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Detailed explanation of distributed transactions implemented by Redis

With the continuous growth of Internet transactions, distributed transactions have become an essential part of business systems. With the continuous enrichment of distributed transaction implementation methods, Redis, as a widely used in-memory database, is gradually becoming the first choice for distributed transaction implementation. This article mainly introduces how Redis implements distributed transactions. Redis transaction model The transaction model supported by Redis is batch operation. Within a transaction, Redis can execute multiple commands. Multiple commands all succeed or fail in the same transaction, ensuring that the transaction

Jun 20, 2023 am 08:01 AM

分布式redis事务

How to use Redis's RDB and AOF methods

Redis persistence solution Redis is an in-memory database, and data is stored in memory. In order to avoid permanent loss of data due to process exit, the data in Redis needs to be regularly saved from memory to the hard disk in some form (data or commands). When Redis restarts next time, use the persistent file to achieve data recovery. In addition, persistent files can be copied to a remote location for disaster backup purposes. Redis provides multiple different levels of persistence: one is RDB and the other is AOF. RDB persistence can generate a point-in-time snapshot of the data set within a specified time interval, and save the database snapshot to

Jun 05, 2023 pm 12:31 PM

redisrdbaof

How to check Redis benchmark parameters

Redis comes with a tool called redis-benchmark to simulate N clients issuing M requests at the same time. (similar to the Apacheab program). You can use redis-benchmark-h to view benchmark parameters. The following parameters are supported: Usage:redis-benchmark[-h][-p][-c][-n[-k]-hServerhostname(default127.0.0.1)-pServerport(default6379)-sServersocket(overrideshostandport)-cNumberofparal

Jun 04, 2023 pm 12:12 PM

redis

What is the event-driven model of Redis?

Why doesn't Redis use the basic Socket programming model? When using the Socket model to implement network communication, you need to go through multiple steps such as creating a Socket, listening to ports, processing connections, and reading and writing requests. Now we will take a closer look at the key operations in these steps to help us analyze the Socket model. insufficient. First, when we need to communicate between the server and the client, we can create a listening socket (ListeningSocket) that listens to client connections on the server through the following three steps: call the socket function to create a socket. We usually call this socket an active socket (ActiveSocket); call the bind function,

Jun 04, 2023 am 10:20 AM

redis

How to implement concurrent queuing based on redis optimistic locking

There is a demand scenario where redis is used to control the number of scrapy runs. When the system background is set to 4, scapry is only allowed to start 4 tasks, and excess tasks are queued. Overview I recently built a django+scrapy+celery+redis crawler system. In addition to running other programs, the host purchased by the customer also needs to run the program I developed, so it is necessary to manually control the number of scrapy instances to avoid too many crawlers. Put a burden on the system. Process design 1. The crawler task is initiated by the user in the form of a request, and all user requests are uniformly entered into celery for queuing; 2. The execution of task number control is handed over to reids and saved through celery

Jun 04, 2023 am 09:58 AM

redis

How SpringBoot uses RedisTemplate to operate Redis data types

Spring encapsulates RedisTemplate to operate Redis, which supports all Redis native APIs. Operation methods for five data structures are defined in RedisTemplate. opsForValue(): operates on strings. opsForList(): Operation list. opsForHash(): operates hash. opsForSet(): Operation set. opsForZSet(): operates an ordered set. Below are examples to understand and apply these methods. What needs special attention here is that the data must be cleared after running the above method, otherwise running it multiple times will result in repeated data operations. (1) Use Maven to add dependency files

Jun 04, 2023 am 09:43 AM

redisTemplateredistemplate

How to use Redis's expiration strategy and memory elimination strategy

1. Set keyexpirekeyseconds with expiration time. Time complexity: O(1) Set the expiration time of key. After timeout, the key will be automatically deleted. In Redis terminology the timeout associated with a key is volatile. After timeout, it will only be cleared when DEL, SET, or GETSET is executed on the key. This means that conceptually all operations that change the key without replacing it with a new value will keep the timeout unchanged. For example, using INCR to increment the value of a key, executing LPUSH to push a new value into a list, or using HSET to change a hash field will keep the timeout unchanged. Use the PERSIST command to clear the timeout so that it

Jun 04, 2023 am 09:14 AM

redis

How to solve Redis related problems

Redis persistence mechanism Redis is an in-memory database that supports persistence. It synchronizes data in memory to hard disk files through the persistence mechanism to ensure data persistence. When Redis is restarted, the data can be restored by reloading the hard disk files into the memory. Implementation: Create a fork() child process separately, copy the database data of the current parent process to the memory of the child process, and then write it to a temporary file by the child process. After the persistence process is over, replace it with this temporary file. snapshot file, then the child process exits and the memory is released. RDB is the default persistence method of Redis. According to a certain time period strategy, the memory data is saved to a binary file on the hard disk in the form of a snapshot. That is Sn

Jun 04, 2023 am 08:33 AM

redis

What are the technical points of Redis?

