Serial Processing in a Cluster or Non-Clustered Group of Integration Servers

Serial document processing determines how the messaging provider distributes guaranteed documents to the individual servers within a cluster or non-clustered group. In a cluster or non-clustered group, the individual Integration Servers share the same client. For example, if the messaging provider is the webMethods Broker, the servers act as a single webMethods Broker client and share the same trigger client queues and document subscriptions. With serial processing, servers in a cluster or non-clustered group can process documents from a publisher in the same order in which the documents were published.

Note: In addition to the term “non-clustered group,” the terms “stateless cluster” and “external cluster” are sometimes used to describe the situation in which a group of Integration Servers function in a manner similar to a cluster but are not part of a configured cluster.

For each webMethods messaging trigger, each server in the cluster or non-clustered group maintains a trigger queue in memory. This allows multiple servers to process documents for a single webMethods messaging trigger. The messaging provider manages the distribution of documents to the individual webMethods messaging triggers in the cluster or non-clustered group.

How the messaging provider distributes documents for a serial trigger on the Integration Servers in the cluster or group to ensure that documents from a single publisher are processed in publication order varies:

webMethods Broker distributes documents so that the Integration Servers in the cluster or non-clustered group process guaranteed documents from a single publisher in the same order in which the documents were published. Multiple Integration Servers can process documents for a single trigger, but only one Integration Server in the cluster or non-clustered group processes documents for a particular publisher. For more information, see Serial Processing with the webMethods Broker in a Clustered or a Non-Clustered Group of Integration Servers

Universal Messaging distributes all the documents to which a particular serial trigger subscribes to the same Integration Server in a cluster or non-clustered group. Regardless of the document publisher, all of the published documents to which a specific serial trigger subscribes are received and processed by the same Integration Server. Because a serial trigger processes only one document at a time, this distribution approach ensures that documents are processed in the same order in which they were published. For more information, see Serial Processing with Universal Messaging in a Clustered or a Non-Clustered Group of Integration Servers.