System design interview question
Design a Real-Time Analytics Event Processing System (like Segment or Mixpanel)
Design a distributed event processing system that ingests behavioral events from mobile and web clients across 50 million users, processes 500K events per second at peak, and serves analytics queries with sub-second latency. The system must handle geographic distribution across 3 continents, provide real-time dashboards for business metrics, support complex filtering and aggregation queries over events ingested in the last 90 days (approximately 1.3 trillion events), guarantee at-least-once delivery of events, and maintain sub-100ms query response times for dashboard queries while ensuring high availability and fault tolerance. Design the complete system including event ingestion, stream processing, storage, query layer, and caching strategies.
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