Redis can become a bottleneck when a hot key concentrates traffic on a single shard; this article explains how to split such hot keys into multiple sub‑keys, distribute them across cluster nodes using CRC16 slot mapping, and implement the approach in high‑concurrency scenarios like coupon grabs or real‑time leaderboards.
This article introduces Bloom filters and Cuckoo filters, explains their probabilistic nature, false‑positive behavior, space‑time trade‑offs, provides Go and Java implementation examples, and discusses practical use cases such as Redis extensions and high‑traffic e‑commerce scenarios.
This article compiles an extensive Python reference covering Python 2 vs 3 differences, essential and advanced libraries, concurrency models, language internals, testing techniques, design patterns, data structures, algorithms, networking basics, MySQL and Redis insights, Linux I/O models, and performance‑optimization strategies, all illustrated with practical code snippets.
The article recounts a recent Hikvision interview, outlining campus salary ranges and providing a technical Q&A that explains Spring Boot’s startup sequence, Spring MVC request handling, MySQL index structures, creation rules, and performance diagnostics, as well as Redis’s in‑memory, single‑threaded architecture and optional I/O threading.
This article explains Redis 4.0's LFU‑based hot key detection mechanism, including its probabilistic counter algorithm, decay factor, and configuration options, and then describes Redis 6.0 client‑side caching with tracking, default and broadcast modes, and related protocol considerations.
This article walks through the complete process of implementing WeChat QR code login using a Java Spring Boot backend, covering prerequisite configuration, Maven dependencies, configuration classes, QR code generation, callback handling, session storage in Redis, and frontend integration.
This guide walks through installing software on CentOS using source tarballs, RPM packages, and yum, covering terminology, step‑by‑step commands, and practical examples with Redis, RabbitMQ, and Nginx.
This article presents a comprehensive engineering guide for importing one billion 1 KB unstructured log records stored in HDFS or S3 into MySQL, covering data sizing, B‑tree limits, batch insertion strategies, storage‑engine choices, sharding, file‑reading techniques, concurrency control, and reliable task coordination using Redis, Redisson, and Zookeeper.
The article presents a Redis‑based distributed ID generator for Spring Boot 3.0 that uses an atomic INCR on a Redis string to produce compact, monotonic, globally unique numeric identifiers, synchronizes the maximum value with MySQL on startup, and offers high performance, availability, and low storage overhead.
This article explains how to enable cross‑node WebSocket communication in a distributed Spring application by using a message queue (Redis or Kafka) to broadcast messages, tracking user connections with Redis, and providing a complete step‑by‑step implementation with code samples and configuration details.
Learn how to deploy Alibaba Cloud Tair (Redis) with ECS and RDS, verify caching functionality, conduct Locust performance tests, and clean up resources, all through a step‑by‑step guide that demonstrates significant latency reduction and database load mitigation.
This article recounts five successive performance optimizations applied to a SpringBoot‑Thymeleaf category‑tree API—adding Redis caching, scheduled async refresh jobs, local Caffeine memory cache, gzip compression via Nginx, and Redis data slimming—transforming query latency and scaling QPS from around 100 to over 500.
This article explains three backend strategies—session‑cookie, token, and JWT—to ensure an account can only be active on one device at a time, detailing the workflow, data structures, and Redis integration needed to implement forced logout across multiple endpoints.
Redis’s evolution from linked lists to ziplist, quicklist, and the newer listpack is examined in depth, highlighting their structures, memory‑performance trade‑offs, operational details, and practical guidance for Java developers on choosing the right data structure for different workloads.
This article explains how to design a live‑streaming danmaku (bullet‑screen) feature by using Redis Zset as the underlying data structure, limiting the list to the latest ten messages, and handling retrieval via polling APIs or WebSocket, with Kafka for message buffering and a distributed lock to avoid ordering issues.
Redis has launched an enhanced, multi‑threaded query engine that dramatically increases throughput and reduces latency for vector similarity searches, enabling vertical scaling and better support for real‑time RAG applications while maintaining sub‑10 ms response times.
