This article presents a simulated interview that explains Redis's evolution from single‑threaded to optional multithreading, its in‑memory performance advantages, persistence options (AOF, RDB, hybrid), high‑availability architectures, and the consistent‑hashing based slot allocation used by Redis Cluster.
Undermoon migrates Redis Cluster slots quickly and simply by orchestrating SCAN, DUMP, PTTL, RESTORE and DEL commands through migrating and importing proxies, balancing CPU load, handling delete‑prone keys, and achieving sub‑minute migration of 1 GB with throughput recovery.
This tutorial explains how to quickly set up a Spring Cloud Gateway service, configure static and Nacos‑driven dynamic routes, and implement a Redis‑backed authentication filter that validates tokens, refreshes expiration, and forwards user information to downstream services.
This article details the three‑stage evolution of an e‑commerce recommendation framework—V1.0’s simple strategy‑factory design, V2.0’s vertical business split, and V3.0’s configurable pipeline with dynamic server‑client configuration, addressing scalability, isolation, and AB‑testing challenges.
This article shares a detailed account of a backend engineer's multi‑stage interview process at Huanju (formerly YY), covering personal background, common Java and system design questions, database and caching strategies, distributed lock handling, and reflections on preparation and outcomes.
This article surveys various delayed queue implementations—including Kafka, RocketMQ, Redis (Redisson), and Netty’s HashedWheelTimer—examining their design principles, advantages, drawbacks, and integration strategies, and proposes a unified micro‑service architecture leveraging Kafka topics, Redis ZSETs, and thread‑pool optimizations for reliable message scheduling.
This article explains how to design and implement a high‑concurrency ticket‑seckill system by analyzing the 12306 architecture, introducing multi‑layer load balancing, demonstrating Nginx weighted round‑robin configuration, and providing Go and Redis code to achieve stable, low‑latency ticket purchasing under massive simultaneous requests.
This step‑by‑step tutorial shows how to build Undermoon from source, deploy a memory broker, coordinator, two server proxies and four Redis nodes on a single machine, register them via JSON APIs, create a named cluster, and verify its operation with redis‑cli.
The article explains why service rate limiting is essential for high‑concurrency systems, compares it with service degradation, describes common algorithms such as counter, leaky bucket and token bucket, and shows how to implement distributed rate limiting using Redis.
This guide walks through setting up an Undermoon Redis cluster using Docker Compose, covering prerequisites, building images, registering proxies, creating and scaling the cluster, and demonstrating automatic failover with concrete command‑line examples.
This guide walks through building Helm charts, deploying the Undermoon operator, creating and scaling a Redis Cluster on Kubernetes, and configuring the undermoon‑scheduler to ensure master‑replica placement across nodes, with detailed commands and parameter explanations.
This article shares a step‑by‑step account of a candidate's three‑round ByteDance interview, covering background, technical questions on Java, JVM, Redis, MySQL, Kafka, and algorithm challenges, along with personal reflections on pacing, preparation, and why concise answers matter.
This tutorial explains Redis Bitmaps, covering their underlying concept, core commands such as SETBIT, GETBIT, BITCOUNT, BITOP, BITPOS, BITFIELD, and demonstrates practical uses like online‑status tracking, daily active‑user counting, Bloom filters, marketing segmentation, collaborative drawing, and handling non‑sequential IDs.
This article explains why Redis achieves high query performance by leveraging in‑memory storage, specialized data structures such as SDS, linked lists, dictionaries, ziplists and skiplists, a single‑threaded event loop with I/O multiplexing, and various optimization techniques that avoid common bottlenecks.
Learn how to leverage OpenResty and Lua to replace traditional Tomcat‑Redis pipelines with direct Nginx caching, compress responses, schedule periodic updates, and configure dynamic URL caching, dramatically reducing latency and improving concurrency for high‑traffic web services.
Undermoon is an open‑source system that implements a self‑managing Redis cluster using the Redis Cluster protocol, offering horizontal scalability, high availability, HTTP‑API management, automatic master‑replica failover, and rapid expansion, with its architecture detailed across metadata storage, coordinator, storage cluster, and chunk components.
