I went straight to the database approach because that's what I'd actually do in production, but I think I undersold the tradeoffs.
Start by clarifying the application's requirements, such as scalability, fault tolerance, and session data complexity. Then compare sticky sessions and database-backed sessions across dimensions like scalability, availability, performance, and operational overhead. Finally, recommend a solution based on trade-offs, possibly a hybrid approach, and justify it with concrete examples.
Pro tip: At Amazon, always tie your answer back to customer impact and operational excellence—explain how each option affects availability, latency, and cost, and mention that you'd validate assumptions with load testing and metrics.
Ask about expected traffic scale, session data size and complexity, latency requirements, and availability targets. This ensures your recommendation is context-driven.
Discuss pros: simplicity, low latency, no external dependency. Cons: uneven load, poor fault tolerance, scaling challenges, and session loss on instance failure.
Discuss pros: stateless servers, easy horizontal scaling, session persistence across failures. Cons: added latency, database load, potential single point of failure, and complexity.
Evaluate both options against scalability, availability, performance, cost, and operational complexity. Consider hybrid approaches like using a distributed cache (e.g., Redis) as a session store.
Choose an option based on the requirements, explain why it's the best fit, and mention how you'd mitigate its drawbacks (e.g., database sharding, caching, or session replication).
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.