## 3.1.2  Memory Information from Logs and Traces
In case of critical memory issues you can often find more detailed information in logs and trace files.
- Try to identify memory-related errors in the alert trace files in the SAP HANA database explorer (accessible via the View trace and diagnostic files link). Search for the strings 'memory' , 'allocat' , or 'OOM' (caseinsensitive).
- Check if an out-of-memory (OOM) trace file was created (users of SAP HANA Studio may need to view some trace files at the operating system level - see SAP Note 2573851 OOM rtedump file missing in HANA Studio ).
- Investigate error messages seen on the application side that occurred at times of high memory usage. If the application is an SAP NetWeaver system, good starting points for analysis are System Log (SM21), ABAP Runtime Error (ST22), and Job Selection (SM37).
If help from SAP Customer Support is needed to perform an in-depth analysis, the following information is valuable and should be added to the ticket:
- Diagnosis information (full system info dump). To collect this information, see section Diagnosis Information .
- Performance trace provides detail information on the system behavior, including statement execution details. The trace output is written to a trace file perftrace.tpt, which must be sent to SAP Customer Support. Please note that the trace must be captured while the issue is present or while reproducing the issue. To enable this trace, see section Performance Trace under Additional Analysis Tools for Support.
If specific SAP HANA system components need deeper investigation, SAP Customer Support can ask you to raise the corresponding trace levels to INFO or DEBUG, rerun the query and then send the indexserver trace files to SAP Customer Support.
To do so choose Trace Configuration in the SAP HANA database explorer and launch the Database Trace wizard. The following illustration shows the example of enabling the join engine trace (join_eval). You can enter a search string and then select the component in the indexserver.ini file and change the System Trace Level to the appropriate value. Some trace components (such as debug trace details for join engine) can create many megabytes of trace information and may also require an increase of the values maxfiles and
maxfilesize in the [trace] section of the global.ini file (see also SAP Note 2629103 SQL Traces Stop Writing When it Exceeds the Maximum Filesize ).
Internal details about SQL statement execution can be collected by enabling the Executor Trace; this provides the highest level of detail and should only be activated for the short time of query execution. After capturing the trace details you can upload the trace file (extrace.py) to SAP Customer Support. This trace is enabled by activating a configuration parameter as described and illustrated here.
Open the Configuration of System Properties view, edit the parameter trace in the [pythontrace] section of the executor.ini file, and change its value to on . When you change the default value, you have the option to set
values at each specific layer. The trace parameter is off by default. Click Change Layer to turn the parameter on. You can then change the configuration value for a selected database and for a selected layer:
## Related Information
Diagnosis Information [page 293]
Performance Trace [page 289]
SAP Note 2629103
SAP Note 2573851