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This article explains how IP packets are encapsulated, how TTL limits their lifespan, and how traceroute (or tracert) leverages TTL to reveal each network hop, illustrated with a step‑by‑step trace from a personal computer to GitHub’s servers.
This article explains the limitations of Java's ThreadLocal and InheritableThreadLocal in thread‑pool scenarios, introduces Alibaba's open‑source TransmittableThreadLocal (TTL) library, and provides detailed code examples for safely transmitting thread‑local data across threads, thread pools, and even via Java agents.
This article explains why message queues are needed, outlines RabbitMQ's architecture, describes its basic concepts and working modes such as simple, work, fanout, direct and topic, and discusses reliability features like transactions, confirms, dead‑letter queues, TTL, clustering, ordering, and handling message backlogs.
Learn how to seamlessly integrate Spring Data Redis Repositories in a Spring Boot 2.7 environment, covering object mapping, CRUD operations, indexing with @Indexed, query‑by‑example, batch saves, and setting expiration using @TimeToLive, complete with code examples and visual data representations.
This article explains the concept of distributed locks, illustrates real‑world scenarios such as concurrent ATM transactions, and details how to implement reliable distributed locking with Redis using TTL keys, SETNX, Lua scripts, lock renewal, high‑availability considerations, and the RedLock algorithm.
To replace Elasticsearch, the team built a ClickHouse‑based log platform that uses table‑level TTL and custom storage policies to automatically move data among hot (ESSD PL1), cold (ESSD PL0) and archive (OSS) disks, achieving faster writes, comparable query latency, and over 50 % cost reduction.
This article presents a comprehensive approach to optimizing Log4j2 logging in high‑traffic Java services by reducing disk and CPU consumption through log level control and pattern tuning, adopting asynchronous logging, and enabling end‑to‑end request traceability using ThreadLocal, TransmittableThreadLocal, and MDC techniques, supported by performance test results and practical recommendations.
This article explains Redis's in‑memory database architecture, detailing data locality, various eviction policies such as LRU, LFU, random and TTL, their configuration via maxmemory settings, and provides code examples of the eviction process and memory‑freeing functions.
This article explains the purpose of message queues, outlines RabbitMQ's architecture, describes common MQ patterns such as simple, work, fan‑out, direct, and topic, and discusses reliability features like transactions, confirms, dead‑letter queues, TTL, clustering, and ordering guarantees.
This article explains how to replace database‑polling scheduled jobs in e‑commerce systems with RabbitMQ delayed queues by leveraging dead‑letter exchanges and message TTL, providing step‑by‑step configuration, code examples, and deployment details for Spring Boot applications.
This article explains the concept of RabbitMQ dead letter queues, outlines the conditions that generate dead letters, provides step‑by‑step configuration instructions, and includes Go code examples for publishing messages with TTL and consuming from the dead‑letter queue to implement delayed processing.
This article provides a concise tutorial on essential Redis commands, covering basic operations, database selection, key management, expiration settings, and practical examples demonstrated through the Redis CLI, including how to list keys with patterns, check existence, and clear databases.
This article examines the challenges of storing massive DMP data in Redis, analyzes memory fragmentation, key‑size issues, and latency constraints, and presents practical strategies such as TTL eviction, bucket‑hashing, custom key compression, and fragmentation‑reduction techniques to enable scalable, real‑time querying.
This article explains how Redis handles key expiration, the commands for setting TTL, the three expiration strategies, the eight eviction policies, and the internal LRU and LFU algorithms, including their implementation details, sampling techniques, and configuration parameters for memory management.
This article explains the role of message queues in asynchronous processing, application decoupling, traffic shaping and log handling, compares popular MQ products, details RabbitMQ concepts and common patterns, and discusses reliability, ordering, dead‑letter, TTL and clustering strategies.
The article explains how to reliably propagate country‑specific context across request handling, database access, and asynchronous thread pools in multi‑country e‑commerce by replacing simple ThreadLocal and InheritableThreadLocal with Alibaba’s TransmittableThreadLocal, demonstrating its integration with Spring MVC/Boot, MyBatis, Dubbo, and custom executors for both sharded and non‑sharded databases.
This article explains why consumer‑side flow control is needed in RabbitMQ, demonstrates how to use the QoS API and basicQos settings, shows practical Java code for limiting consumption, and covers TTL and dead‑letter queue configurations to improve message reliability and system stability.
This article explains how to implement consumer-side flow control in RabbitMQ using QoS settings, demonstrates configuring prefetch limits, shows how to set message and queue TTLs, and provides step‑by‑step code examples for creating producers, consumers, and dead‑letter queues to manage message overload and expiration.
This article explains Redis's expiration policies, detailing how commands like DEL, SET, INCR, LPUSH, PERSIST, RENAME, EXPIRE, and EXPIREAT affect key TTLs, and describes the lazy and periodic deletion mechanisms used by Redis to manage expired keys.
This article explains how to build a basic SMS verification feature by choosing a gateway, generating and storing 4‑digit codes in MongoDB with TTL, and validating them through a simple backend workflow using Node.js and Mongoose.