A 2-billion-row Postgres orders fact serves a quarterly report that aggregates two or three columns
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 2-billion-row Postgres orders fact serves a quarterly report that aggregates two or three columns per query, but the dashboard takes 18 minutes because Postgres reads every column of every row. Apply the section's columnar-vs-row framing and replace the row-stored fact with a columnar destination so the I/O reduction, compression, and vectorized execution wins all apply.
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