This describes the application scenarios of MQ.
In the complicated multi-business system of an enterprise, many business processes don’t strongly depend on the core process, and can be placed in the JCQ for JCQ consumers to consume by need, without influencing the core primary process. Scenario: E-commerce scenario After the upstream business transaction system is completed, store the messages in the message queue, and the business system logistics, shopping cart, scores of the downstream will consume in the message queue, isolated from each other and processed in parallel, which ensures the final consistency between the distributed systems.
In case of a difference between the upstream and downstream system processing capacity, JCQ will be used as the data buffer to control the information traffic. Consumption will proceed when the downstream system is capable of processing, so as to avoid invalid request and no service capacity. Scenario: SecKil When the user is seckilling on the page, the frontend page respond immediately, a request is sent to Message Queue, the order or confirmation will be later fed back to the user, and the customer may close the webpage and carry out other activities.
The producer has no need to care about the downstream consumer who subscribes the message. The many-to-many broadcasting mode is adopted, and consumption messages may be sent and received simultaneously. Scenario 1: Task Allocation For distributed processing framework, use MQ to complete task allocation scheduling and the implementation of task processing. Scenario 2: Configuration Center Update The configuration center updates the configuration files, and sends the message on configuration update to Message Queue. Other servers regularly obtain the contents in Message Queue, and will go to the configuration center for update after they find that the configuration is updated.
Receivers may response requests sent by the upstream system after a long time and may not be able to receive such requests because of network, outage, overload and other reasons, while the synchronous writing and three-copy backup of message queue can store the requests to guarantee asynchronous and reliable transmission of messages and timeliness and reliability of requests. Scenario: Transfer of funds When a mass of transactions occur, the actual transaction system may not change the account values yet, but the transaction operation records will be saved for a long time and asynchronous system treatment is allowed until transactions are successfully completed.