Former senior tech manager at Meituan, ex‑tech director at New Oriental, with experience at JD.com and Qunar; specializes in Java interview coaching and regularly shares hardcore technical content. Runs a video channel of the same name.
This article explains why Java’s Lock interface is still needed despite synchronized, covering non‑blocking tryLock, timed lock acquisition, interruptible locking, fair versus non‑fair locks, read‑write locks, and Condition objects, with code samples and execution logs illustrating each feature.
This article compares API composition and CQRS patterns for handling distributed queries in evolving monolithic systems, illustrating their workflows with e‑commerce and online‑education examples, discussing performance trade‑offs, implementation details using Canal and ElasticSearch, and offering practical guidance on when to adopt each approach.
This article compares ClickHouse and MySQL by examining benchmark results, MPP architecture, columnar storage, compression techniques, vectorized execution, and index designs, showing why ClickHouse delivers dramatically higher query performance on massive data sets.
This article examines the debate over sharing versus isolating databases in microservice architectures, presents arguments from both sides, shares a detailed incident from an online education platform, and outlines best‑practice recommendations for balancing availability, cost, and development efficiency.
This article demonstrates how to identify long‑method and duplicated code smells in a Java curriculum‑display service and refactor the implementation using the Decorator pattern, providing clear component diagrams, full code examples, and a runnable demo that showcases flexible extensions for different course types.
This article explains MySQL’s composite index leftmost‑prefix rule, demonstrates how the Skip Scan Range Access Method introduced in MySQL 8.0.13 can use indexes without following the rule, provides step‑by‑step examples, code snippets, and discusses its implementation, benefits, and limitations.
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 explains MySQL's hash join algorithm, compares it with nested‑loop joins, shows how to read execution steps and EXPLAIN output, discusses extended hash‑join scenarios, and weighs the trade‑offs of performing multi‑table joins inside the database versus in application code.
This article uses a realistic interview scenario to explore why multi-table joins in MySQL are not inherently slow, detailing four join algorithms—simple nested-loop, index nested-loop, block nested-loop, and batched key access—along with their pseudo‑code, execution steps, performance trade‑offs, and the impact of features like MRR and recent optimizer changes.
A daily million‑order e‑commerce platform only generates about 30 TPS, making inventory‑deduction and oversell concerns trivial and solvable with a single atomic SQL update rather than complex distributed solutions.
