modules, or environments may be modified while sessions actively use them. This can lead to errors such as:

• ORA-04068: Can occur when a PL/SQL package body is recompiled, invalidating the session state.
• ORA-4106 / ORA-4107: Can be raisrd when an MLE module or environment is altered via DDL, invalidating the session.

By default, the session remains active and throws an error when the invalid package or module is called. However, many applications may not properly handle these errors, leading to silent data corruption or unexpected behavior.

The SESSION_EXIT_ON_PACKAGE_STATE_ERROR parameter mitigates this risk by forcing an immediate session exit instead of raising an error.

Some of the benefits of using the parameter.

• Prevents Data Corruption: By terminating sessions with invalid state, the risk of silent data corruption is reduced.
• Simplifies Error Handling: Many applications are better at handling session disconnects than catching specific errors like ORA-04068.
• Consistency Across Sessions: Ensures that all sessions dealing with modified packages or MLE modules are treated consistently, minimizing inconsistencies.

How SESSION_EXIT_ON_PACKAGE_STATE_ERROR Works

When SESSION_EXIT_ON_PACKAGE_STATE_ERROR is set to TRUE, the following behavior is enforced:

1. PL/SQL Package Modification:
   • If a stateful PL/SQL package is modified, any active session that tries to invoke the package receives ORA-04068. With this parameter set to TRUE, the session exits immediately instead of raising the error.
2. MLE Module or Environment Modification:
   • If an MLE module or environment is modified via DDL, active sessions receive ORA-4106 or ORA-4107. With SESSION_EXIT_ON_PACKAGE_STATE_ERROR = TRUE, these sessions are forcibly disconnected.
3. Application Handling:
   • Most applications are designed to capture session disconnects and reestablish connections, streamlining recovery from session invalidation.

Use Cases

• High-Availability Environments: In systems where continuous uptime is critical, preventing data corruption is paramount.
• Distributed Applications: Applications spread across multiple environments that frequently modify PL/SQL packages or MLE modules benefit from session termination to maintain data integrity.
• Oracle RAC Deployments: Different instances in an Oracle RAC environment can independently configure this parameter, allowing fine-grained control based on workload requirements.

Configuring SESSION_EXIT_ON_PACKAGE_STATE_ERROR:

Examples:
ALTER SYSTEM SET SESSION_EXIT_ON_PACKAGE_STATE_ERROR = TRUE;
ALTER SESSION SET SESSION_EXIT_ON_PACKAGE_STATE_ERROR = TRUE;
ALTER SYSTEM SET SESSION_EXIT_ON_PACKAGE_STATE_ERROR = TRUE SCOPE = SPFILE;

Considerations

• Default Behavior: By default, this parameter is set to FALSE, meaning sessions will raise errors rather than exit.
• Testing and Validation: Test this configuration in lower environments to ensure application compatibility.
• Session Management: Monitor session disconnects to ensure that forced exits do not disrupt critical workflows.

Conclusion

SESSION_EXIT_ON_PACKAGE_STATE_ERROR is a powerful new feature in Oracle Database 23ai that enhances session management by enforcing session termination on package or module state invalidation. By using this parameter, Oracle environments can significantly reduce the risk of data corruption and streamline error handling processes across diverse applications. Whether managing PL/SQL packages or MLE modules, this parameter offers greater control and reliability for database administrators and developers both.

Hope It Helped!
Prashant Dixit