This article introduces Redis as an open‑source, in‑memory data‑structure store, explains its role as a NoSQL database, details its five fundamental data types, common commands, expiration handling, pipelines, and transactions, and shows how it fits into modern scaling architectures.
Version 1.0.3 of the pure PHP coroutine Wind Framework introduces a new Chan class for intra-process coroutine messaging, enhances the message queue with Redis and Beanstalk drivers supporting massive consumer counts and timeout settings, and fixes several Beanstalk client command errors.
This article explains Redis persistence mechanisms, detailing how RDB snapshots and AOF append‑only logs work, how to enable and configure them, their advantages and drawbacks, and guidance on choosing the right method for reliable data storage.
The article recounts how Postman's Service Foundation team identified the limitations of the monolithic Sync service, designed and built the Bifrost WebSocket gateway using Fastify, AWS ElastiCache for Redis, and a private API, and scaled it through horizontal expansion and custom load‑factor metrics while sharing practical engineering insights.
This article demonstrates how to back up and restore Redis data using semi‑persistent RDB snapshots, full‑persistent AOF logging, and master‑slave replication, including command‑line examples for setting keys, checking replication status, saving snapshots, promoting a slave to master, and verifying data integrity.
The article outlines typical problems caused by inconsistent Redis master‑slave settings—such as mismatched maxmemory, differing hash‑ziplist parameters, replication performance bottlenecks, and single‑point failures—and provides practical recommendations to improve reliability and data safety.
This guide shows how to set up a complete Redis monitoring stack by launching two Redis instances, a redis‑exporter collector, and Grafana‑Prometheus visualisation all via Docker, covering container creation, IP discovery, configuration files, datasource setup and dashboard creation.
This guide explains three Redis migration methods, focuses on using the third‑party tools redis‑dump and redis‑load, and provides detailed steps to upgrade Ruby, install RVM, set up redis‑dump, and export/import data in JSON format.
Redis instances provide 16 default logical databases that act as namespaces rather than separate data stores; this article explains their origin, how to configure the number of databases, proper usage of SELECT and FLUSHALL commands, and why multiple databases are unsupported in Redis Cluster mode.
Redis can experience latency spikes due to factors such as complex commands, big keys, expiration patterns, memory limits, fork overhead, AOF persistence, CPU binding, swap usage, memory fragmentation, and network saturation, and this article provides a systematic troubleshooting methodology and practical optimization solutions for each scenario.
This article introduces Redis's primary data structures—String, Hash, List, and Set—explaining their purpose, key commands, and practical usage examples, including batch operations, numeric adjustments, field management, list manipulation, and set operations, to help developers effectively work with the in‑memory database.
This article explains how to use Redis INFO and related commands to monitor critical performance metrics such as memory usage, memory fragmentation, total commands processed, latency, and key eviction, and provides practical tips for interpreting these metrics and optimizing Redis deployments.
This article compiles essential interview‑style questions and detailed answers on distributed system fundamentals—including CAP and BASE theories, consistency models, distributed transactions, Redis features and persistence, Zookeeper coordination, Kafka architecture, and common design patterns for high‑concurrency scenarios.
This tutorial walks through building a Redis 6+ cluster on a single server, covering node startup, cluster handshake, slot assignment, master‑slave replication, command routing, failover handling, and practical scaling operations such as adding and removing nodes.
This article analyzes the characteristics of Redis and Memcached, explains typical design mistakes such as inconsistent hashing, cache avalanche, penetration, and hot‑key issues, and provides practical solutions like consistent hashing, binlog‑driven cache invalidation, key versioning, and distributed locking to improve cache reliability and performance.
This article details how JD.com designed, scaled, and refined its mask reservation backend during the COVID‑19 pandemic, addressing extreme traffic spikes, hot‑key issues, MySQL bottlenecks, and introducing a circuit‑breaker mechanism to protect the overall transaction system.
This article presents a cinema ticketing system built with the SSM framework, MySQL, Redis, Alipay sandbox, LayUI, and Baidu ECharts, highlighting its architecture, features such as payment and seat selection, and providing source code link and screenshots.