This article explains how Redis implements dynamic string expansion using the Simple Dynamic String (SDS) structure, detailing the sdsMakeRoomFor function, its allocation strategy, type handling, and the architectural changes introduced in Redis 7.0.
This article provides a comprehensive guide to using Alibaba's JetCache in Java Spring Boot projects, covering dependency setup, configuration of local and remote caches, annotation‑based caching, API usage, testing procedures, and troubleshooting common integration errors.
This article introduces Alibaba's JetCache Java caching framework, explains how to integrate it with Spring Boot and Redis, provides detailed configuration and code examples for local, remote, and multi‑level caches, and covers testing procedures and common error resolutions.
A detailed post‑mortem of a Redis outage shows how a traffic surge filled bandwidth, caused massive input and output buffers to consume almost all memory, and led to timeouts, while offering step‑by‑step analysis, memory diagnostics, and practical recommendations to prevent similar buffer‑overflow failures.
This article provides a detailed, practical guide for increasing Redis memory on Linux by adjusting Redis configuration, expanding system swap space, tuning kernel overcommit settings, and monitoring usage with command‑line tools.
This article explores several strategies—timestamp with random numbers, MD5 hashing, UUIDs, and an optimized Base62 conversion combined with Redis‑based locking—to generate short, globally unique CDN file names for an OSS upload platform.
The course provides an in‑depth study of processes, socket communication (including TCP/IP), Nginx with FASTCGI, byte‑order conversion, and fundamental Redis operations, targeting backend developers, system administrators, and network engineers to comprehensively boost their backend development expertise.
PHPCreeper is a high‑performance PHP crawler built on Workerman that leverages asynchronous I/O, multi‑process, distributed deployment and headless‑browser support; this guide covers installation via Composer, core architecture, producer/downloader/parser implementation, Redis configuration and how to start the service to fetch dynamic pages such as weather forecasts.
This guide explains how to implement a Casbin Watcher for distributed policy synchronization using Workerman's asynchronous Redis client in PHP, covering the underlying principles, required interfaces, code implementation, and a complete usage example with publish‑subscribe messaging.
The article describes how an automated resource‑balancing system continuously monitors Redis host memory usage, selects optimal nodes, safely migrates them through a multi‑step process (adding slaves, verifying replication, promoting masters, deleting old nodes), and provides task management and notification features to maintain high availability and reduce manual DBA effort.
Redis 4.0 offers three persistence options—RDB snapshotting, AOF command logging, and a hybrid RDB‑AOF mode—each with distinct configurations, trigger conditions, and trade‑offs, and this guide walks through their principles, practical commands, performance impacts, and recovery procedures with detailed examples.
The article explains how to store and deduplicate billions of identifiers efficiently by using a bitmap backed by Redis and extending it with a Bloom filter implementation in Java, highlighting memory calculations, practical commands, and code examples.
This article demonstrates how to build a flexible API rate‑limiting solution in Spring Boot by combining a HandlerInterceptor, Redis counters, and custom annotations with reflection, covering configuration, code examples, mapping rules, time‑window nuances, path‑parameter handling, and real‑IP considerations.
This article introduces the new Redis book "Redis Mastery", explains core Redis concepts such as SDS strings, RDB/AOF persistence, master‑slave replication and Sentinel high‑availability, and also announces a limited‑time discount and giveaway for community members.
This article explains the Redisson IllegalMonitorStateException caused by unlocking a lock held by another thread, analyzes the underlying node‑id and thread‑id concepts, and presents several practical solutions to correctly manage distributed locks in Java applications.
Bilibili’s game live‑stream platform implements interactive features ‘Play Together’ and ‘Help Me Play’ by using Redis ZSET queues, MySQL persistence, real‑time streamer recommendation, ticket‑based purchase flows, state‑machine order handling, and comprehensive monitoring to ensure reliable, scalable viewer‑streamer gameplay collaboration.
This guide explains Redis's eight memory eviction policies, their algorithms, ideal scenarios, and step‑by‑step configuration via redis.conf, CONFIG SET, or command‑line options, helping you choose the right strategy to balance performance, data safety, and resource limits.
