Expiration strategy of Redis
Redis mainly has two expiration deletion strategies
Lazy deletion
Lazy deletion refers to when we query the key The key is detected only when the expiration time has been reached, and then deleted. Obviously, one of its disadvantages is that if these expired keys are not accessed, they will never be deleted and will continue to occupy memory.
Periodic deletion
Periodic deletion means that redis checks the database every once in a while and deletes the expired keys. Since it is impossible to poll all keys for deletion, redis will randomly select some keys for checking and deletion each time.
The above is the detailed content of What is the expiration policy in Redis. For more information, please follow other related articles on the PHP Chinese website!
Redis: A Guide to Key-Value Data StoresMay 02, 2025 am 12:10 AMRedis is an open source memory data structure storage used as a database, cache and message broker, suitable for scenarios where fast response and high concurrency are required. 1.Redis uses memory to store data and provides microsecond read and write speed. 2. It supports a variety of data structures, such as strings, lists, collections, etc. 3. Redis realizes data persistence through RDB and AOF mechanisms. 4. Use single-threaded model and multiplexing technology to handle requests efficiently. 5. Performance optimization strategies include LRU algorithm and cluster mode.
Redis: Caching, Session Management, and MoreMay 01, 2025 am 12:03 AMRedis's functions mainly include cache, session management and other functions: 1) The cache function stores data through memory to improve reading speed, and is suitable for high-frequency access scenarios such as e-commerce websites; 2) The session management function shares session data in a distributed system and automatically cleans it through an expiration time mechanism; 3) Other functions such as publish-subscribe mode, distributed locks and counters, suitable for real-time message push and multi-threaded systems and other scenarios.
Redis: Exploring Its Core Functionality and BenefitsApr 30, 2025 am 12:22 AMRedis's core functions include memory storage and persistence mechanisms. 1) Memory storage provides extremely fast read and write speeds, suitable for high-performance applications. 2) Persistence ensures that data is not lost through RDB and AOF, and the choice is based on application needs.
Redis's Server-Side Operations: What It OffersApr 29, 2025 am 12:21 AMRedis'sServer-SideOperationsofferFunctionsandTriggersforexecutingcomplexoperationsontheserver.1)FunctionsallowcustomoperationsinLua,JavaScript,orRedis'sscriptinglanguage,enhancingscalabilityandmaintenance.2)Triggersenableautomaticfunctionexecutionone
Redis: Database or Server? Demystifying the RoleApr 28, 2025 am 12:06 AMRedisisbothadatabaseandaserver.1)Asadatabase,itusesin-memorystorageforfastaccess,idealforreal-timeapplicationsandcaching.2)Asaserver,itsupportspub/submessagingandLuascriptingforreal-timecommunicationandserver-sideoperations.
Redis: The Advantages of a NoSQL ApproachApr 27, 2025 am 12:09 AMRedis is a NoSQL database that provides high performance and flexibility. 1) Store data through key-value pairs, suitable for processing large-scale data and high concurrency. 2) Memory storage and single-threaded models ensure fast read and write and atomicity. 3) Use RDB and AOF mechanisms to persist data, supporting high availability and scale-out.
Redis: Understanding Its Architecture and PurposeApr 26, 2025 am 12:11 AMRedis is a memory data structure storage system, mainly used as a database, cache and message broker. Its core features include single-threaded model, I/O multiplexing, persistence mechanism, replication and clustering functions. Redis is commonly used in practical applications for caching, session storage, and message queues. It can significantly improve its performance by selecting the right data structure, using pipelines and transactions, and monitoring and tuning.
Redis vs. SQL Databases: Key DifferencesApr 25, 2025 am 12:02 AMThe main difference between Redis and SQL databases is that Redis is an in-memory database, suitable for high performance and flexibility requirements; SQL database is a relational database, suitable for complex queries and data consistency requirements. Specifically, 1) Redis provides high-speed data access and caching services, supports multiple data types, suitable for caching and real-time data processing; 2) SQL database manages data through a table structure, supports complex queries and transaction processing, and is suitable for scenarios such as e-commerce and financial systems that require data consistency.
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft
MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.
PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool
Zend Studio 13.0.1
Powerful PHP integrated development environment
mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),
