11.3. Huge Messages and NodeModels

When a message is huge, you must identify its multiple NodeModels so that the runtime memory footprint is as low as possible. You cannot process the message using a single model because the full message is too big to hold in memory. In the case of the order message, there are two models: one for the main order data and one for the order-item data.

Most data that will be in memory at any one time is the main order data, plus one of the order-items. Because the NodeModels are nested, Smooks makes sure that the order data NodeModel never contains any of the data from the order-item NodeModels. Also, as Smooks filters the message, the order-item NodeModel will be overwritten for every order-item (that is, they are not collected).