System Design · Disney · Medium
Design a system for flash sales or ticket booking that can handle extremely high concurrency. When a sale opens, users are placed in a virtual waiting queue before they can try to buy. The design is graded on three focus areas: Queuing service: a component that controls and throttles how fast users are let in from the waiting queue to the purchase flow. Inventory decrement: reduce stock correctly at very high throughput without ever selling more units than exist. The…