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I started with the usual capacity estimates and that ate up more time than I wanted.
Start by clarifying requirements and scale (e.g., events per day, concurrent users, peak load), then design a high-level architecture focusing on core components like event catalog, seat inventory, booking, and payment. Dive into critical challenges such as concurrency control for seat locking, data consistency, and scalability, discussing trade-offs and technologies (e.g., distributed locking, caching, sharding).
Pro tip: Emphasize the importance of handling peak traffic and preventing double-booking through optimistic locking or distributed locks, and discuss how to ensure high availability and fault tolerance. Show awareness of real-world constraints like payment gateway integration and regulatory compliance.
Ask questions to understand expected traffic, number of events, concurrent users, and peak load scenarios. Define functional and non-functional requirements (e.g., latency, consistency, availability).
Outline main components: event service, seat inventory service, booking service, payment service, notification service, and user management. Sketch data flow and interactions.
Focus on seat selection and locking mechanism to prevent double-booking, using techniques like optimistic concurrency control or distributed locks. Discuss data modeling for events, seats, and bookings.
Explain how to scale each component: caching (e.g., Redis for seat maps), database sharding (by event or geography), load balancing, and asynchronous processing for notifications.
Discuss trade-offs between consistency and availability (CAP theorem), and how to handle failures (e.g., retries, idempotency, circuit breakers). Mention monitoring and alerting.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.