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 the documents to which a particular serial trigger subscribes across all the Integration Servers in a cluster or non-clustered group but allows processing by only one Integration Server in the cluster or group at a time. Because a serial trigger processes only one document at a time across the cluster or group, 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.