A product catalog service written in Python gets tens of thousands of read requests per second, and the database can't keep up anymore. How would you design caching?
~10 min by voice
How to approach it
The interviewer checks whether the candidate can design a cache as a system rather than just "put Redis in": start from the load profile and acceptable staleness, choose a strategy and invalidation approach, plan for failure scenarios (stampede, Redis going down, races), and measure the effect with metrics.
The interviewer will ask this question and listen. Think out loud and ask for a hint if you need one. When you're done, pause or tap “That's my answer”. In about a minute, your score and the points you covered show up here.