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

Technote (troubleshooting)


The broker-wide listener process (biphttplistener) handles both inbound and outbound requests for the HTTPInput and HTTPReply nodes across an entire broker. This listener is started with a default maximum JVM heap size of 192MB. It is possible, based on input request rates and message size that the default maximum size is not sufficient.


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 WebSphere Message Broker workpath:

The stderr file of your HTTP listener also includes "java.lang.OutOfMemoryError".


When an internal JVM needs to grow beyond its maximum size, it crashes. This results 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 to 512MB:
mqsiservice broker -r MaxJVMHeapSize=536870912
Restart your broker after running this command.

Product Alias/Synonym

WMB MB WebSphere Message Broker MQ Integrator WBIMB WBI-MB MQSI WMQI

Document information

More support for:

WebSphere Message Broker

Software version:

6.1, 7.0, 8.0

Operating system(s):

AIX, HP-UX, Linux, Solaris, Windows, z/OS

Reference #:


Modified date:


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