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As shown in the title, this paper focuses on sequential messages, delayed messages and message filtering.1, Sequential messageRocketMQ can only ensure the order of messages at the queue level. If you want to realize the sequential execution of a certain type of messages, you must send such messages to the same queue. You can use MessageQueueSel ...

For data storage, RocketMQ uses the file programming model. In order to improve the writing performance of files, the memory mapping mechanism is usually introduced. The data is written to the page cache first, and then the page cache data is flushed to the disk. The performance and data reliability involved in writing must be considered. For t ...

The above is a picture found on the official website. After the producer sends the message, the broker generates the commitlog and ConsumerQueue files, and then the consumer obtains the message according to the starting physical address + message size in the commitlog in the ConsumerQueue, and then obtains the message for consumption.The follow ...

Summary of JAVA back-end development knowledge (continuous update...) RocketMQ concept and usage 1, Overview    MetaQ is a distributed message middleware with Queue model. Based on publish and subscribe mode, it supports two modes: Topic and Queue. There are two consumption modes: Push and Pull. It supports strict message ...

Write in front In our daily development, we often encounter the business scenario of "triggering an event after a period of time". For example: If the e-commerce platform does not pay within 30 minutes after placing an order, the order will be automatically cancelledRed envelopes will not be collected for 24 hours and will be return ...

This article mainly involves the following contents when sending a message:Queue selection mechanism for sequential messagesRocketMQ keyRocketMQ tagRocketMQ msgIdQueue selection mechanism for sequential messagesIn many business scenarios, it is necessary to ensure the sequential processing of messages. For example, when orders flow to different ...

catalogue Producer Product Consumer I have learned the basic knowledge of Rocket and set up MQ stand-alone version and cluster environment. Now I will start the actual development and explain the basic use of RocketMQ according to the RocketMQ source code downloaded earlier: Producer Product In the example subproject of RocketMq's source ...

Project scenario: As I know, the project we are working on now has many external interfaces for the agent to call, but the response of some interfaces is not returned in real time. At this time, we need to respond to the agent by calling back the interface. During this period, other situations such as network instability may occur, resulting i ...

Grain mall advanced level chapter Content directory: 1, ElasticSearch 1.1 introduction to elasticserch: Full text search is the most common requirement. Open source Elasticsearch is the first choice of full-text search engines. It can quickly store, search and analyze massive data. Wikipedia, Stack Overflow and Github all use it. The bo ...

Message queue FreeRTOS learning warehouse address: https://gitee.com/killerp/free-rtos_-study Message queue is the basic data structure of RTOS, which is used for data transmission between tasks and between tasks and interrupts. When message queuing is not used, if you want to transfer data between two tasks, you must transfer it throug ...