This article details how the Beike instant‑messaging system was analyzed, bottlenecks identified, and a series of backend optimizations—including business isolation, increased concurrency, computation reduction, and Redis connection‑pool redesign—were applied to boost 300‑person group‑chat throughput from 15 QPS to over 320 QPS, achieving more than a twenty‑fold performance gain.
This article explains how to improve large file upload experience by using instant (MD5‑based) upload, chunked (slice) upload, and breakpoint‑resume upload, detailing the Redis‑based state management and providing Java backend implementations with RandomAccessFile and MappedByteBuffer.
This article explains why Redis needs high availability, defines failure scenarios, compares common HA solutions, and walks through four deployment patterns—from a single instance to a three‑Sentinel architecture—highlighting their trade‑offs and practical implementation details.
This article explains the concept of delayed queues, outlines typical use cases, compares implementation options, and provides a complete Java Spring Boot example that uses Redis Zset to create, manage, and execute delayed tasks with accompanying code snippets and test results.
The article explains how Undermoon’s Chunk, composed of two proxies and four Redis nodes spread across two machines, forms the core building block for a balanced Redis cluster topology and load‑balancing strategy, detailing its node layout, failover behavior, and simple allocation algorithm.
This article explains the design, implementation, and optimization of a Redis‑based delay queue using SpringBoot, Redisson, and distributed locks, covering use cases, architecture, data structures, job lifecycle, core code snippets, and future improvements for reliability and scalability.
The article explains how the Rust‑based Undermoon project implements the Redis Cluster Protocol using a server‑side proxy, detailing the protocol’s responsibilities, the advantages of this approach over traditional proxies, and providing step‑by‑step commands and code examples for deployment.
This article explains why Redis needs high availability, defines failure scenarios, compares several HA architectures—including single‑instance, master‑slave with one or multiple Sentinel processes, and a three‑node solution with a virtual IP—and provides practical guidance for building a reliable Redis service.
This article explains the concept of distributed locks, compares three implementation methods—database unique indexes, Redis (using SETNX), and Zookeeper—provides detailed SQL table design and Java code examples for acquiring and releasing locks, and discusses reentrancy, lock release timing, and single‑point failure considerations.
This guide walks through deploying a Redis cluster on Kubernetes, covering the challenges of stateful workloads, the use of StatefulSets and Headless Services, configuration of persistence, and step‑by‑step commands to create, initialize, and expose the cluster.
This tutorial walks through creating a Spring Boot lottery application that caches activity, prize, and record data in Redis, covering project setup, Maven dependencies, YML configuration, MyBatis‑Plus code generation, Redis key management, lottery API, event‑driven data loading, stock handling, and asynchronous record saving.
This guide shows how to use the Bitnami Helm chart to quickly deploy a Redis Cluster in a Kubernetes "redis" namespace, customize its values.yaml, retrieve the auto‑generated password, and add RedisInsight with a persistent volume for web‑based management.
This article presents a step‑by‑step guide to building a Spring Boot lottery application that leverages MyBatis‑Plus and Redis for caching activity, prize, and record data, covering project setup, dependencies, configuration, code generation, Redis integration, lottery logic, and stock management.
This article compares the Java Redis clients Jedis, Redisson, and Lettuce, explains their distinct features and thread‑safety models, and provides detailed Spring Boot configuration and code examples for using RedisTemplate, RedissonClient, and annotation‑based caching to implement distributed locks, hash operations, and cache management.
This guide explains how to implement fast, reliable large file uploads in Java using chunked (slice) uploads, instant (秒传) transfer via MD5 deduplication, and breakpoint resume, detailing Redis state tracking, RandomAccessFile and MappedByteBuffer server‑side code, and practical deployment considerations.
This article explains the challenges of at‑least‑once delivery in distributed message middleware like RocketMQ, examines simple and concurrent deduplication techniques, and presents both transaction‑based and non‑transactional exactly‑once solutions using database tables or Redis, along with practical Java code examples.
This article explains Redis’s original single‑threaded event‑driven architecture, its performance bottlenecks, and how versions 4.0 and 6.0 introduced Lazy Free and multithreaded I/O mechanisms—including asynchronous key deletion, background freeing, and I/O thread pools—to improve scalability while outlining their implementation details, limitations, and comparisons with Tair.
