A read-heavy service sends every request to a database that is slower and more expensive per read than memory, and the same few rows are asked for over and over.
Infrastructure, platform and reliability engineers.
Your approach: Use diagrams or prose to explain responsibilities, state, capacity and failure behavior. Show the calculations requested by the question.
Cache-Aside (Lazy Loading). A read-heavy service sends every request to a database that is slower and more expensive per read than memory, and the same few rows are asked for over and over. Work from the scoping questions below. State assumptions for any unspecified load, guarantee or target, then trace your design end to end. Explain one difficult case and a credible alternative; the worked example is a reference, not a required implementation.
Resolve the scoping questions for Cache-Aside (Lazy Loading). Separate stated behavior from assumptions, and identify what is outside your design.
Declare relevant volume, latency, freshness, quality or cost targets with units. Show calculations or an evaluation plan that can test them; unspecified targets are your assumptions, not hidden pass criteria.
Explain how your guarantees hold in a difficult case relevant to this subject. Address: How much traffic can the database absorb during a cache outage? Which values should never enter a shared cache?
Identify users, required behavior and exclusions. Answer: Which reads repeat, and how skewed is their popularity? How stale may a cached value be after a write?
Define the information owned by the system and the inputs, outputs and errors at its boundaries. Resolve: What happens when a popular entry expires? How much traffic can the database absorb during a cache outage?
Estimate the dominant workload and resource demand with units and explicit assumptions. For a learned system, also state how quality is measured and what data is available.
Draw or describe the responsibilities needed for Cache-Aside (Lazy Loading). Trace a representative request, event or job from its input to a visible result; identify durable state owners.
Walk through a difficult case step by step, including detection and recovery. Consider: Which values should never enter a shared cache?
Compare a credible alternative using your chosen workload and guarantees. Explain a remaining risk, a signal to watch and when you would change the design.