Setting the JVM heap size

You can pass parameters to the JVM to set the minimum and maximum heap sizes; the default maximum heap size is 256 MB. To give more capacity to a message flow that is going to process large messages, reduce the minimum JVM heap size to allow the main memory heap to occupy more address space.

Increase the maximum heap size only if you use Java intensively with, for example, user-defined nodes.

Use caution when you set the maximum heap size, because the Java Runtime Environment takes the values for its initial, maximum, and current heap sizes to calculate how frequently it drives garbage collection. A large maximum heap size drives garbage collection less frequently. If garbage collection is driven less frequently, the heap size associated with the integration server continues to grow.

Use the information on JVM parameter values on the mqsichangeproperties command to set the heap size that you require.