**Why DLT matters**: Declarative pipelines with built-in expectations, lineage, and orchestration—reduces boilerplate and improves reliability. **Ideal use case**: Medallion lakehouse with (1) declarative table definitions (what, not how); (2) expectations (VALIDATE, FAIL,...
This easy-level Spark/Big Data question appears frequently in data engineering interviews at companies like TCS. While less common, it tests deeper understanding that distinguishes strong candidates. Mastering the underlying concepts (etl, lakehouse, spark) will help you answer variations of this question confidently.
Start by clearly defining the core concept being asked about. Interviewers want to see that you understand the fundamentals before diving into implementation details. Structure your answer with a definition, then explain the practical application with a concise example.
Why DLT matters: Declarative pipelines with built-in expectations, lineage, and orchestration—reduces boilerplate and improves reliability. Ideal use case: Medallion lakehouse with (1) declarative table definitions (what, not how); (2) expectations (VALIDATE, FAIL, DROP); (3) CDC/SCD merge patterns; (4) incremental processing. Example: Bronze raw from Kafka → Silver deduped, validated (expect revenue >= 0) → Gold aggregated marts. Scalability trade-offs: DLT manages clusters; continuous pipelines for low latency; batch for cost. Cost implications: Built-in retries, auto-optimize—reduces ops cost; expect some platform overhead vs raw Spark. Best practice: Use for lakehouse ETL; enforce expectations; leverage built-in observability.
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Analyze My Answer — FreeAccording to DataEngPrep.tech, this is one of the most frequently asked Spark/Big Data interview questions, reported at 1 company. DataEngPrep.tech maintains a curated database of 1,863+ real data engineering interview questions across 7 categories, verified by industry professionals.