This comprehensive guide details the essential redis.conf parameters—including daemonization, networking, memory limits, logging, slowlog, advanced data structure encodings, replication options, and persistence settings—providing clear explanations and recommended values for optimal Redis deployment.
This article examines the challenges of building a flash‑sale (秒杀) system—such as overselling, massive concurrent requests, URL exposure, and database bottlenecks—and presents a comprehensive backend architecture that combines separate databases, dynamic URLs, static pages, Redis clustering, Nginx load balancing, SQL optimization, rate‑limiting, asynchronous order processing, and service degradation techniques.
This technical guide walks through the fundamentals of Prometheus, compares it with Zabbix, demonstrates high‑availability setups, remote storage with InfluxDB, multi‑instance Redis monitoring, and Grafana integration, providing concrete configuration examples and best‑practice recommendations for reliable ops monitoring.
This article explains how Redis can be used as a lightweight message‑queue solution by leveraging its List, Pub/Sub, and Stream data structures, covering core commands, blocking consumption, acknowledgment mechanisms, consumer groups, and practical usage patterns for distributed systems.
The article introduces go-mysql-transfer, a Go-implemented MySQL binlog incremental synchronization solution that avoids extra components, supports multiple downstreams like Redis, offers Lua scripting, Prometheus monitoring, high‑availability clustering, retry mechanisms, full data initialization, and provides installation, deployment, and performance testing details.
This article walks through three progressively better implementations for a complex e‑commerce search API—starting with a monolithic SQL query, then splitting the query and adding indexes, and finally using Redis sets and sorted sets to cache filter results, handle pagination, and achieve production‑grade performance.
This article explores the key challenges of designing a flash‑sale (秒杀) system—such as overselling, high concurrency, request flooding, and database strain—and presents a comprehensive backend architecture with database design, dynamic URLs, caching, rate limiting, async ordering, and service degradation techniques.
This article presents an interview scenario where a candidate is asked about Redis cache avalanche, explains the phenomenon, and offers four practical mitigation strategies—including cache pre‑warming, mutex locking, staggered expiration, and high‑availability designs—to keep backend databases from being overwhelmed.
Idempotency ensures that repeated API calls produce the same effect as a single call, preventing duplicate submissions, token misuse, and inconsistent data; this guide explains the concept, its importance, HTTP definitions, impact on systems, and presents four practical implementation methods—unique keys, optimistic locking, token‑based guards, and sequence numbers—with full SpringBoot and Redis code examples.
This tutorial walks through setting up a Redis Cluster on a single server with six nodes, covering node startup, handshake, slot assignment, master‑slave replication, command routing, failover handling, and practical scaling operations such as adding, rebalancing, and removing nodes.
This article explains the cardinality‑counting problem behind DAU/MAU and unique visitor metrics, compares naïve solutions like Set, Bitmap and Bloom filter, introduces big‑data algorithms such as Linear Counting, LogLog and HyperLogLog, and shows how Redis implements HyperLogLog with dense and sparse storage optimizations.
This article walks through the design, pitfalls, and deep optimizations of a Node.js + TypeScript backend that periodically syncs enterprise WeChat organization data to a MySQL store and provides a phone‑number lookup API, offering practical solutions for rate limits, process management, database conflicts, and error recovery.
The document provides a detailed technical overview of New Oriental's unified management platform, describing its five core modules—Redis platform, microservice platform, gateway platform, app management platform, and permission management platform—including monitoring, cluster management, service registration, and access control features.
The article explains the concepts of cache penetration, cache breakdown, and cache avalanche in Redis, illustrates each problem with real‑world analogies, and presents practical mitigation techniques such as null caching, Bloom filters, mutex locks, asynchronous refresh, varied TTLs, and clustering to ensure robust backend performance.
This article explains why Redis latency can suddenly increase, covering high‑complexity commands, large keys, concentrated expirations, memory limits, fork overhead, CPU binding, AOF settings, swap usage, and network overload, and provides concrete diagnostic commands and mitigation strategies.
This article explains Redis’s memory eviction policies, expiration strategies, common cache problems such as penetration, breakdown, and avalanche, outlines deployment modes, compares RDB and AOF persistence, and lists typical business scenarios for using Redis as a high‑performance key‑value store.
