Ora-02393 Exceeded Call Limit On CPU Usage

In the world of database management systems, encountering performance issues is an inevitable challenge. One such problem that can arise is the Ora-02393 Exceeded Call Limit on CPU Usage. This error occurs when a specific session exceeds the limit set for its CPU usage. It can be a frustrating issue to deal with, but understanding its causes and potential solutions can help in resolving it effectively.

Understanding the background of Ora-02393 is crucial in troubleshooting the issue. This error is commonly experienced in Oracle databases and is typically a result of poorly optimized SQL queries or inefficient code execution. Exceeding the CPU usage limit can lead to degraded performance and affect the overall system responsiveness. By analyzing the SQL statements causing the overload and optimizing them, database administrators can resolve this issue and improve the system's performance.

Understanding 'Ora-02393 Exceeded Call Limit on CPU Usage'

The error message 'Ora-02393 Exceeded Call Limit on CPU Usage' is encountered in Oracle databases when a session exceeds the specified CPU call limit. This limit is set to prevent excessive CPU usage and ensure fair resource distribution among multiple sessions. When a session exceeds its CPU call limit, it is terminated to prevent monopolizing CPU resources and impacting the performance of other sessions.

Causes of 'Ora-02393 Exceeded Call Limit on CPU Usage'

The 'Ora-02393 Exceeded Call Limit on CPU Usage' error can occur due to various reasons. Let's explore some common causes:

• Complex queries: If a session executes a complex query that requires significant CPU resources, it can exceed the call limit and trigger the error.
• Improper resource management: If the Oracle database has not been properly configured to limit the CPU usage per session, it can lead to sessions exceeding the call limit.
• High concurrency: When multiple sessions are executing resource-intensive operations simultaneously, the cumulative CPU usage can exceed the limit.
• Improper indexing: Inefficient indexing strategies can result in query execution plans that require excessive CPU resources, leading to the error.

Preventing 'Ora-02393 Exceeded Call Limit on CPU Usage'

To prevent the 'Ora-02393 Exceeded Call Limit on CPU Usage' error, consider implementing the following best practices:

• Optimize queries: Ensure that queries are properly optimized by using appropriate indexing strategies, reducing unnecessary CPU consumption.
• Review resource allocation: Continuously monitor and analyze the resource allocation for each session, adjusting the CPU limits as needed.
• Implement resource limits: Set appropriate CPU call limits for each session to prevent excessive resource consumption.
• Tune parallel processing: Adjust the parallel processing settings to balance the workload and prevent overloading of CPU resources.
• Monitor system performance: Utilize performance monitoring tools to identify sessions that are close to or exceeding the CPU call limit, allowing proactive measures to be taken.

Resolving 'Ora-02393 Exceeded Call Limit on CPU Usage'

If you encounter the 'Ora-02393 Exceeded Call Limit on CPU Usage' error, there are several steps you can take to resolve it:

• Analyze the query: Investigate the query that triggered the error and optimize it to reduce CPU usage.
• Review indexing: Check if the query execution plan could be improved with better indexing strategies.
• Adjust resource limits: Increase the CPU call limit for the specific session if it frequently exceeds the limit but does not impact system performance.
• Optimize system configuration: Ensure that the Oracle database is properly configured with appropriate resource management settings.
• Review hardware resources: Evaluate the hardware resources available and make necessary upgrades to meet the demands of the workload.

Understanding the Impact of 'Ora-02393 Exceeded Call Limit on CPU Usage'

'Ora-02393 Exceeded Call Limit on CPU Usage' can significantly impact the performance and stability of an Oracle database. When a session exceeds its CPU call limit, it is terminated, causing disruption to ongoing operations. This can result in delays, failed transactions, and reduced overall system efficiency.

Effects on System Performance

The primary impact of 'Ora-02393 Exceeded Call Limit on CPU Usage' is the degradation of system performance. When a session is terminated due to exceeding the CPU call limit, it can cause delays in ongoing transactions and disrupt other sessions that rely on the affected session's resources.

Transaction Rollbacks

When a session is terminated, any active transactions associated with that session will be rolled back. This rollback can be time-consuming, especially for transactions that have made significant changes to the database. It can lead to further delays and impact the overall system throughput.

Resource Contention

When the CPU call limit is exceeded, it can create resource contention within the database server. Other sessions may be waiting for resources that are being utilized by the terminated session, leading to increased latency and reduced overall throughput.

System Instability

If 'Ora-02393 Exceeded Call Limit on CPU Usage' errors occur frequently and impact multiple sessions, it can lead to system instability. The constant termination of sessions can generate a negative user experience, cause data inconsistencies, and require frequent system restarts to restore normal operations.

Managing CPU Usage in Oracle Databases

To effectively manage CPU usage in Oracle databases and avoid excessive resource consumption, it is essential to implement proper resource allocation and monitoring practices.

Setting CPU Call Limits

Setting appropriate CPU call limits for each session is vital to prevent excessive CPU usage. By allocating a fair share of CPU resources to each session, the impact of resource-intensive operations can be controlled, ensuring optimal system performance.

Considering the Workload

When determining the CPU call limits, it is essential to consider the workload of each session and the overall system capacity. Sessions performing complex operations may require higher CPU limits, while lower limits can be set for less critical operations.

Monitoring and Adjusting Limits

Regularly monitor the CPU usage for each session and adjust the call limits accordingly. If a session frequently exceeds its limit, it may be necessary to increase the limit to prevent premature termination. On the other hand, if a session consistently consumes minimal CPU resources, its limit can be reduced to distribute resources more efficiently.

