Concepts
Short reference pieces on the primitives system design questions keep reaching for — caching, connections, APIs, storage.
Articles
Reference: Database Indexing
A reference on B-Tree vs LSM-Tree storage engines, composite index column ordering, covering indexes, and where secondary indexes create hot shards.
Reference: Common System Design Decisions
A fast-lookup catalog of recurring system design choices — storage, performance, architecture, reliability — each with a default and when to switch away from it.
Reference: Capacity Estimation
A short reference on interview capacity math — QPS, storage, and bandwidth estimates, the numbers worth memorizing, and turning arithmetic into design conclusions.
Reference: Consistency Models
A short reference on consistency guarantees from linearizable to eventual — what each promises, what it costs, and how CAP and PACELC frame the choice.
Reference: Partitioning Strategies
A short reference on hash, range, and consistent-hash partitioning — how each distributes data, what breaks with each, and how to pick a partition key.
Reference: Queue Delivery Semantics
A short reference on at-most-once, at-least-once, and exactly-once delivery — where each guarantee actually comes from, and what replay and idempotency add.
Reference: Replication Strategies
A short reference on leader-follower, multi-leader, and leaderless replication — failure behavior, lag anomalies, and quorum arithmetic for each.
Reference: NoSQL Hot Key Mitigation Patterns
A short reference on hot key patterns in distributed NoSQL systems — what causes them, and the static and dynamic strategies for mitigating them.
Reference: Consecutive Activity & Retention Aggregation
A reference on computing streaks and retention over massive event streams — pre-aggregation, state slimming, and the bitmap, gaps-and-islands, and streaming techniques per time grain.
Reference: Distributed Transaction Patterns
A deep reference on distributed transaction patterns — 2PC, 3PC, and saga — their sequences, failure modes, and when to reach for each.
Reference: API Design Patterns
A short reference on REST vs gRPC, versioning, pagination, idempotency, and the small decisions that separate a designed API from an improvised one.
Reference: Cache Access and Invalidation Patterns
A reference on read/write caching patterns, invalidation strategies, and the classic failure modes — penetration, breakdown, avalanche — and how to avoid each.
Reference: Rate Limiting Algorithms
A short reference on the four canonical rate limiting algorithms — token bucket, leaking bucket, fixed window, and sliding window — with when to pick each.
Reference: Real-Time Connection Patterns
A short reference on HTTP polling, long-polling, SSE, WebSocket, WebRTC, and push notifications — which to reach for and why.
Reference: SQL vs NoSQL Schema Design
A short reference on when to pick SQL vs NoSQL, how to model schemas in each, and how to avoid hot keys.