search
HomeDatabaseRedisHow to use Redis locks to deal with concurrency issues

How to use Redis locks to deal with concurrency issues

Use Redis lock to handle concurrency issues to ensure that only one instance of multiple processes is running. When the running instance goes down, one of the other instances can come up, ensuring that there is and only There is an instance running.

import redis
r = redis.Redis(...)

last_heart = 0		# 记录上一次得到的锁心跳
free_lock_try = 6	# 锁无心跳的最大次数 

while not r.setnx('mylock', 1):
    now_heart = r.get('mylock')
    print(f"没获取到锁,now_heart={now_heart},last_heart={last_heart},free_lock_try={free_lock_try}")
    if now_heart == last_heart:
        free_lock_try = free_lock_try - 1
        if free_lock_try == 0:	# 锁已经1分钟没有心跳了
            old_heart = r.getset('mylock', 1)	# 将lock重置为1,并返回set之前的心跳值
            if old_heart < now_heart:
                time.sleep(10)
                continue
            else:
                break	# 成功获取到锁,退出循环
    else:
        free_lock_try = 6	# 锁有心跳,重置free_lock_try值
        last_heart = now_heart
    time.sleep(10)

def producer_exit():
    """程序正常退出时候自动清理锁"""
    r.delete(&#39;mylock&#39;)
import atexit
atexit.register(producer_exit)

# 业务代码
while True:
  r.incr(&#39;mylock&#39;)	# 让锁心跳加一
  ...

Let’s take a look at what problems this program solves in concurrent locks:

1. Under high concurrency, multiple processes cannot obtain locks at the same time. Redis.setnx is used here. If the lock already exists, other processes cannot reset the lock and obtain the lock. In addition, when multiple processes find that there is a lock and no heartbeat at the same time, they use redis.getset to reset the heartbeat to 1. The set can be successful, but the value obtained by multiple processes is different. Only the lock is actually acquired. The process returns the heartbeat of the previous process, while other processes get 1.

2. The process with the lock exits normally. You can use atexit to register the process exit function to delete the lock. You don’t need to do it here, but you will have to wait for the new process to wait for several heartbeats when starting next time.

3. The locked process exits unexpectedly, and the heartbeat will no longer increase after exiting. After the number of free_lock_try is exceeded, other processes will reset and acquire the lock

4. All processes exit unexpectedly. This problem is not of concern to locks. You can use Supervisor performs the daemon process.

For more redis knowledge, please pay attention to the redis introductory tutorial column.

The above is the detailed content of How to use Redis locks to deal with concurrency issues. For more information, please follow other related articles on the PHP Chinese website!

Statement
This article is reproduced at:haofly. If there is any infringement, please contact admin@php.cn delete
Redis's Role: Exploring the Data Storage and Management CapabilitiesRedis's Role: Exploring the Data Storage and Management CapabilitiesApr 22, 2025 am 12:10 AM

Redis plays a key role in data storage and management, and has become the core of modern applications through its multiple data structures and persistence mechanisms. 1) Redis supports data structures such as strings, lists, collections, ordered collections and hash tables, and is suitable for cache and complex business logic. 2) Through two persistence methods, RDB and AOF, Redis ensures reliable storage and rapid recovery of data.

Redis: Understanding NoSQL ConceptsRedis: Understanding NoSQL ConceptsApr 21, 2025 am 12:04 AM

Redis is a NoSQL database suitable for efficient storage and access of large-scale data. 1.Redis is an open source memory data structure storage system that supports multiple data structures. 2. It provides extremely fast read and write speeds, suitable for caching, session management, etc. 3.Redis supports persistence and ensures data security through RDB and AOF. 4. Usage examples include basic key-value pair operations and advanced collection deduplication functions. 5. Common errors include connection problems, data type mismatch and memory overflow, so you need to pay attention to debugging. 6. Performance optimization suggestions include selecting the appropriate data structure and setting up memory elimination strategies.

Redis: Real-World Use Cases and ExamplesRedis: Real-World Use Cases and ExamplesApr 20, 2025 am 12:06 AM

The applications of Redis in the real world include: 1. As a cache system, accelerate database query, 2. To store the session data of web applications, 3. To implement real-time rankings, 4. To simplify message delivery as a message queue. Redis's versatility and high performance make it shine in these scenarios.

Redis: Exploring Its Features and FunctionalityRedis: Exploring Its Features and FunctionalityApr 19, 2025 am 12:04 AM

Redis stands out because of its high speed, versatility and rich data structure. 1) Redis supports data structures such as strings, lists, collections, hashs and ordered collections. 2) It stores data through memory and supports RDB and AOF persistence. 3) Starting from Redis 6.0, multi-threaded I/O operations have been introduced, which has improved performance in high concurrency scenarios.

Is Redis a SQL or NoSQL Database? The Answer ExplainedIs Redis a SQL or NoSQL Database? The Answer ExplainedApr 18, 2025 am 12:11 AM

RedisisclassifiedasaNoSQLdatabasebecauseitusesakey-valuedatamodelinsteadofthetraditionalrelationaldatabasemodel.Itoffersspeedandflexibility,makingitidealforreal-timeapplicationsandcaching,butitmaynotbesuitableforscenariosrequiringstrictdataintegrityo

Redis: Improving Application Performance and ScalabilityRedis: Improving Application Performance and ScalabilityApr 17, 2025 am 12:16 AM

Redis improves application performance and scalability by caching data, implementing distributed locking and data persistence. 1) Cache data: Use Redis to cache frequently accessed data to improve data access speed. 2) Distributed lock: Use Redis to implement distributed locks to ensure the security of operation in a distributed environment. 3) Data persistence: Ensure data security through RDB and AOF mechanisms to prevent data loss.

Redis: Exploring Its Data Model and StructureRedis: Exploring Its Data Model and StructureApr 16, 2025 am 12:09 AM

Redis's data model and structure include five main types: 1. String: used to store text or binary data, and supports atomic operations. 2. List: Ordered elements collection, suitable for queues and stacks. 3. Set: Unordered unique elements set, supporting set operation. 4. Ordered Set (SortedSet): A unique set of elements with scores, suitable for rankings. 5. Hash table (Hash): a collection of key-value pairs, suitable for storing objects.

Redis: Classifying Its Database ApproachRedis: Classifying Its Database ApproachApr 15, 2025 am 12:06 AM

Redis's database methods include in-memory databases and key-value storage. 1) Redis stores data in memory, and reads and writes fast. 2) It uses key-value pairs to store data, supports complex data structures such as lists, collections, hash tables and ordered collections, suitable for caches and NoSQL databases.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

SecLists

SecLists

SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

WebStorm Mac version

WebStorm Mac version

Useful JavaScript development tools

Atom editor mac version download

Atom editor mac version download

The most popular open source editor

EditPlus Chinese cracked version

EditPlus Chinese cracked version

Small size, syntax highlighting, does not support code prompt function

DVWA

DVWA

Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software