This article examines common causes of increased latency in Redis—including high‑complexity commands, large keys, concentrated expirations, memory limits, fork overhead, CPU binding, AOF settings, swap usage, and network saturation—and provides practical monitoring and configuration techniques to diagnose and reduce delays.
This article explores the design of a high‑concurrency train ticket‑seckill system, covering 12306 backend architecture, multi‑layer load balancing, Redis‑based stock deduction, Go code examples, performance testing, and strategies to prevent overselling and ensure fault tolerance.
This article explains why the Flask‑Redis extension cannot switch Redis databases, describes the underlying limitation of redis‑py, and provides a Python class library that enables dynamic database selection, data push/pull, and clean connection handling for Flask applications.
This tutorial walks you through installing JumpServer—a bastion host for centralized server management—by setting up MariaDB and Redis on separate nodes, configuring Docker, pulling the JumpServer image, generating required secret keys, and finally configuring users, groups, assets and session replay through the web UI.
This article explains the concepts of cache penetration, cache breakdown, and cache avalanche in Redis, presents common mitigation techniques such as request validation, empty‑value caching, Bloom filters, mutex locks, and high‑availability strategies, and includes Java code examples for practical implementation.
This article explains Redis persistence mechanisms, detailing how the in‑memory database can lose data on shutdown and how the two main durability options—RDB snapshots and AOF append‑only logs—work, their configuration commands, their advantages, disadvantages, and guidance on choosing the right approach for production use.
This article explains how Redis can be used to build lightweight, high‑performance message queues by leveraging lists for simple queues, sorted sets for delayed delivery, Pub/Sub for multicast, and the Stream data structure for durable, scalable messaging, while also covering practical PHP implementations, acknowledgment, retry, graceful restart, and rate‑limiting techniques.
This article recounts how a Tubi engineering team diagnosed a surprising latency increase after adding Redis cache to an Elixir manifest‑fetch API, identified a hidden CPU‑heavy Regex.replace/4 bug, applied targeted optimizations, and contributed a fix to the Elixir core.
This article explains how distributed lock requirements arise when scaling from monolithic to multi‑server architectures, reviews the evolution of Redis‑based locking mechanisms from simple SETNX to Lua scripts and Redisson's advanced features, and provides detailed source‑code analysis of Redisson's lock, unlock, and lock acquisition implementations.
This article describes how CTrip tackled rapid Redis cluster growth by moving from vertical scaling to a containerized horizontal splitting approach, then introduced a binlog‑server based horizontal expansion and shrinkage method that reduces operation time, eliminates data migration, supports both scaling up and down, and improves resource utilization.
This article provides a hands‑on guide to using IdentityServer4 in the Fuluteng project, covering signing credentials, client and resource stores, persisted grant storage with Redis, various OAuth2 grant types including client credentials, authorization code, password, and custom extensions such as SMS and third‑party logins, and demonstrates role‑based authorization and JWT configuration.
This article explains the benefits of short URLs, outlines their basic workflow, and details a backend design that uses an incremental issuer, base conversion, persistent storage, caching, batch ID allocation, and distributed issuers to achieve efficient, high‑concurrency short‑URL generation.
This article explains why short URLs are used in SMS and other platforms, outlines their benefits, describes the basic workflow of mapping long URLs to short ones, and dives into backend design choices such as incremental ID generation, storage strategies, caching, batch allocation, and distributed generation using Redis and Java.
This article evaluates and compares a range of Redis visualization tools—including desktop clients, web applications, and IDE plugins—by examining their features, usability, platform support, pricing, and command‑line integration to help developers choose the most suitable solution for their workflow.
This article presents thirteen practical Redis performance‑optimization rules—covering command complexity, key expiration, data structures, persistence, hardware choices, clustering, memory fragmentation, and client‑side techniques—to help developers identify bottlenecks and boost throughput and latency in production environments.
This comprehensive guide explores Redis internals, covering its core data types and their low‑level implementations, persistence mechanisms like RDB and AOF, performance tricks, common pitfalls such as cache avalanche and split‑brain, distributed locking strategies, expiration and eviction policies, high‑availability architectures, and rate‑limiting techniques.
