Increasing the maximum JVM heap size of the WebSphere Message Broker HTTP listener

Problem(Abstract)

The broker-wide listener process (biphttplistener) handles both inbound requests and outbound replies for the HTTPInput and HTTPReply nodes across an entire broker. By default, this listener is started with a maximum JVM heap size of 192MB.

It is possible, based on inbound request rates and message sizes, that the default maximum size is not sufficient.

Symptom

If the JVM heap of the HTTP listener attempts to grow beyond the maximum JVM heap size, Java OutOfMemory errors are reported through several files in the common/errors directory of your broker's workpath:
heapdump.date.time.pid.0001.phd
javacore.date.time.pid.0002.txt
Snap.date.time.pid.0003.trc

The stderr/console file of your HTTP listener will also include the error: "java.lang.OutOfMemoryError".
This can be found, here:
{MQSI_WORKPATH}/components/<broker>/httplistener/

Cause

When a JVM requests memory above its maximum size, Java garbage collection is called. If this does not free enough memory for the request, the JVM will crash, resulting in javacore, heapdump, and snap traces.

Resolving the problem

If you encounter these errors during testing, you can increase the maximum JVM heap size of the HTTP listener, to allow larger messages to be processed.
The maximum JVM heap size of the HTTP listener can be changed by issuing a command to the broker, specifying the new maximum JVM heap size in bytes.

For example, the following command sets the maximum JVM heap size of the biphttplistener to 512MB:
mqsiservice broker -r MaxJVMHeapSize=536870912

You will need to restart your broker after running this command.