This article explains how to implement pagination, multi‑condition fuzzy search, and their combination using Redis Sorted Sets and Hashes, discusses performance optimizations and expiration strategies, and also contains promotional material for ChatGPT services and a community offering.
This article analyzes a Redis cluster outage caused by a slot‑migration bug where a node simultaneously migrated slots in and out, leading to conflicting config epochs, gossip‑protocol mismatches, and MOVED errors, and provides detailed troubleshooting steps and preventive measures.
The article chronicles the evolution of database technology from early hierarchical and network models through relational, column‑store, document, key‑value, graph, time‑series, HTAP, and finally vector databases, detailing each system’s architecture, strengths, limitations, typical uses, and future trends toward specialization, distributed cloud‑native designs, and AI‑driven applications.
This article explains the concept of request debouncing, identifies which API endpoints need it, and demonstrates two distributed lock solutions—shared Redis cache and Redisson—by providing complete Java code examples, configuration steps, and test results to prevent duplicate submissions in backend services.
This article provides a detailed, beginner‑friendly tutorial on purchasing an Alibaba Cloud ECS instance, configuring the operating system, and installing JDK 8, Redis, and MySQL 8.0—including necessary firewall and security‑group settings—to launch a functional web‑site environment.
This article explains Redis master‑slave replication, synchronization steps, handling of network partitions, and how Sentinel provides automatic failover through monitoring, leader election, and notification, offering strategies to reduce master load and ensure high availability.
Gotu’s Redis management platform now runs an unattended 5 AM scheduler that automatically selects and migrates nodes based on priority rules, verifies master‑slave synchronization, and rebalances host memory to stay below safe thresholds, improving utilization, reducing DBA effort, and supporting future auto‑deployment and recovery.
This article explains how to build a dynamic IP blacklist that blocks malicious crawlers or users by using Nginx with a Lua access script and Redis for storage, covering requirements, environment setup, design choices, configuration steps, Lua code, and advanced extensions.
This guide walks you through installing common backend services on CentOS—building Redis from source, deploying RabbitMQ via RPM, and adding Nginx with YUM—while explaining key concepts like tarballs, RPM metadata, and YUM repository configuration.
This article walks through using JetCache with Spring Boot 3.2.5, covering its features, Maven dependency setup, YAML configuration, annotation-based caching, programmatic cache creation, statistics monitoring, and deprecated APIs, all illustrated with code snippets and screenshots.
This article explains how to enable cross‑server WebSocket communication in a distributed Spring application by using a message queue such as Redis or Kafka, detailing two architectural approaches, concrete code examples, configuration files, and a sample client page.
This article explains how to implement distributed locks in Redis using the SETNX command, atomic Lua scripts, the Redisson Java client, and the RedLock algorithm, providing code examples and discussing their advantages and limitations in distributed backend systems.
Vivo’s storage team redesigned Redis cluster slot migration by disguising the target as a slave and using master‑slave replication with progressive loading, which eliminates ask‑move round trips, reduces latency spikes, consolidates topology updates, and ensures stable access and high availability during horizontal scaling.
This article explains how Redisson's DelayedQueue works internally, covering its data structures, the basic workflow for sending and receiving delayed messages, the initialization process, and the scheduling logic that moves expired items from the delay queue to the target queue.
This tutorial explains how to implement IP‑and‑URL rate limiting in a Spring Boot application by creating a custom HandlerInterceptor that tracks request counts in Redis, uses a distributed lock to enforce limits, and registers the interceptor to protect services from malicious or excessive traffic.
This article explains the internal structures of Redis data types—including strings, lists, sets, hashes, and sorted sets—detailing their memory representations, evolution across versions, time‑complexity characteristics, and the code implementations that enable efficient in‑memory operations.
This guide introduces the Python RQ library, shows how to install it with Redis, and provides multiple code examples covering queue creation, task execution, priority handling, timeouts, batch processing, scheduling, retries, and status tracking for building robust asynchronous back‑end systems.