Vivo’s self‑built database and storage platform evolved from a fragmented 2018 system into a two‑layer DaaS solution offering unified management, automated security, high availability, and cost‑effective scaling across MySQL, Redis, TiDB, object storage, and future autonomous services within a hybrid‑cloud architecture.
This article explains how to implement fast (MD5‑based) upload, chunked upload, and resumable (break‑point) upload for large files in Java, detailing the Redis‑based status tracking, server‑side file handling with RandomAccessFile or MappedByteBuffer, and the required front‑end and back‑end coordination.
This article outlines the first, second, and HR interview rounds for a CCBank online position, detailing over thirty technical and behavioral questions covering Elasticsearch, Redis, Spring Cloud, JVM, data structures, performance optimization, and candidate queries, followed by a concise summary.
This article explains how to select Redis data structures such as Bitmap, HyperLogLog, Set, List, Sorted Set, and Hash to efficiently handle massive statistical scenarios like user login status, UV counting, ranking, and set aggregation, while providing concrete command examples and best‑practice recommendations.
This article examines common delayed (scheduled) message implementations in distributed systems, comparing external storage approaches using databases, RocksDB, and Redis, as well as built-in solutions in open-source MQs like RocketMQ, Pulsar, and QMQ, and discusses their advantages, drawbacks, and design considerations.
This article explains why distributed locks are needed beyond Java's JVM‑level locks, compares three common implementation approaches—database unique indexes, Redis SETNX, and Zookeeper ephemeral sequential nodes—and provides concrete SQL and Java code examples with analysis of re‑entrancy, release timing, and single‑point risks.
This article explains the business scenarios that require delayed processing, compares several existing delayed‑queue solutions, and details a Redis‑backed delayed‑queue design—including its data structures, message format, multi‑node deployment, and runtime workflow—providing practical guidance for building scalable backend systems.
This article demonstrates how to use Redis key‑expiration notifications together with Spring Boot to automatically close orders that remain unpaid after a configurable timeout, eliminating inefficient polling and providing a clean backend solution for order lifecycle management.
This article introduces essential Redis operational tools, covering the INFO command for monitoring, Prometheus‑based redis‑exporter visualization, the Redis‑shake data migration utility, Redis‑full‑check consistency verification, and the CacheCloud platform for comprehensive cluster management.
This article examines whether Redis can serve as a reliable message queue by exploring its List, Pub/Sub, and Stream data structures, detailing their usage, advantages, drawbacks, and how they compare to dedicated queue middleware.
This article explains how to implement a distributed lock using Redis by setting a unique key-value pair, handling expiration, addressing lock timeout issues, and leveraging Redisson's watchdog mechanism with automatic renewal, including detailed code examples for tryLock, subscription, and renewal processes.
The article details a week‑long investigation of unresponsive APIs in a sandbox environment, tracing the root cause to Redis connection pool blocking in a Spring Boot service, and presents step‑by‑step debugging, code analysis, configuration fixes, and best‑practice recommendations for proper Redis usage.
The article explains a typical payment‑timeout scenario and compares four backend solutions—database polling, Java DelayQueue, Redis sorted set, and RabbitMQ TTL with dead‑letter exchange—detailing their mechanisms, advantages, and drawbacks for implementing delayed task cancellation.
This article explains how to implement a Role‑Based Access Control (RBAC) permission model in Spring Cloud Gateway, covering the design, loading URL‑role mappings into Redis, customizing UserDetailsService, and integrating OAuth2.0 with code examples and database schema.
This article explains how to protect a Spring Boot API from traffic spikes by applying common rate‑limiting algorithms, configuring Redis for distributed throttling, writing Lua scripts for atomic counters, and integrating a custom @Limit annotation with AOP to enforce limits across a cluster.
Redis distributed locks rely on a key-value marker with unique client IDs, expiration times, and careful release checks; the article explores lock timeout challenges, automatic renewal via watchdog mechanisms, Redisson's tryLock implementation, Lua‑based renewal scripts, and best practices to avoid deadlocks and resource waste.
This article explains how to implement a distributed lock using Redis, discusses challenges with lock expiration, describes automatic renewal techniques such as watchdog mechanisms, and provides detailed Java code examples of Redisson's tryLock and renewal processes.
