The article explains how sampling serves as the cost‑fidelity knob in distributed tracing, why full sampling collapses at ten‑million QPS, compares head‑based, tail‑based, and intelligent adaptive strategies, and shows how tools like OpenTelemetry, Jaeger, and AWS X‑Ray implement these approaches.
This article details how to design a unified authentication center that can handle billions of OAuth 2.0 requests, covering layered architecture, token issuance and revocation, refresh‑token rotation, gateway validation, key management, and practical pitfalls to ensure secure, high‑performance identity traffic in production.
At billion‑level request rates, the traditional cache‑aside pattern fails, so the article proposes a three‑layer architecture—Canal captures MySQL binlog, an MQ (RocketMQ/Kafka) buffers changes, and a coordinated local cache service updates L1 caches with short TTL, achieving high performance and eventual consistency.