To import one billion 1 KB log records stored in HDFS or S3 into MySQL efficiently, the article examines data partitioning, B‑tree index limits, batch insertion, storage engine choices, concurrency control, file‑reading methods, task scheduling with Redis, Redisson, and Zookeeper for reliable, ordered, high‑throughput loading.
This report analyzes performance bottlenecks caused by serialization in a search‑recommendation system, presents detailed measurements of request latency, evaluates multiple optimization strategies—including Redis caching, lazy metric handling, and custom byte‑array serialization—and documents the resulting latency reductions and implementation considerations.
This article explains how to implement an online‑user counter using Redis sorted sets by detailing the four essential ZSET commands, fingerprint‑based user identification, Java and JavaScript code examples, and scheduled cleanup for accurate real‑time statistics.
This article explains how to track online users using Redis sorted sets by describing the core ZSET commands (zadd, zrangeByScore, zremrangeByScore, zrem), showing code examples for adding, querying, and cleaning up user sessions, and discussing fingerprint-based identification methods.
By leveraging Redis sorted sets for ordered pagination and hash fields with HSCAN for multi‑condition fuzzy matching, the article shows how to build a cached query pipeline that creates temporary ZSets keyed by pattern, supports efficient page retrieval, and uses expirations and refresh strategies to balance freshness and performance.
This article compares three approaches for verifying username uniqueness during app registration—direct database queries, Redis caching, and Redis-backed Bloom filters—detailing their performance, scalability, memory usage, and trade‑offs, and provides Java code examples for each solution.
This article introduces the Redis in‑memory database, highlights the new "Redis Mastery" book that blends theory with practical examples, and explains core concepts such as SDS string structures, RDB/AOF persistence, master‑slave replication, and Sentinel high‑availability mechanisms.
The guide equips candidates for backend interviews by covering essential networking (HTTP/HTTPS, TLS handshake, status codes, headers, OCSP, session resumption, CSRF), RPC frameworks, Java class-loading and JVM memory/GC, OS process/thread scheduling, Spring bean lifecycle, Redis caching pitfalls, and MySQL indexing and query optimization.
The author reflects on a decade‑plus journey through China’s DTCC database conferences, describing personal growth from novice to speaker and organizer, sharing insights on Redis Cluster, distributed database selection, openGauss, time‑series databases, and the evolving themes that chart the industry's progress.
This tutorial explains how to implement API rate limiting in Spring Boot using the Bucket4j library, covering token‑bucket theory, Maven dependencies, Redis configuration, YAML rules, annotation‑based limits, custom responses, and conditional bypasses with complete code examples.
The article explains JWT fundamentals, shows how to integrate it with SpringBoot, compares JWT with a Token‑plus‑Redis approach, and argues why using JWT alone can be problematic in a system that already relies on Redis for session management.
Learn how to connect to Redis using redis-cli, select databases, list and manipulate keys, retrieve values, check database size, view server info, and perform full backups and restores, with clear command examples for each operation.
Lock4j is a Java distributed lock library supporting Spring AOP, RedisTemplate, Redisson, and Zookeeper, offering simple usage, configurable properties, annotation-driven locking, custom executors, key generators, and failure strategies, with detailed setup, code examples, and advanced customization instructions.
This article explains how to implement interface debounce in Java backend services, covering the concept, identifying suitable APIs, generating unique keys, and applying distributed locking mechanisms with Redis and Redisson, including code examples and practical testing results.
This article explains why API debounce is essential, identifies the types of endpoints that need it, and provides two distributed solutions—shared Redis cache and Redisson lock—along with complete Java code examples and deployment tips for preventing duplicate submissions in a Spring Boot backend.
This article examines the replication and partitioning designs of Redis, Kafka, and Elasticsearch, drawing on concepts from Designing Data‑Intensive Applications to illustrate core distributed‑system principles, common challenges, and practical configuration options.
This tutorial demonstrates how to perform fundamental Redis operations—including setting, retrieving, and deleting keys, working with hashes, lists, and sorted sets—using Python's redis client and includes complete test code for each scenario.
This article explains the four common Redis cache pitfalls—cache penetration, avalanche, breakdown, and data inconsistency—demonstrates how they can crash high‑traffic systems, and provides practical Java/Spring Boot solutions such as empty‑object caching, Bloom filters, distributed locks, and delayed double‑delete strategies.
