Java Projects - Second Edition

Back-pressure

Message handling, with the appropriate messaging interfaces and implementation, supports back-pressure. Back-pressure is a means to lessen the burden on a component when it cannot or can barely handle more messages. Messages may be queued for processing, but no real-life queue has unlimited capacity, and reactive systems should not lose a message that's uncontrolled. Back-pressure signals the load of the component to the message producers, asking them to lessen the production. It is like a water pipe. If you start closing the outlet of the pipe, the pressure starts to increase in the pipe backwards, the water source forcing it to deliver less and less water.

Back-pressure is an effective way of handling load because it moves ...