Question library
Questions from real interviews. Drill any of them by voice in a couple of minutes, with an interviewer, a score and feedback.
What's the difference between ETL and ELT?JuniorA daily pipeline loads yesterday's data into the warehouse. Sometimes it fails halfway through, and after a restart duplicates show up in the table. How would you redesign it?Mid-levelDesign an analytical data warehouse for a mid-sized online store: the data comes from the product Postgres database, a CRM and ad platforms, and the consumers are BI dashboards and analysts. Walk me through how you'd set it all up.Mid-levelDesign a system of daily batch pipelines for several hundred tables with dependencies between them. How would you handle reruns, backfills and late-arriving data?SeniorYou need to deliver changes from a multi-terabyte production PostgreSQL database to an analytics warehouse with no more than five minutes of latency. How would you design this pipeline?Senior