Compression

Concepts covered: paCompression

What They Want to Hear 'Snappy for interactive queries because it decompresses fast. Gzip for archival because it compresses more. Zstd is the emerging winner: Gzip-level compression at nearly Snappy-level speed.' That is the complete answer. They are testing whether you understand the speed-vs-ratio tradeoff, not whether you know the algorithms' internals.

About This Interactive Section

This section is part of the Where Data Lives: Beginner lesson on DataDriven, a free data engineering interview prep platform. Each section includes explanations, worked examples, and hands-on code challenges that execute in real time. SQL queries run against a live PostgreSQL database. Python runs in a sandboxed Docker container. Data modeling problems validate against interactive schema canvases. All content is framed around what data engineering interviewers actually test at companies like Meta, Google, Amazon, Netflix, Stripe, and Databricks.

How DataDriven Lessons Work

DataDriven combines four interview rounds (SQL, Python, Data Modeling, Pipeline Architecture) with adaptive difficulty and spaced repetition. Easy problems get harder as you improve. Weak concepts resurface until you master them. Your readiness score tracks progress across every topic interviewers test. Every lesson section ends with problems you solve by writing and running real code, not by picking multiple-choice answers.