This article explains how to design and implement a WeChat group red packet feature, covering database schema, non‑cached and cached workflows, concurrency control with Redis locks, and two allocation algorithms—random distribution and double‑average method.
During Double‑11, the team created two specialized allocation algorithms—a brand‑score‑driven primal‑dual method for guaranteed‑downline contracts and a guarantee‑and‑balance flow‑re‑ranking approach for guaranteed‑non‑downline contracts—both using near‑line dual adjustments to meet contract volumes while boosting interaction depth, repeat visits, and browsing time.
This article explains why elastic scaling is needed for variable web traffic, describes how to build a cost‑effective, automatically adjustable service on Alibaba ECS using message queues, service refactoring, Docker deployment, logging, and a real‑time allocation algorithm, and shares practical lessons learned.
