System designHardsd-g508

Subject Messaging queuesLevel Senior–Staff~45 minCommon in Algorithms & data structures interviewsIndustries Technology, Software development

Question

Design a multi-priority job queue at scale: 8 priority levels, 200K enqueues/sec, thousands of competing tenants, workers pull the highest-priority ready job. Requirements: high-priority jobs must start within 2s, but no tenant's low-priority work may starve indefinitely, and a single noisy tenant must not monopolize a priority level. Jobs have per-tenant concurrency limits.

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.