The article explains why adopting a message‑queue improves microservice decoupling and responsibility boundaries, then details the design of a pluggable Base‑MQ component—including @MQEventListener, MQEvent base class, configuration, and MQClient interface—followed by concrete implementations for RocketMQ, Kafka, Redis and RabbitMQ, an example event flow, and guidance for extending the framework.
This article explains Redis persistence mechanisms (RDB and AOF), common caching challenges such as avalanche and penetration with mitigation techniques, outlines Redis data types and their use cases, compares cluster solutions, and details replication, transactions, and distributed locking strategies.
Redis has launched a multi‑threaded query engine that vertically scales its in‑memory database, dramatically increasing query throughput and lowering latency for vector similarity searches, thereby addressing the performance demands of real‑time retrieval‑augmented generation in generative AI applications.
Redis has introduced a multithreaded query engine that dramatically boosts throughput and lowers latency for vector searches, enabling scalable, real‑time retrieval‑augmented generation (RAG) workloads while preserving the low‑latency performance of its core in‑memory database.
This article introduces JetCache, an open‑source distributed caching framework built on Spring and Redis, outlines its key features and typical scenarios, and provides step‑by‑step guidance for integrating JetCache into a SpringBoot application with configuration examples and sample code.
This guide explains how to set up a Higress gateway, compile a WebAssembly AI cache plugin, integrate Redis and DashVector for semantic caching of large‑model requests, and provides complete configuration and code examples for end‑to‑end deployment.
This guide walks through ten common Redis tasks—setting and getting keys, deleting keys, listing keys, hash, list, set, sorted‑set operations, publish/subscribe, pipeline, and transactions—each illustrated with clear Python redis‑py code examples.
This article explains how to build high‑concurrency systems by analyzing single‑machine hardware and code optimizations, clarifying multithreading versus asynchronous methods, and then scaling horizontally and vertically with caching, partitioning, and distributed inventory management to achieve stable, performant services for large‑scale e‑commerce workloads.
This article explores the three‑high requirements of modern internet systems, compares multithreading with asynchronous methods, and presents a practical, partition‑based inventory‑deduction architecture that leverages Redis caching, MySQL sharding, and asynchronous updates to achieve scalable high‑concurrency performance.
This article explains the challenges of multiple product logins, reviews traditional session mechanisms, discusses session sharing solutions in clustered environments, and presents a CAS‑based single sign‑on implementation with Java code examples, highlighting differences between CAS and OAuth2 for secure authentication.
The article outlines nine broadly applicable techniques—caching, parallel and batch processing, data compression, lock‑free design, sharding, eliminating unnecessary requests, and resource pooling—that together can dramatically cut service latency and improve throughput, as demonstrated by an 80% latency reduction in a real‑world project.
This article explains how to use Redis for distributed locking, discusses the shortcomings of naive implementations, and presents robust solutions including identifier verification, Lua scripting for atomicity, the RedLock algorithm, and Redisson's advanced features such as re‑entrancy and watchdog mechanisms.
This article details the design, architecture, and Java implementation of a WebSocket‑based backend that enables real‑time, multi‑player quiz battles, covering entity definitions, message handling, matchmaking logic, error handling, game flow, and supporting utilities such as Redis‑based state management.
This article introduces Lock4j, a Java distributed lock library supporting RedisTemplate, Redisson, and Zookeeper, walks through its key features, dependency setup, configuration, annotation attributes, simple and advanced usage examples, and demonstrates custom executors, key builders, and failure strategies for robust concurrency control.
This article explains how to build an online user counting feature by leveraging Redis sorted sets (zset) in Java, covering user identification, the core Redis commands (zadd, zrangeByScore, zremrangeByScore, zrem), code examples, and periodic cleanup logic.
This article explains how to build an online user counting feature using Redis sorted sets (ZSET) by detailing the core commands (zadd, zrangeByScore, zremrangeByScore, zrem), user identification methods, and providing Java and JavaScript code examples, while also noting unrelated promotional content at the end.
