Three Postgres sources need CDC
A medium Pipeline Design mock interview question on DataDriven. Practice with AI-powered feedback, real code execution, and a hire/no-hire decision.
- Domain
- Pipeline Design
- Difficulty
- medium
Interview Prompt
Three Postgres sources need CDC. orders has 10M writes per day; doubling that with triggers would force a larger instance. shopping_cart deletes are critical to capture and the existing query-based ingestion misses them. legacy_events runs on a hosted Postgres without WAL access, so log-based CDC is unavailable. The section names three CDC families: trigger-based (captures deletes; doubles writes), query-based (cheap; misses hard deletes), and log-based (low overhead; needs WAL access and slot management). Identify the CDC family by replacing each source's ingest transform with one whose name states the chosen family and the deal-breaker that ruled out the alternatives.
How This Interview Works
- Read the vague prompt (just like a real interview)
- Ask clarifying questions to the AI interviewer
- Write your pipeline design solution with real code execution
- Get instant feedback and a hire/no-hire decision