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What insights can you gather from the DAG visualization in Spark UI?

Spark/Big Datahard0.4 min readPremium
Frequency
Low
Asked at 1 company
Category
452
questions in Spark/Big Data
Difficulty Split
88E|81M|283H
in this category
Total Bank
1,863
across 7 categories
Asked at these companies
PWC
Key Concepts Tested
optimizationspark
Expert AnswerPremium
81 wordsInterview-ready
**DAG Shows**: (1) Stage boundaries—wide vs. narrow. (2) Task count and parallelism. (3) Shuffle read/write. (4) Skew—task duration variance. (5) Cached RDDs (green). (6) Stage execution time. (7) Data flow. **Use For**: Bottlenecks (slowest stage), skew (one long task), unnecessary shuffles, optimization targets. **Why Critical**: Without DAG, optimization is guesswork....
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