What is the medallion architecture?
Interviewer Expectations for this Question
01
Core Competency
Assesses fundamental understanding of Data Engineering conventions, runtime behavior, and memory/performance considerations.
02
Evaluation Criteria
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Comprehensive Model Answer
Verified Solution
The medallion architecture organizes a lakehouse into three refinement layers.
- Bronze (raw): data landed as-is from sources, append-only, with ingestion metadata. It is the source of truth and enables replay.
- Silver (validated): cleaned, deduplicated, conformed data, joined into entities and typed correctly. Analysts and engineers build on this layer.
- Gold (curated): business-level aggregates and marts optimized for BI, dashboards and machine learning.
Each layer is a table, often in Delta Lake or Iceberg, and transformations move data bronze to silver to gold. Benefits include clear ownership, incremental processing, and the ability to rebuild downstream layers from raw data. Costs come from storing multiple copies and maintaining transformation jobs. Keep schemas explicit with a catalog or data contract so consumers can rely on silver and gold tables.
Candidate Response Strategy & Interview Tips
- Start with a concise one-sentence summary: Deliver a direct, confident answer first before expanding into nuances.
- Demonstrate real-world trade-offs: Discuss where this approach excels and when you would avoid it in production systems.
- Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
- Prepare for interviewer follow-ups: Technical hiring panels frequently probe deeper into concurrency, backward compatibility, or alternative libraries.