This article explains Bloom filters, their core principles, typical use cases like cache penetration and large‑scale membership testing, and demonstrates practical Java implementations using Guava and Redis, including code examples, performance analysis, and discussion of their advantages and limitations.
This article explains three Redis-based approaches—using Hashes, Bitsets, and the HyperLogLog probabilistic algorithm—to count daily website visits, detailing command usage, advantages, disadvantages, and implementation considerations for high‑traffic sites, including handling logged‑in and anonymous users, memory consumption, and accuracy trade‑offs.
lock4j-spring-boot-starter is a Spring Boot distributed lock library that provides simple yet powerful locking capabilities with support for Redisson, RedisTemplate, and Zookeeper, and the 2.1.0 release adds global configuration, executor enhancements, default priority ordering, and both declarative and programmatic usage options.
This article explains how Spring Boot integrates Redis, reveals a common pitfall where different RedisTemplate beans cause null reads despite existing data, and shows how to diagnose and fix the issue by aligning bean types and injection annotations.
This guide shows how to create a custom Scrapy command to launch every spider at once, separate each spider's settings for better modularity, and resolve video download problems by adjusting request headers and handling file saving correctly.
This article analyzes a P0 flash‑sale incident where Redis distributed locks expired and non‑atomic stock checks caused a 100‑bottle over‑sell, then presents safer lock implementations, atomic stock decrement, and architectural improvements to avoid similar failures.
This guide walks through Redis’s eight core data structures—String, List, Set, Hash, Sorted Set, Geospatial, HyperLogLog, and Bitmap—detailing their commands, practical usage scenarios, and example interactions to help developers ace interview questions and optimize NoSQL solutions.
Short URLs are popular in SMS and social media because they save characters, look tidy, enable analytics, and hide parameters; this article explains their benefits, the basic redirect workflow, and provides a detailed backend design—including storage choices, high‑concurrency strategies, distributed ID generation, and a Java‑Redis implementation.
This article analyzes a real‑world flash‑sale incident where a Redis distributed lock expired under high load, causing a 100‑bottle product to be oversold, and presents safer lock implementations, atomic stock checks, and performance‑oriented redesigns to prevent such failures.
This article reviews five widely used cache read/write strategies—including simple write‑DB‑then‑cache, Cache‑Aside, Write/Read‑Through, Write‑Back, and LRU eviction—explaining their workflows, advantages, disadvantages, and suitability for different production scenarios.
This article explains how to build a high‑concurrency ticket‑spike system by analyzing 12306's extreme load, introducing multi‑layer load balancing (OSPF, LVS, Nginx), comparing stock‑deduction strategies, and presenting a Go prototype that uses in‑memory stock, Redis centralized inventory, and weighted Nginx routing to achieve scalable, fault‑tolerant performance.
This article explores the architecture and implementation of a high‑concurrency ticket‑spike system, covering distributed load‑balancing, Nginx weighted round‑robin configuration, Go‑based local and remote stock deduction with Redis, performance testing, and strategies to avoid overselling and underselling.
This article details a complete end‑to‑end high‑concurrency tuning process for a Java SSM monolithic e‑commerce system, covering problem identification, root‑cause analysis, a series of JVM, Tomcat, Redis and JDBC optimizations, horizontal scaling, code refactoring, and the resulting stability improvements.
This article explores various techniques to achieve API idempotency in high‑concurrency environments, including token mechanisms, deduplication tables, Redis SETNX keys, state‑machine checks, and both optimistic and pessimistic locking, highlighting their workflows, advantages, and trade‑offs.
This article explains why Redis creates 16 logical databases by default, how to configure their number, the correct way to treat these databases as namespaces rather than separate stores, and why multiple databases are not supported in Redis Cluster mode.
This article explores the architecture and implementation of a high‑concurrency ticket‑spike system inspired by China’s 12306 platform, covering load‑balancing strategies, Nginx weighted round‑robin, local and remote inventory deduction, Go concurrency patterns, Redis atomic operations, and performance testing results.
This article explains how to design a Redis high‑availability solution using the official Sentinel, covering its core features, configuration steps, three methods for receiving failover notifications, overall architecture diagrams, and practical recommendations for deployment and scaling.
