Troubleshooting memory issues for BPM servers

IBM BPM, V8.0.1, All platforms > Troubleshooting and support
Troubleshooting memory issues for BPM servers

If you are using IBM BPM with a 32-bit operating system or Java Virtual Machine (JVM), you might notice issues with server performance and availability, including OutOfMemory exceptions. These happen when the operating system or JVM does not have enough accessible memory to support all the running processes.

If the server performance is severely degraded or if you see an OutOfMemory exception, consider switching to a 64-bit operating system or JVM. Otherwise, use the information in the following table to identify possible solutions for specific memory issues.

Observable memory issues and suggested actions
Observed behavior Possible actions
Severely degraded server performance (swapping occurs)

Ensure there is enough physical memory to support IBM BPM and all other running processes. Use the system memory analysis tool for your platform (for example, vmstat for Linix or UNIX platforms, or Task Manager for Windows platforms).
If that some 32-bit operating systems can only use a specific amount of physical memory.

Stop any running processes that are not critical to BPM (for example, extra browser windows or other installed applications).

Establish a remote DB2 connection and use it instead of the local DB2 instance. Stop all local DB2 processes on the local machine.

If you are authoring processes, use a remote unit test environment and Process Center instead of running them on your local machine.

Severely degraded server performance (no swapping) combined with excessive garbage collection activity

Increase the maximum Java heap size. The heap size needs to be large enough to contain all of the required Java objects, but small enough to prevent bottlenecks from large amounts of native memory.

Tune the JVM heap.

For more information on tuning the heap size and garbage collection settings, see Tuning the IBM virtual machine for Java and Java virtual machine settings at the end of this topic.
An OutOfMemory exception

If the exception is immediately preceded by frequent garbage collection activity that does not free space in the Java heap, use the information in the previous row to increase the maximum Java heap size, tune the JVM heap, or both.

If the exception is not immediately preceded by garbage collection activity, it can indicate that the native memory for a resource has been exhausted. Decrease the maximum Java heap size to allow more room for native memory in the JVM address space.

If the exception occurs when you try to download Process Designer from the Process Center Console...

Exit the Process Center Console.
Use the WebSphere administrative console to set a custom property for the web container:

Click Servers > Server Types > WebSphere application servers > serverName > Web container > Custom properties.
Add the com.ibm.ws.webcontainer.channelwritetype property and set its value to synch.
Save your changes and exit the administrative console.

Restart the Process Center Console and resume downloading Process Designer.

Memory issues; for example, the instance occupies much of the available memory
Reduce the branch context cache size. Reducing the cache size from 64 to 16 makes a huge difference in the amount of memory the instance uses, although you are trading off some performance for the improvement in memory use.
To change the cache size, locate the 00static.xml file in PROFILE_HOME\config\cells\cell_name\nodes\node_name\servers\server_name\process-server\config\system. In it, you can edit the value for branch-context-max-cache-size.

Troubleshooting and support for IBM BPM

Related information:

Technote: How to resolve memory issues for IBM BPM V7.5 servers

Observed behavior	Possible actions
Severely degraded server performance (swapping occurs)	Ensure there is enough physical memory to support IBM BPM and all other running processes. Use the system memory analysis tool for your platform (for example, vmstat for Linix or UNIX platforms, or Task Manager for Windows platforms). If that some 32-bit operating systems can only use a specific amount of physical memory. Stop any running processes that are not critical to BPM (for example, extra browser windows or other installed applications). Establish a remote DB2 connection and use it instead of the local DB2 instance. Stop all local DB2 processes on the local machine. If you are authoring processes, use a remote unit test environment and Process Center instead of running them on your local machine.
Severely degraded server performance (no swapping) combined with excessive garbage collection activity	Increase the maximum Java heap size. The heap size needs to be large enough to contain all of the required Java objects, but small enough to prevent bottlenecks from large amounts of native memory. Tune the JVM heap. For more information on tuning the heap size and garbage collection settings, see Tuning the IBM virtual machine for Java and Java virtual machine settings at the end of this topic.
An OutOfMemory exception	If the exception is immediately preceded by frequent garbage collection activity that does not free space in the Java heap, use the information in the previous row to increase the maximum Java heap size, tune the JVM heap, or both. If the exception is not immediately preceded by garbage collection activity, it can indicate that the native memory for a resource has been exhausted. Decrease the maximum Java heap size to allow more room for native memory in the JVM address space. If the exception occurs when you try to download Process Designer from the Process Center Console... Exit the Process Center Console. Use the WebSphere administrative console to set a custom property for the web container: Click Servers > Server Types > WebSphere application servers > serverName > Web container > Custom properties. Add the com.ibm.ws.webcontainer.channelwritetype property and set its value to synch. Save your changes and exit the administrative console. Restart the Process Center Console and resume downloading Process Designer.
Memory issues; for example, the instance occupies much of the available memory	Reduce the branch context cache size. Reducing the cache size from 64 to 16 makes a huge difference in the amount of memory the instance uses, although you are trading off some performance for the improvement in memory use. To change the cache size, locate the 00static.xml file in PROFILE_HOME\config\cells\cell_name\nodes\node_name\servers\server_name\process-server\config\system. In it, you can edit the value for branch-context-max-cache-size.