Batch photo processing pipeline
Design the batch image-processing pipeline for a photo-cloud product that, on upload, must run a chain of ML and CV steps per photo — EXIF extraction, face detection + clustering, object/scene labels, OCR, and NSFW screening — for 2B photos/day, and must also support re-running the whole chain over the entire 500B-photo back-catalog when a model is upgraded. Design the per-photo pipeline, how you schedule the steps, and how you do a full backfill without melting the live ingest path.
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.
Clarify5:00 left
Estimate5:00 planned
Design15:00 planned
Deep dive12:00 planned
Failure8:00 planned
Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.
Run or narrate your approach, then ask the coach.