The article explains skip list fundamentals, shows how probabilistic multi‑level indexing yields O(log n) search and O(n) space, provides a complete Go implementation with insertion, deletion and search functions, compares Redis’s enhanced skip list used in sorted sets, and answers common design questions.
This article explains the concept of delayed tasks, compares them with scheduled tasks, and presents five implementation approaches—database polling, JDK DelayQueue, time‑wheel algorithm, Redis sorted sets, and message‑queue based delay queues—detailing their code, advantages, and drawbacks.
In distributed e‑commerce systems, achieving Redis cache consistency requires invalidating stale entries via reliable DB change detection (e.g., binlog listeners) and optionally using versioned writes that only update when newer, combined with safeguards like TTLs, double deletes, and business‑specific designs to mitigate race conditions and ensure eventual consistency.
This tutorial explains how to achieve automatic API idempotency in Spring Boot by leveraging Redis for token storage, creating a custom @AutoIdempotent annotation, configuring an interceptor to validate tokens, and providing complete code examples and test cases to prevent duplicate operations.
The article details a step‑by‑step investigation of a Spring‑based backend where API requests hung due to Redis connection pool misconfiguration, showing how thread dumps, jstack, and Arthas were used to pinpoint blocking in Jedis pool acquisition, and provides corrected configuration and proper connection handling recommendations.
This article explains why simple byte‑stream uploads fail for large files and introduces three robust solutions—instant (hash‑based) upload, chunked (slice) upload, and resumable upload—detailing their core logic, Redis tracking, and Java implementations using RandomAccessFile and MappedByteBuffer, plus practical code snippets.
This guide walks you through installing JumpServer—a bastion host solution that adds permission control, session monitoring, and audit logging to remote server access—by setting up MariaDB and Redis, configuring Docker, generating secret keys, running the JumpServer container, and configuring users, groups, assets, and permissions.
Learn how to deploy a Redis cluster on Kubernetes by using a StatefulSet with a headless Service, configuring persistent storage, creating ConfigMaps, initializing the cluster with redis-cli, and exposing it via a regular Service, complete with step‑by‑step commands and YAML examples.
This article explains how to leverage OpenResty and Lua scripts to integrate Nginx with Redis for direct caching, compression, timed updates, request forwarding, and configurable URL management, thereby improving concurrency, reducing latency, and enhancing the resilience of backend web services.
This tutorial walks through installing MariaDB and Redis on a backend node, configuring Docker on a separate host, pulling and running the JumpServer container, and then setting up users, assets, and permissions so that operations teams can securely manage internal servers via a bastion host.
This guide explains how to improve large file upload performance by using instant (hash‑based) uploads, chunked (slice) uploads, and breakpoint‑resume strategies, detailing the underlying Redis state tracking, server‑side Java implementations with RandomAccessFile and MappedByteBuffer, and practical deployment considerations.
After a week of API timeouts in an internal sandbox, we traced the issue to Redis connection pool deadlocks caused by improper Jedis resource handling in Spring, revealing how missing maxWaitMillis settings and unreleased connections can freeze all HTTP threads.
This article explains how to invalidate JWT tokens during password changes, permission updates, or logout by using a Redis-backed blacklist approach in Spring Cloud Gateway, detailing the extraction of the token's jti, gateway filtering, downstream modifications, and a logout endpoint implementation.
This article explains how to implement a Redis distributed lock in Java using Jedis, covering Maven setup, lock creation with setNX, safe lock release via Lua scripts, and a realistic 100,000‑user flash‑sale simulation to demonstrate concurrency control.
This article explains how to implement a Redis-based distributed lock, discusses the challenges of lock expiration, introduces automatic renewal strategies such as watchdogs, and provides detailed Redisson tryLock and renewal code examples for reliable concurrency control.
The article explains how Redis, originally a single‑threaded in‑memory cache, introduces Lazy Free in version 4.0 and multi‑threaded I/O in version 6.0 to mitigate blocking during large key deletions, describes the underlying event‑driven architecture, shows relevant source code, and discusses the benefits and constraints of these mechanisms.
