Castlight Data Engineer Interview Questions
The questions to prepare for a Castlight Data Engineer interview. Questions from real interview reports rank first. Updated daily.
Explain how you improved a slow ETL pipeline on multi-terabyte data, including bottleneck analysis, tuning choices, and validation.
CastlightExplain how structured and unstructured data differ, and why that matters for pipeline design and downstream processing.
CastlightEvaluate when a pipeline should use stream processing versus scheduled batch based on latency, cost, complexity, and data quality needs.
CastlightDiscuss the data integration tools you have used and how they fit into ETL, orchestration, and data quality workflows.
CastlightTests practical data wrangling skills and correctness of preprocessing steps.
CastlightTests query analysis skills and practical optimization techniques.
CastlightTests understanding of scalable join strategies and performance considerations.
CastlightAggregate monthly sales by product category and use LAG to calculate month-over-month changes.
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Benjamin MooreCompute daily agent call KPIs and SLA using joins, aggregations, and window ranking in a contact center model.
ADPCount unique respondents by Python or R library and return the most commonly used libraries first.
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Tests ability to implement correct data aggregation logic over event data.
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