Tuning SOAP processing for scalability and performance

When processing SOAP messages, you can improve performance by configuring the number of additional instances on the message flow. This configuration increases the number of available threads for processing messages on that node and allows parallel processing of messages. You can configure the number of additional instances at message flow level or on the node itself.

However, when using SOAP with WS-RM (web services reliable messaging), increasing the number of additional instances does not always affect the rate at which messages are processed. If the message flow is processing a group of messages from a single sequence and the WS-RM InOrder assurance is enabled, all the messages from that sequence are processed by a single instance of the message flow, even if additional instances are configured.

This ensures that messages are processed in the order in which they were sent, but means that the rate of processing stays the same for the messages in that sequence. In this example, the SOAP message flow with WS-RM enabled processes messages from multiple inbound sequences in parallel, but it processes only one request at a time for messages from the same inbound sequence.

For more information about the concepts of WS-RM, read Web Services Reliable Messaging.