Setting the maximum rate for a message flow

The system administrator is able to restrict the rate that an individual message flow can run at by setting the maximum rate property. The maximum rate is specified as the total number of input messages processed every second. The maximum rate value is divided equally among all threads that are running in the message flow irrespective of the number of input nodes within the flow.

To calculate the number of threads within a specific message flow:

1. Count the number of input nodes within the flow.
2. Add on the number of additional instances that are specified for each input node.

The following three examples assume the maximum rate is set to 50, and helps to highlight some of the variations that can occur from basic to more complex scenarios:

• A message flow has one input node with no additional instances:
  • Only a single thread in operation.
  • The full maximum rate allocation of 50 messages every second is applied to that one thread.
• A message flow has one input node with one additional instance:
  • Two threads in operation. One for the node and one for the additional instance.
  • The maximum rate is split equally across the two threads. Each thread has a maximum rate allocation of 25 messages every second.
• A message flow has three input nodes with four additional instances that are specified on the first node and three additional instances that are specified on the second node:
  • 10 threads in operation. Three input node threads, four additional instance threads for the first node, and three additional instance threads for the second node.
  • The maximum rate is split equally across the 10 threads. Each thread has a maximum rate allocation of five messages every second.

If any individual thread exceeds their maximum rate allocation, a processing delay is introduced on that thread to keep the processing rate under the assigned maximum rate allocation.

BAR file

The maximum rate is set within the BAR file under a property called maximumRateMsgsPerSec.

The property can be set in the following ways:

• Within the BAR file through the IBM® Integration Toolkit editor.
  Note: You must refresh the content of a migrated BAR file before you can see and configure the maximumRateMsgsPerSec property. For more information, see Refreshing the contents of a broker archive.
• Within the BAR file through the IBM Integration Explorer.
• Within the BAR file through the mqsiapplybaroverride command line.
  Note: For example, to set the maximumRateMsgsPerSec property for a message flow included in an application, you can use the following sample code:

  mqsiapplybaroverride –b BARfile -k applicationName -m sampleFlow#maximumRateMsgsPerSec=100 

  For more information, see mqsiapplybaroverride command.

Additionally, once the BAR file is deployed, the property can be set dynamically within the flow through the IBM Integration API. Any change to the property is picked up immediately and does not require the flow to be restarted.

Workload management policy

Details of how to create and configure a workload management policy are described in Configure a workload management policy within Integration Registry.

A maximum rate value of zero, or not set, causes the message flow maximum rate to be turned off. The default state is off.

Within the same integration server, a mixture of message flows can run along side each other, some with the maximum rate set, others with the maximum rate turned off.