System designHardsd-g339

Subject Search systemsLevel Senior–Staff~50 minCommon in Databases & SQL · Distributed systems interviewsIndustries Technology

Question

Design a globally-distributed search index for a SaaS where merchants in the US, EU, and APAC all need < 30ms search latency from their nearest region, but the catalog is written from one merchant's primary region and must appear in search worldwide within ~10s. 100k tenants, hugely skewed (one tenant has 50M products, most have a few thousand). How do you replicate the index across regions, keep all regions fresh, and handle the giant tenant without it starving the small ones?

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.