How Redis implements distributed caching function

How Redis implements the distributed cache function requires specific code examples

Abstract: Redis is a high-performance data caching and storage system that has distributed characteristics. Can support distributed cache function. This article will introduce how Redis implements distributed caching and provide specific code examples to help readers understand.

1. Overview
   Distributed cache is a caching system that stores data dispersedly on multiple nodes. It speeds up data access by storing data closer to the application. Speed ​​and response time. Redis implements the distributed cache function by using cluster mode.
2. Redis cluster mode
   Redis cluster is a distributed system composed of multiple nodes, each node is responsible for storing and processing a part of the data. The nodes in the cluster communicate through the Gossip protocol, realizing automatic data sharding and automatic node discovery.

In the Redis cluster, data is automatically divided into multiple slots, and each slot is managed by a node. By computing the hash of a key, you can determine which slot it belongs to and thus find the node where it is stored. When a key needs to be accessed, the application sends the request to the corresponding node.

3. Redis distributed cache implementation
   Redis implements the distributed cache function by using cluster mode. In a cluster, each node can store cached data. When data needs to be stored in the cache, the application sends the data to the corresponding node. When it is necessary to access cached data, the application will first calculate the hash value of the key, determine the slot and node to which it belongs, and then send the request to the corresponding node.

The specific code example is as follows:

// 引入Redis库
const Redis = require('ioredis');

// 创建Redis集群客户端
const cluster = new Redis.Cluster([{
    host: 'node1.example.com',
    port: 6380
}, {
    host: 'node2.example.com',
    port: 6380
}, {
    host: 'node3.example.com',
    port: 6380
}]);

// 设置缓存数据
cluster.set('key1', 'value1');

// 获取缓存数据
cluster.get('key1')
    .then(value => {
        console.log(value);
    })
    .catch(error => {
        console.error(error);
    });

In the above code, we first introduced the ioredis library, which is the Node.js client of Redis. Then we created a Redis cluster client and specified the address and port number of the nodes in the cluster. We can then use this client to set and get cached data.

4. Summary
   By using Redis cluster mode, we can store data dispersedly on multiple nodes to achieve the function of distributed caching. Redis provides a simple and easy-to-use API to operate distributed cache, allowing us to more conveniently use cache to improve application performance and response speed. I hope this article can help readers understand the implementation of Redis distributed cache and apply it in actual projects.

Reference:

• Redis official documentation: https://redis.io/documentation

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