Start by clarifying functional and non-functional requirements, then sketch a high-level architecture that separates read-heavy browsing from write-heavy seat locking. Focus on the seat hold mechanism using a distributed lock or atomic conditional write with TTL, and discuss scaling strategies for traffic spikes.
Pro tip: Emphasize idempotency and graceful degradation: use idempotent APIs for hold and purchase operations, and design the system to shed load or queue users during extreme spikes to protect core booking integrity.
Ask about scale (events, users, seats), consistency needs, and payment integration. Define core entities: events, venues, seats, holds, orders.
Propose a microservices or modular architecture with separate services for browsing (read-heavy) and booking (write-heavy). Use CDN and caching for event/seat maps.
Design a seat hold service using a distributed lock (e.g., Redis with TTL) or atomic conditional writes in a database. Ensure holds expire after 5 minutes and are released automatically.
Address spikes with horizontal scaling, load shedding, queueing (e.g., virtual waiting room), and read replicas. Use partitioning by event to distribute load.
Define schemas for events, seats, holds, and orders. Discuss trade-offs between strong consistency (for seat locking) and eventual consistency (for browsing).
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.