Distributed Systems

Prerequisite: Part 9 of the System Design Masterclass. Read Part 4: Database Scaling for context on horizontal partitioning strategies. Answer-first: Consistent Hashing minimizes key remapping when cluster membership changes. Adding or removing one node from a modulo-hash cluster remaps nearly all keys (catastrophic cache miss storm). Consistent Hashing remaps only $K/N$ keys — the theoretical minimum necessary. Why Modulo Hashing Fails When Scaling Answer-first: hash(key) % N changes to hash(key) % (N+1) when a node is added, causing nearly all key-to-node mappings to change. This creates a massive cache miss storm as the entire working set must be reloaded from the database simultaneously. ...

Prerequisite: This is Part 1 of the System Design Masterclass series. Familiarity with basic distributed systems concepts and Go syntax is assumed. Answer-first: Sound system design thinking is fundamentally about evaluating and selecting trade-offs across performance, reliability, and cost. No system is perfect — architects optimize for the constraints imposed by real business requirements and technical realities. How Do You Build System Design Thinking? Answer-first: System design mastery is built on three pillars: mastering foundational theorems (CAP, PACELC), practicing trade-off analysis on real-world case studies, and repeatedly decomposing large problems into measurable, independently scalable components. ...

Answer-first: How Alipay’s engineering team scaled Double 11 to 583,000 TPS using LDC unitization, OceanBase, RocketMQ, and SOFAStack. A 2026 deep-dive. At midnight on November 11th, approximately 1.5 billion people across Asia collectively open a single app and start tapping “Buy Now.” In the first 60 seconds, Alipay processes more transactions than a major Western bank handles in an entire day. The 2023 Singles’ Day peak — 583,000 payment transactions per second (TPS) — is not just a headline. It is the product of fourteen years of architectural evolution that has redefined what “production-ready” means for a financial platform. ...