## 3.2.3  Resolving CPU Related Issues
The first priority in resolving CPU related issues is to return the system to a normal operating state, which may complicate identifying the root cause.
## Immediate Remedial Action
Issue resolution should aim to bring the system back to a functional state by stopping the operation that causes the high CPU consumption. However, after resolving the situation it might not be possible to find out the actual root cause, you should therefore consider recording a HANA Runtime Dump before taking any countermeasures. See SAP Note 1813020 How to generate a runtime dump on SAP HANA and Analysis of CPU Related Issues .
You can identify and stop the specific operation causing high CPU consumption using the Threads Monitor in SAP HANA Cockpit (see Thread Monitoring). Use the values in the columns Client Host, Client IP, Client PID and Application User to identify the user that triggered the operation. Contact the user to confirm what actions are currently being performed and agree on how to resolve the situation; two options are available:
- On the client side, end the process calling the affected threads
- Cancel the operation by selecting the thread in the Threads Monitor and choose Cancel Operation.
For further analysis of the root cause, you may need to open a ticket to SAP HANA Development Support and attach the Full System Info Dump.
## Analysis of the System Configuration
Under normal circumstances when the SAP HANA Database instance is correctly configured, exhaustion of CPU resources should not occur. Firstly, therefore, verify that the configuration conforms to SAP recommendations using the script HANA_Configuration_Parameters_2.00.040+ in the SQL Statement Collection for SAP HANA (attached to SAP Note 1969700). The output of this script will list all parameters deviating from recommended settings. In this situation pay particular attention to the workload management related parameters such as default_statement_concurrency_limit as outlined in section 'Controlling Parallel Execution of SQL Statements'.
## Scenario Illustrating Unusual Load Peaks
Even if the workload management related parameters are set as recommended, CPU resources may still be exhausted by unusual peaks in the workload. Considering the following scenario:
- A system is configured with 144 CPU cores
- The default_statement_concurrency_limit is set to 48 - therefore an application workload may consume 33.3% of the available CPU resources
- An application submits an OLAP workload request to the HANA database (with a higher degree of parallelism) which, within the foreseen workload management boundaries, requires 33% of the available resources.
If, however, the application submits 3 such requests via 3 different sessions simultaneously this workload may easily exhaust the CPU resources. This illustrates the importance of finding the right workload management balance for your individual system; there is no "one-configuration-fits-all' approach and you may therefore need to change the workload management related configuration parameters to fit your own specific application requirements. In the given scenario, for example, the solution may be to further decrease the concurrency degree of individual database requests by adjusting default_statement_concurrency_limit to even lower levels.
## Related Information
Analysis of CPU Related Issues [page 83]
Thread Monitoring
Controlling Parallel Execution of SQL Statements [page 87]
SAP Note 1969700 - SAP HANA Statement Collection
SAP Note 1813020 - How to generate a runtime dump on SAP HANA