In serial processing, Integration Server processes the documents received by a webMethods messaging trigger one after the other. Integration Server retrieves the first document received by the webMethods messaging trigger, determines which condition the document satisfies, and executes the service specified in the webMethods messaging trigger condition. Integration Server waits for the service to finish executing before retrieving the next document received by the webMethods messaging trigger.

For a webMethods messaging trigger with serial processing, Integration Server processes documents in the same order in which the trigger retrieves the documents from the messaging provider. However, Integration Server processes documents for a serial trigger more slowly than it processes documents for a concurrent trigger.

If your webMethods messaging trigger contains multiple conditions to handle a group of published documents that must be processed in a specific order, use serial processing. This is sometimes called ordered service execution. Only triggers that receive messages from webMethods Broker can perform ordered service execution.

When a webMethods messaging trigger receives documents from webMethods Broker, the queue for the serial trigger on the webMethods Broker has a Shared Document Order mode of “Publisher”.

When a webMethods messaging trigger receives documents from Universal Messaging, the durable subscription for a trigger with serial processing is a serial durable subscription. That is, in Universal Messaging Enterprise Manager, the durable subscription for the trigger has the Serial check box selected.

When receiving messages from Universal Messaging, the Universal Messaging window size limits the number of documents that can be processed at one time by an individual trigger. To ensure that a serial trigger processes documents in order, Integration Server sets the window size of a client queue for a serial trigger is set to 1. The window size set for a trigger overrides the default value specified in Universal Messaging.