This article explains why Redis memory usage stays high after deleting keys, describes memory fragmentation causes, shows how to detect fragmentation with INFO memory and mem_fragmentation_ratio, and provides practical steps and configuration options to clean and prevent fragmentation.
This comprehensive guide covers essential Redis interview topics, including persistence mechanisms (RDB and AOF), cache challenges such as avalanche, penetration and pre‑warming, data types and their use cases, internal structures, eviction policies, single‑thread performance, clustering solutions, distributed locking, transactions, and best practices for high‑traffic environments.
The article analyzes the extreme‑traffic challenges of China’s 12306 ticket‑spike service, presents a layered load‑balancing architecture using OSPF, LVS, and Nginx weighted round‑robin, and demonstrates a Go‑based prototype that combines local in‑memory stock deduction with Redis‑backed global stock control to achieve stable, high‑throughput ticket purchasing without overselling.
This article explains Redis's event-driven architecture, detailing file and time events, their processing flow, and why Redis 6.0 introduced multithreading to improve network I/O while keeping command execution single‑threaded.
This article provides a step‑by‑step guide for manually building a six‑node Redis cluster on macOS, detailing environment setup, configuration changes, node startup, slot allocation, and converting master nodes to slaves, with screenshots and command examples.
This article explains how to use Redis sets, sorted sets, bitmaps, and HyperLogLog for various aggregation, sorting, binary state, and cardinality statistics, providing concrete command examples, design patterns, and performance considerations for large‑scale applications.
This guide walks you through downloading, extracting, compiling, and installing Redis from source on Ubuntu, configuring its files and startup scripts, securing the service, enabling automatic boot start, and performing data migration with detailed commands and examples.
This article explains the mechanisms of Redis master‑slave data synchronization—including full and partial resynchronization—details the internal workings of Redis clustering, slot assignment, automatic node detection, and failover recovery, and provides practical insights for building reliable Redis deployments.
Redis, an in‑memory C‑language database, offers ultra‑fast read/write speeds, rich data structures, persistence, clustering, and multi‑threaded I/O, making it ideal for distributed caching, locks, queues, and more; this guide explains its fundamentals, comparisons with Memcached, data types, eviction policies, and operational best practices.
This article introduces Redis's eight fundamental data types—String, List, Set, Hash, Sorted Set, Geospatial, HyperLogLog, and Bitmap—explaining their characteristics, typical use‑cases, and providing concrete command‑line examples that demonstrate creation, manipulation, and querying of each type.
This article outlines five practical methods for synchronizing MySQL data to external systems such as Elasticsearch, Redis, and message queues, covering business‑layer hooks, middleware integration, scheduled tasks using updated_at, binlog parsing with ROW format, and handling mixed or statement binlog formats, plus open‑source tools.
This article explains the concept and common use cases of delayed messages and compares five practical implementation methods—using Redis sorted sets, RabbitMQ delayed‑message exchange plugin, ActiveMQ scheduled messages, RocketMQ fixed delay levels, and a custom RocketMQ solution—detailing their workflows, advantages, and drawbacks.
This article provides a comprehensive guide to Redis for interview preparation, covering persistence mechanisms, common caching challenges such as avalanche and penetration, data types and their use cases, internal structures, expiration policies, single‑threaded performance, clustering options, distributed locking, and best‑practice solutions.
This guide reviews Redis's eight fundamental data types—String, List, Set, Hash, Sorted Set, Geospatial, HyperLogLog, and Bitmap—explaining their commands, usage scenarios, and practical examples to help developers and interviewees master this popular NoSQL database.
This article explains how to prevent and gracefully handle duplicate requests on the server side by using unique request IDs with Redis, generating MD5 digests of request parameters, and provides a reusable Java helper class with code examples and testing logs.
This article explains Redis's cache expiration policies—including timed, periodic, and lazy eviction—details the internal structure and parsing of RDB files, and describes the AOF persistence mechanism with its write‑ahead logging, synchronization options, and rewrite process, providing a comprehensive view of Redis data durability.
