System designHardsd-g668

Subject Database hot partition mitigationLevel Senior–Staff~40 minCommon in Databases & SQL · Reliability & on-call · Distributed systems interviewsIndustries Technology, Software development

Question

Design hot-partition mitigation for a DynamoDB-style key-value store where a few celebrity entities (a viral post, a flash-sale SKU) receive 100x the traffic of an average partition, causing throttling on those partition keys while the cluster is mostly idle. Writes are 30k/sec aggregate but spike to 50k/sec on a single key. How do you detect, spread, and absorb the hot key without over-provisioning everything?

What a strong answer looks like

Clarify scale and constraints first. Propose a clean component breakdown, then go deep on the hard parts — data model, bottlenecks, consistency, failure modes — and name the trade-offs you are making.

Learn the concepts

Narrate your design

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Run or narrate your approach, then ask the coach.