The Materialization Storm
A hard AI Coding mock interview question on DataDriven, with an AI interviewer who asks follow-up questions and a hire or no-hire decision at the end.
- Domain
- AI Coding
- Difficulty
- hard
- Seniority
- L6
Interview Prompt
Since we added 50 per-tenant dynamic-partition assets to dagster_repo/assets.py, the Dagster scheduler has pegged at 100% CPU queuing about 12,000 materialization runs an hour where roughly 50 should do, and tests/test_no_runaway_runs.py reproduces the blow-up for a single tick. Fix the asset graph so one tick stops rebuilding the same tenant partitions over and over, while every tenant's recommendations are still built from its user profile data. Be ready to defend what your fix trades away.
Summary
The graph started eating itself.
How This Interview Works
- Read the task and the repository: the files, the failing check and the constraints
- Work the fix with the AI agent at your side, and run the checks until they pass
- Submit, then answer the interviewer's questions about the change you made
- Get a hire or no-hire decision with feedback on how you drove the agent