An activation ID is a unique identifier assigned to a published document. Subscribing triggers use the activation ID to determine whether a document satisfies a join condition. Integration Server stores the activation ID in the activation field of a document envelope.

By default, Integration Server assigns the same activation ID to each document published within a single top-level service. For example, suppose the processPO service publishes a newCustomer document, a checkInventory document, and a confirmOrder document. Because all three documents are published within the processPO service, Integration Server assigns all three documents the same activation ID.

You can override the default behavior by assigning an activation ID to a document manually. For example, in the pipeline, you can map a variable to the activation field of the document. If you want to explicitly set a document’s activation ID, you must set it before publishing the document. When publishing the document, the Integration Server will not overwrite an explicitly set value for the activation field.

You need to set the activation ID for a document only when you want a trigger to join together documents published by different services. If a trigger will join together documents published within the same execution of a service, you do not need to set the activation ID. Integration Server automatically assigns all the documents the same activation ID.