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Home/Questions/SQL/Discuss a project where you significantly improved the performance of a data pipeline.

Discuss a project where you significantly improved the performance of a data pipeline.

SQLhard0.4 min readPremium

Frequency

Low

Asked at 1 company

Category

487

questions in SQL

Difficulty Split

130E|271M|86H

in this category

Total Bank

1,863

across 7 categories

Asked at these companies

Disney+ Hotstar

Key Concepts Tested

optimization partition spark

Expert AnswerPremium

73 wordsInterview-ready

**Situation**: Daily aggregation pipeline ran 4+ hours; blocking downstream. **Task**: Reduce to under 1 hour. **Action**: (1) Profiled with Spark UI—full table scans, large shuffles. (2) Partitioned source by date; partition pruning. (3) Replaced reduceByKey with aggregateByKey to reduce shuffle. (4) Broadcast small dimensions. (5) Tuned executor memory and parallelism. (6) Documented rationale; added monitoring. **Result**: Runtime under 35 minutes....

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 Disney+ Hotstar. The answer also includes follow-up discussion points that interviewers commonly explore.

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