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Message Queue Introduction A message is the data being transmitted Message Queue is a form of communication that can be returned immediately after sending a message There is a messaging system to ensure reliable delivery of messages Message publishers can only publish messages to MQ without having to care about others Message consumers ...

Here, let's sort out the relevant knowledge of consumeGroup 1. First, we will set groupId for each consumer. Consumers with the same groupId and subscribed to the same topic will form a consumeGroup, as shown in Figure 1 2. For the topic on the Server side, there is the concept of partition, as shown in Figure 2 3. Now we have multiple con ...

catalogue Fundamentals: distributed locks Why do I need distributed locks? Characteristics of distributed locks Common scenarios Redis implements distributed locks Redisson distributed lock entry practice reference Fundamentals: distributed locks The synchronized keyword and ReentrantLock reentrant lock in Java can control concurrent ...

1, Zookeeper cluster operation Objective: deploy Zookeeper on Hadoop 101, Hadoop 102 and Hadoop 103 nodes. 1.1 decompression and installation In Hadoop 101, unzip the Zookeeper installation package to the / usr/local / directory decompression [root@hadoop101 local]# tar -zxvf apache-zookeeper-3.6.3-bin.tar.gz Delete compressed package [roo ...

1, Introduction 1, Overview Netty is an open source framework provided by JBOSS. In essence, it is a network application framework. It provides a non blocking and event driven network application framework and tools to facilitate the rapid development of high-performance and reliable network server and client. 2, Core architecture         ...

redission 1,pom.xml <dependency> <groupId>org.redisson</groupId> <artifactId>redisson</artifactId> <version>version</version> </dependency> 2,redissionUtils public class RedissionUtils { private static Logger logger = LoggerFactory.getLogger(RedissionUtils.class); private static ...

1, Interface idempotency Interface idempotency means that the results of one request or multiple requests initiated by the user for the same operation are consistent, and there will be no side effects due to multiple clicks. The simplest example is payment. The user pays after purchasing goods, and the payment is deducted successfully. However ...

background The day before yesterday, my colleague reported that there was a problem with the redis distributed lock, resulting in duplicate order numbers. Later, everything was normal after it was replaced with reission. Based on this phenomenon, this paper analyzes it Problem driven The following code is analyzed and three problems are foun ...

1. Distributed lock 1.1 what is distributed lock When we develop a stand-alone application involving concurrent synchronization, we often use synchronized or ReentrantLock to solve the problem of code synchronization between multiple threads. However, when our application works in a distributed cluster, we need a more advanced locking m ...

1. Log information of the sweep 2. Common configuration of scratch ROBOTSTXT_ Whether obey complies with the robots protocol. The default is compliance About robots protocol In Baidu search, you can't search the details page of a specific commodity on Taobao. This is the robots protocol at workRobots protocol: the website tells se ...