1. A Small Requirement We run into small requirements all the time, but they are not always simple to implement. Here is a simple file upload requirement, broken into the following steps: The user uploads a large file on the page The large file is temporarily stored in the internal

1. Where a Message Queue Fits 1.1 Asynchronous Processing Use case: after a user registers, a registration email and a registration SMS must be sent. With the synchronous approach, system performance (concurrency, throughput, response time) hits a bottleneck. 1.2 Application Decoupling Use case: after a user places an order, the

Scenario one: the company is preparing to push an email announcement to all employees. Using a wrapped mail library API and looping over every employee to push the emails will leave the main program stuck in the loop and unable to respond, which is not what we want — we want to be able to carry on with other operations normally after clicking execute.