LuTiao Programming

Sep 27, 2026 · Backend Development

Why the 101st Waitlist User Never Gets Skipped: Atomic Promotion with MySQL Row Locks

This article demonstrates how to implement a correct waitlist auto-promotion system for limited-capacity events using Spring Boot, MySQL InnoDB row locks, and database transactions to atomically handle cancellations and promotions without race conditions, ensuring the first waitlisted user always gets the freed spot.