This article explains how to use Zabbix Agent2 to monitor Redis, covering the plugin's architecture, configuration priority, methods for retrieving INFO, CONFIG, health status, and slow‑query logs, as well as practical steps to set up the Redis template in Zabbix.
This article walks through a practical approach for front‑end engineers to cut down a sluggish legacy API from over three seconds to under a second by adding a Node.js proxy layer that leverages GraphQL field selection, Redis caching, and a scheduled cache refresh.
This article introduces Redis as a high‑performance, in‑memory NoSQL database, explains why learning it is valuable, provides step‑by‑step installation instructions, and presents essential commands for keys, strings, lists, sets, sorted sets, and hashes with practical code examples.
This article explains Redis's two persistence mechanisms—AOF (Append Only File) and RDB (snapshot)—detailing their concepts, write‑back strategies, rewrite process, performance trade‑offs, snapshot handling, copy‑on‑write technique, incremental snapshots, and the benefits of combining both approaches.
This article narrates how Redis, personified as a character, synchronizes data between master and slave nodes through command propagation, adopts improved sync strategies, and uses Sentinel's INFO and PING checks to detect failures and automatically trigger failover, illustrating a practical high‑availability cache service.
This article provides a comprehensive guide to Redis persistence mechanisms, detailing how RDB snapshots and AOF logs work, how to configure and use them, their advantages and drawbacks, and how to choose the right approach for reliable data storage.
This article details Xiaomi's migration of tens of thousands of Redis instances from physical servers to Kubernetes, explaining the motivations for containerization, the deployment architecture with StatefulSets and a custom Redis Proxy, performance comparisons of proxy options, operational challenges, and the resulting benefits in resource utilization, automation, and service stability.
This page continuously gathers and organizes over 200 Java backend interview Q&A articles, covering topics such as Spring, Redis, MySQL, concurrency, design patterns, and system design, providing a valuable resource for candidates to review before interviews.
This tutorial explains how to install Redis on Linux (including source compilation and Docker), set it up as a daemon, install the PHP Redis PECL extension, configure Composer, install ThinkPHP5, and run a simple PHP script that stores and retrieves a value from Redis.
This article explains why using the KEYS command on massive Redis datasets can cause service blockage, analyzes the underlying O(n) traversal cost, and demonstrates how the incremental SCAN command with cursor, MATCH, and COUNT options provides a non‑blocking alternative for efficiently iterating keys.
This article examines common techniques for implementing a user check‑in function in web and mobile applications, comparing a straightforward MySQL table solution with a Redis bitmap approach, detailing the data structures, code examples, workflow, and the advantages and disadvantages of each method.
This article explores the architecture and implementation of a high‑concurrency ticket‑spike system, covering load‑balancing strategies, Nginx weighted round‑robin configuration, local stock deduction in Go, remote stock control with Redis Lua scripts, and performance testing results.
The article explains how a single‑machine Java lock can cause inventory oversell in a distributed e‑commerce system, introduces the concept of a global distributed lock, and compares practical implementations using Redis (including RedLock and Redisson) and Zookeeper (with Curator), highlighting their trade‑offs and selection guidelines.
This guide walks through checking your PHP configuration, downloading the appropriate Redis extension, installing it, updating php.ini, verifying the installation, starting the Redis service, and shows the core template and PHP server code needed to implement a historical search queue using Redis.
This article explains why Redis uses a custom SDS string structure instead of native C strings, describes the SDS layout, expansion rules, redisObject metadata, and the three string encodings (int, embstr, raw) that optimize performance and memory usage.
This guide explains seven critical Linux operating‑system settings—memory overcommit, swappiness, Transparent Huge Pages, OOM killer, NTP synchronization, ulimit, and TCP backlog—that together ensure Redis runs reliably and at peak speed.
This guide demonstrates how to set up a Redis multi-database singleton wrapper in a ThinkPHP project, covering prerequisite installation, configuration of connection parameters, creation of a custom Redis class with static instance management, and example usage of Redis commands across different databases.
This article explains the cache breakdown problem, introduces Laravel 7's built‑in RedisLock class, details its constructor parameters, and provides a complete code example demonstrating how to acquire and release a Redis lock to safely populate and update cached data.
