What are the functions of RocketMq
First answer the general functions of the message middleware
1. Business decoupling: This is also the message model of publish and subscribe. The producer sends instructions to MQ, and then downstream consumers who subscribe to such instructions will receive this instruction to execute the corresponding logic. The whole process has nothing to do with the specific business. It is abstracted into a process of sending instructions, storing instructions, and consuming instructions.
2. Front-end peak clipping: Too many requests initiated by the front-end can not be processed by the back-end in a short time, which can be accumulated in MQ, and the back-end is processed in a certain order. This is how the spike system is implemented.
Let's talk about the characteristics of RocketMq:
3, million-level message accumulation capacity, the cumulative capacity of million-level messages in a single queue.
4. High availability: The Broker server supports synchronous dual-write with multiple masters and multiple slaves and asynchronous replication mode with multiple masters and multiple slaves, in which synchronous double-write can ensure that messages are not lost.
5. High reliability: There are three ways for the producer to send the message to the Broker, synchronous, asynchronous and one-way. Both synchronous and asynchronous can ensure the successful sending of the message. Broker has two strategies for message flashing: synchronous flashing and asynchronous flashing. Synchronous flashing can ensure that messages are successfully stored on the disk. There are also two types of consumer consumption patterns: cluster consumption and broadcast consumption. The default is cluster consumption. If a consumer fails in the cluster mode, other consumers in a group will take over their consumption. In summary, it is highly reliable.
6. Support for distributed transaction messages: here is the use of semi-message confirmation and message back-check mechanisms to ensure distributed transaction messages, which will be described in detail below.
7. Support message filtering: It is recommended to use tag filtering on the consumer business side.
8. Support sequential messages: Messages are stored in the FIFO mode of queues in the Broker, that is, the transmission is sequential, as long as the order of consumption is guaranteed.
9. Support timing messages and delayed messages: The mechanism of timing messages in the Broker, the messages sent to the Broker will not be consumed by the Consumer immediately, and will be consumed after a certain period of time. The same is true for delayed messages, which will be consumed by Consumer only after a certain delay.