Redis, an open-source in-memory NoSQL database, is explored in depth covering its high-performance features, typical use cases, evolution, architecture, data types and commands, followed by an overview of Tencent Cloud Redis services and a brief advertisement for a DevOps certification program.
This article explains how to prevent duplicate API submissions by applying debounce principles and implementing distributed locks using Redis and Redisson in a Java Spring backend, providing detailed code examples, key generation strategies, and practical testing results.
This comprehensive guide explains Redis persistence mechanisms—including RDB snapshots, AOF write‑ahead logging, and their hybrid mode—covering their workflows, configuration options, replication processes, performance trade‑offs, and practical tips for reliable data durability.
In 2023, a TapTap infra team reduced Redis operating costs by 460,000 CNY per month through low‑cost ESSD instances, traffic compression, unused‑instance cleanup, TTL management, data migration, online compression, and targeted cleaning, detailing ten concrete measures and the open‑source tools that enabled zero‑downtime optimization.
This article introduces lua‑resty‑redis, explains its non‑blocking I/O model, outlines typical use cases, details installation via OPM, provides step‑by‑step Lua code for basic operations and transactions, and demonstrates testing with curl, helping developers build high‑performance OpenResty services.
This guide demonstrates how to create a simple Go web API using the Gin framework, define a recipe data model, implement CRUD endpoints backed by MongoDB, add Redis caching for list queries, and provide a complete runnable example with testing scripts.
This article explores the benefits of short URLs, explains their redirection mechanics, compares hash‑based and auto‑increment generation methods, and presents a high‑throughput architecture using OpenResty, Redis, and MySQL to handle massive traffic while ensuring reliability and scalability.
The article examines why internet architectures have become increasingly complex, explains the unique challenges of flash‑sale (秒杀) business scenarios, and presents practical backend optimization techniques such as request filtering, Redis caching with atomic operations, ordered queues, data‑layer safeguards, and unit‑based isolation for global deployments.
Valkey, a Linux Foundation‑backed fork of Redis released under a BSD license, offers faster development, stronger community governance, and new performance and cloud‑native features, positioning it as a compelling alternative for modern workloads.
This guide explains how to implement an online user counting feature using Redis sorted sets, covering user identification methods, the essential zadd, zrangeByScore, zremrangeByScore, and zrem commands, along with code examples and a concise summary of the overall approach.
Explore nine major database technologies—from traditional relational MySQL to NoSQL Redis, columnar HBase and ClickHouse, document-oriented MongoDB, search engine Elasticsearch, graph Neo4j, time‑series Prometheus, and vector Milvus—plus practical best‑practice guides, real‑world polyglot persistence scenarios, and recommended resources for mastering modern data storage.
This tutorial explains how to leverage Redis Stack modules—especially RediSearch and RedisJSON—to store movie data, build a searchable JSON index, and perform advanced full‑text queries, highlighting, sorting, pagination, custom tokenization, scoring, and index aliasing, with Go code examples.
This article explains how to implement a Redis distributed lock, covering the basic SETNX approach, adding expiration, handling lock release errors with renewal and unique identifiers, achieving atomicity via Lua scripts, and discussing the inherent challenges of network delay, process pause, and clock drift in distributed systems.
This article explains how Redis handles memory exhaustion by configuring maxmemory and maxmemory-policy, detailing each eviction strategy (noeviction, volatile‑lru, volatile‑lfu, volatile‑ttl, volatile‑random, allkeys‑lru, allkeys‑lfu, allkeys‑random), their implementation details, and the underlying approximate LRU algorithm.
This article provides an in‑depth survey of nine database categories—including relational, key‑value, columnar, document, graph, time‑series, and vector databases—detailing their architectures, advantages, disadvantages, best‑practice recommendations, typical use cases, and how they can be combined in polyglot persistence solutions.
This guide walks through creating a lightweight SpringBoot cache component using custom @Cacheable and @CacheEvict annotations, configuring Redis, implementing an AOP aspect to handle caching logic, and demonstrating usage with sample services and controller endpoints, while also discussing key generation and potential enhancements.