Performance Monitoring Tools

To effectively manage CPU usage, utilize performance monitoring tools provided by Oracle, such as Oracle Enterprise Manager (OEM) and Oracle SQL Developer. These tools offer insights into the CPU utilization of individual sessions, allowing administrators to identify potential resource-intensive queries and take proactive measures to avoid performance issues.

Database Tuning

Database tuning plays a crucial role in optimizing CPU usage. By analyzing and fine-tuning the database configuration, including query optimization, indexing strategies, and parallel processing settings, administrators can minimize unnecessary CPU consumption and maximize overall system efficiency.

Effectively managing CPU usage in Oracle databases requires a holistic approach that includes proper resource allocation, monitoring, and database tuning. By implementing these best practices, organizations can ensure optimal performance and stability, while avoiding the 'Ora-02393 Exceeded Call Limit on CPU Usage' error.

Understanding Ora-02393 Exceeded Call Limit on CPU Usage

In Oracle database systems, the error message "Ora-02393 Exceeded Call Limit on CPU Usage" indicates that a particular process has exceeded the time limit set for CPU usage. This error is raised when a process consumes more CPU time than allowed by the system administrator or database configuration.

When this error occurs, it is important to investigate the underlying cause. The possible reasons for this error include poorly optimized queries, resource-intensive operations, or high concurrency on the database server.

To resolve this issue, the following steps can be taken:

• Identify the specific process or query causing the excessive CPU usage.
• Optimize the query or process to reduce CPU consumption.
• Check for any inefficient SQL statements and rewrite them if necessary.
• Consider implementing resource management techniques, such as setting CPU limits at the user or session level.
• Monitor the system to ensure that the CPU usage remains within acceptable limits.

By addressing the root cause and optimizing the database configuration, the Ora-02393 error can be resolved, resulting in improved performance and stability of the Oracle database system.

### Key Takeaways

Frequently Asked Questions

In this section, we will address frequently asked questions related to the "Ora-02393 Exceeded Call Limit on CPU Usage" error.

1. What does the "Ora-02393 Exceeded Call Limit on CPU Usage" error mean?

The "Ora-02393 Exceeded Call Limit on CPU Usage" error is encountered when the CPU usage for a particular call exceeds the allowable limit set in the Oracle database. This error occurs when a single SQL or PL/SQL statement consumes excessive CPU resources, leading to performance degradation and potential system instability.

To prevent excessive CPU consumption, Oracle provides a mechanism to limit the CPU time used by a single execution call. When the limit is surpassed, the "Ora-02393 Exceeded Call Limit on CPU Usage" error is raised to alert the user.

2. How can I diagnose the cause of the "Ora-02393 Exceeded Call Limit on CPU Usage" error?

Diagnosing the cause of the "Ora-02393 Exceeded Call Limit on CPU Usage" error involves analyzing the SQL or PL/SQL statement that is consuming excessive CPU resources. You can use the Oracle Enterprise Manager or database performance tuning tools to identify the problematic query or code block.

Additionally, reviewing the execution plan, identifying any resource-intensive operations, and optimizing the query or code can help resolve the issue. Monitoring CPU usage, system performance, and database workload can also provide valuable insights into the root cause of the error.

3. How can I mitigate the "Ora-02393 Exceeded Call Limit on CPU Usage" error?

To mitigate the "Ora-02393 Exceeded Call Limit on CPU Usage" error, you can take the following steps:

1. Analyze and optimize the SQL or PL/SQL statement causing the excessive CPU usage.

2. Consider alternative approaches such as rewriting the query, adding indexes, or optimizing the code logic.

3. Implement resource management techniques such as setting resource limits, utilizing resource profiles, or implementing database resource plans.

4. Monitor and analyze the system performance regularly, checking for any abnormal spikes in CPU usage.

By following these steps, you can effectively reduce the occurrence of the "Ora-02393 Exceeded Call Limit on CPU Usage" error and improve overall database performance.

4. Can I increase the call limit to prevent the "Ora-02393 Exceeded Call Limit on CPU Usage" error?

Yes, you can increase the call limit to mitigate the "Ora-02393 Exceeded Call Limit on CPU Usage" error. However, it is essential to carefully evaluate the impact on system resources and consider the potential consequences of raising the limit.

Increasing the call limit may temporarily provide relief but could lead to prolonged CPU usage and performance issues. It is recommended to address the root cause of excessive CPU consumption rather than rely solely on increasing the limit.

5. How can I monitor CPU usage and prevent the "Ora-02393 Exceeded Call Limit on CPU Usage" error?

Monitoring CPU usage is crucial to prevent the "Ora-02393 Exceeded Call Limit on CPU Usage" error. Here are a few steps you can take:

1. Set up database monitoring tools to track CPU usage in real-time.

2. Regularly review performance statistics and identify any sudden or sustained spikes in CPU utilization.

3. Optimize resource-intensive queries and code to minimize CPU consumption.

4. Implement proper resource management techniques like resource profiles and resource plans.

By actively monitoring CPU usage and taking proactive measures, you can ensure that the "Ora-02393 Exceeded Call Limit on CPU Usage" error is kept at bay, and your Oracle database performs optimally.

To sum it up, the Ora-02393 error occurs when the call limit on CPU usage is exceeded. This can happen when a process or query consumes too much CPU time, which can affect the performance of the entire database. It is important to address this issue promptly to prevent further disruptions and ensure optimal database performance.

To resolve the Ora-02393 error, there are several steps you can take. First, analyze the offending query or process to identify any inefficiencies or bottlenecks. Optimizing the code or enhancing the query execution plan can help reduce CPU usage. Additionally, you can consider implementing resource controls and limits to prevent one process from monopolizing the CPU. Regular monitoring and performance tuning are crucial to managing CPU usage and preventing the recurrence of the Ora-02393 error.