System designHardsd-g516

Subject Change data captureLevel Senior–Staff~50 minCommon in Distributed systems interviewsIndustries Technology, Software development

Question

Design a change-data-capture pipeline that streams every insert/update/delete from a fleet of production OLTP databases into a data lake and several downstream consumers, with no gaps and no double-counting. You must handle initial backfill of huge existing tables, then switch seamlessly to live tailing, survive DB failovers, and propagate schema changes (a column added/renamed) without breaking consumers. Scale: 500 tables, 1M row-changes/sec aggregate.

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.