Spring Boot 2.6.0 introduces several important changes such as default prohibition of circular dependencies, custom sanitizing functions, automatic Redis connection‑pool activation, moved reactive session properties, Maven build‑info exclusions, WebTestClient support for MVC testing, and Log4j2 composite configuration options.
This article explains how to implement fixed‑time scheduled tasks on a single machine using Timer and ScheduledThreadPoolExecutor, how to build a custom Redis‑based distributed scheduler with distributed locks, and compares several third‑party frameworks such as Quartz, TBSchedule, Elastic‑Job and Sature for distributed task execution.
This article explains how Redis implements its Sorted‑Set data type by starting from a basic ordered singly linked list, analyzing its insertion and query complexities, introducing the skiplist structure, deriving its O(log N) performance, and detailing the underlying C source code for creation, insertion, lookup, and deletion.
This article explains the difference between synchronous and asynchronous microservice communication, outlines the benefits of async messaging, and compares three popular message brokers—RabbitMQ, Kafka, and Redis—based on scale, persistence, and consumer patterns, offering guidance on selecting the right broker for various use cases.
This article introduces essential Redis operational tools, covering the INFO command for real‑time monitoring, Prometheus‑based exporters, data migration utilities like Redis‑shake, consistency checking with Redis‑full‑check, and cluster management via CacheCloud, while offering practical usage tips.
This article explains how Redis, originally a single‑threaded in‑memory cache, introduced Lazy Free and multi‑threaded I/O to eliminate blocking during large key deletions, improve QPS, and lay the groundwork for future multithreading strategies.
This tutorial explains how to use the WeChat material management API, Redis caching, and Node.js middleware to obtain access tokens, upload and replace images, inline CSS, and finally create draft articles for automatic publishing on a WeChat public account.
This article examines the core challenges of flash‑sale (秒杀) systems—such as overselling, extreme concurrency, bot traffic, and database strain—and presents a comprehensive backend design that includes dedicated databases, dynamic URLs, static pages, Redis clustering, Nginx load balancing, SQL optimization, rate‑limiting, asynchronous order queues, and service degradation strategies.
This article explores how caching accelerates read/write performance and reduces backend load, analyzes its benefits and costs, and presents practical strategies for cache updates, granularity control, penetration, avalanche, and hot‑key issues with concrete examples and diagrams.
The article explains how Redis read/write separation works, compares star and chain replication architectures, and highlights the benefits of transparent compatibility, high availability, and improved performance for read‑heavy, write‑light workloads.
This article explains three Redis‑based rate‑limiting strategies—using SETNX, sorted‑set (ZSet) sliding windows, and a token‑bucket algorithm with List—provides Java code examples for each method, discusses their advantages and drawbacks, and shows how to integrate them into backend services.
This article examines the benefits, costs, and design patterns of caching—including update policies, granularity control, penetration, bottom‑hole, avalanche, and hot‑key issues—while offering concrete optimization techniques and practical recommendations for building robust Redis‑MySQL cache layers.
This article compares the three popular Java Redis clients—Jedis, Redisson, and Lettuce—detailing their differences in threading, I/O, and feature sets, and provides comprehensive Spring Boot configuration and code examples for using StringRedisTemplate, RedissonClient, and Spring Cache annotations to implement caching and distributed locks.
This tutorial explains Docker image layers, demonstrates step‑by‑step labs that build and progressively slim a Redis image using smaller base images, command chaining, compression tools, and scratch‑based builds, and shows how Go binaries can produce ultra‑small containers.
Learn how to deploy a Redis cluster on Kubernetes using a StatefulSet and Headless Service, covering problem analysis, key concepts, configuration steps, initialization with redis-cli, and creating services for access, all without persistent volumes for simplicity.
This guide explains Redis AOF persistence settings, including default options, the three synchronization strategies (no, always, everysec), and practical recommendations such as enabling AOF on slaves for critical data while keeping masters free of persistence work.
This article explains how caching improves application performance and reduces backend load, and it details practical optimization methods such as benefit‑cost analysis, update policies, granularity control, penetration protection, bottomless‑hole mitigation, avalanche prevention, and hot‑key rebuild strategies, primarily using Redis.
This article explains how to use Redis as a distributed lock via Jedis in Java, covering lock creation with SETNX/NX/PX, lock deletion with Lua scripts, and a complete 100,000‑user concurrency simulation that demonstrates inventory control and lock management for flash‑sale scenarios.
