Backend Engineering
Caching
6 practice questions. Free questions open a full answer guide; the rest unlock with Pro.
- A popular cache key expires and your database suddenly gets hammered by a flood of concurrent requests all trying to recompute the same value. What is this, and how do you prevent it?
- When you put a cache in front of a database, how do you decide on a write strategy, and how do you keep the cache from serving stale data?Go Pro
- Why is choosing a cache TTL tricky, and what's the cache stampede problem when a popular entry expires?Go Pro
- Your read-heavy service uses a distributed cache in front of the database. When a hot key expires, the database briefly gets slammed by a flood of identical requests. Beyond just raising the TTL, how would you design the caching layer to prevent this at scale?Go Pro
- Walk me through how you decide between write-through, write-behind, and cache-aside for a given workload, and how each choice affects consistency between the cache and the source of truth.Go Pro
- What is caching, where would you add one in a typical web application, and how do you decide what to cache?Go Pro
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