1. Why use Redis? The author believes that using Redis in a project is mainly considered from two perspectives: performance and concurrency. Of course, Redis also has other functions that can do distributed locks and other functions, but if it is just for other functions such as distributed locks, there are other middleware (such as Zookpeer, etc.) that can be used instead, and it is not necessary to use Redis. Therefore, this question is mainly answered from two perspectives: performance and concurrency: 1. Performance is shown in the figure below. When we encounter SQL that takes a particularly long time to execute and the results do not change frequently, it is especially suitable to put the running results in into cache. In this way, subsequent requests will be read from the cache, so that requests can be responded to quickly. Off topic: I suddenly want to talk about this quick response

Jun 04, 2023 am 08:27 AM

redis

Redis cluster instance analysis

1. WhyK8s1. Resource isolation. The current RedisCluster is deployed on a physical machine cluster. In order to improve resource utilization and save costs, Redis clusters of multiple business lines are mixed. Because there is no CPU resource isolation, it often happens that the CPU usage of a Redis node is too high, causing other Redis cluster nodes to compete for CPU resources, causing delay jitter. Because different clusters are mixed, such problems are difficult to locate quickly and affect operation and maintenance efficiency. K8s containerized deployment can specify CPUrequest and CPUlimit, which improves resource utilization and avoids resource contention. 2. Automated deployment The current deployment process of RedisCluster on physical machines is very cumbersome.

Jun 04, 2023 am 08:21 AM

redis

How to configure sequence and deserialization of RedisTemplate in Redis

RedisTemplate configuration sequence and deserialization For redis operations, springboot has a good encapsulation, that is springdataredis. A highly encapsulated RedisTemplate class is provided to perform a series of redis operations, and the connection pool is automatically managed; at the same time, the transaction encapsulation operation is handed over to the container for processing. For the "serialization and deserialization" of data, multiple strategies (RedisSerializer) are provided. The default is to use JdkSerializationRedisSerializer, as well as StringRedisSerializer and JacksonJsonR.

Jun 03, 2023 pm 09:25 PM

redisredistemplate

What are the methods of using Redis integer collection?

1. Overview of Sets For sets, I believe everyone is familiar with STL's set. Its underlying implementation is a red-black tree. Regardless of insertion, deletion, or search, the time complexity is O(logn). Of course, if a hash table is used to implement a collection, insertion, deletion, and search can all reach O(1). So why does the collection use red-black trees and not hash tables? I think the biggest possibility is based on the characteristics of the set itself. The set has its own unique operations: intersection, union, and difference. These three operations are all O(n) for hash tables. Based on this, it is more appropriate to use an ordered red-black tree than an unordered hash table. 2. Redis integer set (intset) The integer set we are going to talk about today, also called intset, is Redis

Jun 03, 2023 pm 09:18 PM

redis

What is the command to check the redis version in Linux?

Two commands to check the redis version on Linux 1, redis-server–version and redis-server-v2, redis-cli–version and redis-cli-v

Jun 03, 2023 pm 08:58 PM

Linuxredis

How does redis realize real-time page updates and automatic online updates?

Requirement description: Some pages need to be configured with advertisements or event promotion images. Advertisements or activities need to be able to go online and offline at any time, automatically go offline after expiration, and automatically go online when the time comes. For example: the current time is 2019-2-2216:16:13. You need to configure the reward collection activity on the payment completion page. The activity must be online on time at 2019-3-1000:00:00 and end at 2019-3-3023:59:59. Activity. So the desired effect is that after configuring the activity at any time before the activity goes online, the page will automatically go online when the time comes. There may also be multiple other activities or advertisements. The number of advertisements on each page is variable, and the online and offline times may be different for different pages. Other pages also need to implement such functions, and the activities between pages are not necessarily the same. demand points

Jun 03, 2023 pm 08:56 PM

redis