JVM parameter values

To change these properties, you must specify the broker name, and set the ObjectName to ComIbmJVMManager. If you are setting a debug port number, you must also include -e and specify the name of the integration server which will use the port.

-n jvmMinHeapSize

The minimum size of the storage available to the JVM, specified in bytes.

• Value type: integer
• Initial value: -1, which represents 33554432 bytes (32MB) with the global cache disabled, or 100663296 (96MB) with the global cache enabled

-n jvmMaxHeapSize

The maximum size of the storage available to the JVM, specified in bytes. If you have configured a publish/subscribe domain, when integration servers retain publications, you might need to increase this value. If you have included the XSLTransform node in one or more message flows, and the node is processing very large XML messages, you might also have to change this parameter.

• Value type: integer
• Initial value: -1, which represents 268435456 bytes (256 MB)

-n jvmDebugPort

The port on which the integration server is listening. You must set a port number to activate debug in the integration server.

• Value type: integer
• Initial value: 0

Warning: When the jvmDebugPort is enabled, a remote user can connect to the broker's JVM and inspect its behavior and data, including potentially sensitive information. A remote user can also exert control over the broker's behavior. It is therefore recommended that the jvmDebugPort is disabled on production systems.

-n jvmNativeStackSize

The maximum stack size for Java threads.

• Value type: integer
• Initial value: -1, which represents 1048576 bytes (1 MB) on Solaris and Linux platforms, otherwise the value is JVM dependent

-n jvmJavaOSStackSize

The default stack size for Java Operating System threads. If you have a message flow with large number of nodes between two nodes written in Java (for example, JavaCompute nodes or Java user-defined nodes), you might have to increase the size of this parameter.

• Value type: integer
• Initial value: JVM dependent

-n jvmSystemProperty

The value of this property defines Java system properties for an integration server that can be used by JavaCompute nodes. The format is in the form -Dname1=value1. You can also set non-standard -X parameters to the JVM on the same list, depending on your operating system. You can set multiple properties in the following way:

-v"-Dname1=value1 -Dname2=value2"

Note: As shown in this example, there must not be a space character after the -v parameter.

• Value type: integer
• Initial value: JVM dependent

-n jvmVerboseOption

The value of this property identifies the type of Java verbose information that is displayed for an integration server.

• Value type: string
• Initial value: none
• Other valid values:
  • class: display information about each class loaded
  • jni: display information about use of native methods and other Java Native Interface activity
  • gc: display information about each garbage collection event
  • all: display information for all of the verbose options

See the mqsichangeproperties command for examples of how to change parameters for the JVM. Other examples are provided for particular tasks:

• Using the Test Client in trace and debug mode
• Attaching the flow debugger to an integration server for debugging
• Setting the JVM heap size