Joined Tencent (nicknamed "Goose Factory") through campus recruitment at a second‑tier university. Career path: Tencent → foreign firm → ByteDance → Tencent. Started as an interviewer at the foreign firm and hopes to help others.
Learn four practical techniques—simple sorting, hashmap deduplication, external merge sort, and bitmap bit‑set optimization—to efficiently remove duplicate QQ numbers from a 40‑billion‑record file while staying within a strict 1 GB memory limit, even handling tighter 100 MB constraints.
This article explains the core purpose of MySQL indexes, enumerates twelve typical situations that cause index failure, provides concrete SQL examples and corrections, and shows how to use EXPLAIN to diagnose and verify index usage for better query performance.
This article explains how InnoDB's redo log works as a safety cushion, detailing its generation, buffering, flushing, circular storage, and recovery process to ensure transaction durability even when the database crashes unexpectedly.
This article explains what QPS (queries per second) really means, distinguishes it from TPS and concurrency, shows typical QPS ranges for different systems, and provides practical methods—production monitoring, APM tools, custom metrics, load‑testing and manual estimation—to obtain, validate, and interpret QPS for performance optimization and interview success.
This article explains what message queue backlog is, why it harms system latency, and provides practical, step‑by‑step strategies—including temporary consumer scaling, prioritizing core messages, queue splitting, root‑cause analysis, performance tuning, message design, dead‑letter handling, traffic control, capacity planning, and monitoring—to eliminate backlog and ensure reliable asynchronous processing.
Learn how to design and implement automatic order expiration in e‑commerce systems using three approaches—simple scheduled table scans, delayed message queues, and a Redis time‑wheel—detailing their trade‑offs, code examples, indexing tips, distributed locking, and failure‑handling strategies.
This article walks developers through the evolution of distributed system architectures—from single‑machine deployments to master‑slave, same‑city active‑active, and finally true multi‑active setups—explaining core concepts, replication strategies, conflict resolution, fault detection, switch mechanisms, recovery methods, and interview tips for high‑availability design.
Java’s HashMap tackles hash collisions through a combination of perturbation functions, chaining, open addressing, and, since JDK 8, converting long chains into red‑black trees, with detailed explanations of the underlying algorithms, resizing mechanics, threshold choices, and performance trade‑offs for developers and interview candidates.
This article introduces Redis HSET, covering its definition, suitable use cases, common commands for creating, reading, updating, and deleting hash fields, as well as the underlying encoding mechanisms (ziplist vs hashtable) and best practices, including the deprecation of HMSET.
This article introduces Redis Sets as unordered unique string collections, explains their ideal use cases, and provides detailed walkthroughs of creation, query, update, and deletion commands—including SADD, SREM, SISMEMBER, SCARD, SMEMBERS, SSCAN, SINTER, SUNION, and SDIFF—along with underlying encoding mechanisms.
