Optimization is a hierarchy: (1) **Reduce data scanned**—partition pruning, predicate pushdown, column pruning; biggest lever. (2) **Reduce shuffle**—broadcast small tables, avoid unnecessary repartitions, co-locate joins. (3) **Right-size parallelism**—spark.sql.shuffle.partitions ~2–4× cores; too many = task overhead; too few = underutilization. (4) **Avoid serialization hot paths**—use built-in functions over UDFs; UDFs break Catalyst and force row-by-row Python or slower Java....
The complete answer continues with detailed implementation patterns, architectural trade-offs, and production-grade considerations. It covers performance optimization strategies, common pitfalls to avoid, and real-world examples from companies like Fragma Data Systems, Presidio. The answer also includes follow-up discussion points that interviewers commonly explore.
Continue Reading the Full Answer
Unlock the complete expert answer with code examples, trade-offs, and pro tips - plus 1,863+ more.
Or upgrade to Platform Pro - $39
Engineers who used these answers got offers at
AmazonDatabricksSnowflakeGoogleMeta
According to DataEngPrep.tech, this is one of the most frequently asked Spark/Big Data interview questions, reported at 2 companies. DataEngPrep.tech maintains a curated database of 1,863+ real data engineering interview questions across 7 categories, verified by industry professionals.