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Online Schema Migration on a Billion-Row Table

A hard 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
hard
Seniority
staff

Interview Prompt

Our product team needs a new column added to the orders table - which has grown to a billion rows and receives 50K writes per minute. The migration must go live next week and production availability cannot be impacted. Design the migration approach and the backfill strategy.

How This Interview Works

  1. Read the vague prompt (just like a real interview)
  2. Ask clarifying questions to the AI interviewer
  3. Write your pipeline design solution with real code execution
  4. Get instant feedback and a hire/no-hire decision