The Vital Few
A medium Data Modeling 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
- Data Modeling
- Difficulty
- medium
- Seniority
- L5
Interview Prompt
We ingest about 2TB of raw application logs into S3 every day, where debug and info lines vastly outnumber the errors analysts actually care about, so the high-value error records need to live apart from the bulk firehose. Analysts follow a single request as it crosses services and stitch a user's activity together within a session, starting from either an ordinary log line or an error, so the request and session identifiers have to ride on both. Errors are grouped by a canonical category instead of raw message text, and error rates get sliced by the team that owns each service and its tier, so keep that ownership one hop away.
Summary
Two terabytes a day, and the lines that matter are a rounding error in the noise.
How This Interview Works
- Read the vague prompt (just like a real interview)
- Ask clarifying questions to the AI interviewer
- Draw your data model on the schema canvas: tables, keys and relationships
- Answer the interviewer's follow-up questions, then get a hire or no-hire decision