Learn how to implement distributed locks in Spring-based applications using Spring Integration, covering Redlock, Apache Curator alternatives, and detailed step-by-step examples for Redis and Zookeeper backends, including configuration, code snippets, testing procedures, and troubleshooting tips for reliable lock management.
This article walks through implementing a complex e‑commerce search API, starting with a monolithic SQL query, then refactoring it into multiple indexed queries, and finally accelerating it with Redis set and sorted‑set operations, including pagination and transaction optimizations.
This article provides a thorough introduction to Redis, covering its core data structures and common commands, persistence options (RDB and AOF), memory‑management and eviction policies, pipelining, transactions and Lua scripting, performance optimization techniques, replication, Sentinel high‑availability, cluster sharding, and a comparison of popular Java clients.
With hardware costs dropping, many default to Redis for caching, but it isn’t always optimal; this article examines EhCache—a pure‑Java, in‑process cache—covering its architecture, eviction policies, API and XML configurations, and step‑by‑step Spring Boot integration, helping you decide when to prefer it.
This guide explains how to build a dynamic IP blacklist using Nginx, Lua scripts, and Redis to block malicious or unwanted requests at the server level, covering architecture choices, installation steps, configuration details, and the benefits of a lightweight, shared, and easily updatable solution.
This tutorial walks through downloading, compiling, installing, configuring, and setting up Redis 6.2.6 as a systemd service on a Linux server, including key configuration changes and commands to start the server and enable it at boot.
This article explains the need for globally unique, high‑performance, and easy‑to‑integrate distributed IDs, outlines their essential characteristics, and compares nine common generation approaches—including UUID, database auto‑increment, segment mode, Redis, Snowflake, Baidu uid‑generator, Meituan Leaf, and Didi TinyID—detailing each method’s advantages and drawbacks.
This article examines the limitations of Redis master‑slave replication, explains how Redis Sentinel addresses those issues with monitoring, notification, and automatic failover, and provides detailed configuration commands, discovery mechanisms, and step‑by‑step failover procedures for building a highly available Redis deployment.
This article explains how Redis implements its Sorted‑Set using a skiplist, starting with the basics of a singly linked list, analyzing insertion and query complexities, deriving the skiplist structure and its O(log N) performance, and comparing it with hash tables, balanced trees, and B‑trees.
This article explains how to implement a Redis distributed lock using Jedis in Java, covering lock creation with SETNX, expiration handling, lock deletion via Lua scripts, and a high-concurrency flash‑sale simulation with 100,000 parallel users.
This article presents thirteen practical Redis performance optimization rules, covering avoidance of slow commands, proper key expiration handling, data structure selection, persistence strategies, hardware considerations, pipelining, client optimization, and clustering to maximize throughput and minimize latency in high‑volume deployments.
This article thoroughly examines how Redis distributed locks work, the pitfalls of simple SETNX‑based locks such as deadlocks and premature expiration, presents robust solutions using expiration, unique identifiers, Lua scripts, discusses the Redlock algorithm and its controversy, compares Zookeeper locks, and offers practical guidance for safe lock usage.
This comprehensive guide explains the principles, pitfalls, and best practices of implementing Redis distributed locks, covering basic SETNX usage, lock timeout handling, re‑entrant locks, Redlock algorithm debates, and practical Redisson integration with Spring Boot.
This article explains Redis's high‑performance I/O architecture by tracing the evolution from blocking, non‑blocking, and multiplexed network models to various Reactor‑based thread designs, illustrating each model with Java pseudo‑code and diagrams to clarify why Redis adopts a single‑threaded Reactor with optional multi‑threaded I/O extensions.
Django 4.0 has been officially released, bringing built‑in Redis caching, enhanced form customization, new password hashing, default zoneinfo support, upgraded jQuery, PostgreSQL improvements, and a test runner shuffle option, with a simple pip installation command.
This article explains why a single‑instance Redis can cause outages, introduces the master‑slave architecture, details the full and incremental synchronization processes, shows how to configure replication, addresses multi‑slave scaling, network interruptions, and automatic failover with Sentinel.
