A mobile SDK queued a checkout_completed event with event_time Tuesday 09:14 on a phone with patchy
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
A mobile SDK queued a checkout_completed event with event_time Tuesday 09:14 on a phone with patchy reception. The phone reconnected Thursday 14:27 and the event arrived at the pipeline two days late. The section names three things a pipeline can do with a late event: include it in its event-time bucket and update history, include it in the bucket of when it arrived, or drop it. The first is correct but mutates yesterday; the second is wrong but cheap; the third is wrong but predictable. Place the late event on the canvas: replace the processing-time aggregation with one that buckets by event time, and add a node whose name states which of the three reactions the pipeline now uses.
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