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PySpark / Core Concepts Interview Questions 2026

Published July 22, 2026 · Updated July 22, 2026

5 PySpark / Core Concepts interview questions from General and more. Real questions from Technical, System Design, and HR rounds.

5 questions
Companies: General

All PySpark / Core Concepts Questions

General Medium Technical round 2-5 years

Write a PySpark job that reads a CSV, computes the top 10 customers by total spend, and writes to Parquet.

↑ 18 upvotes · 46 engineers asked this · SDE2
General Medium Screening round 3-6 years

Explain the difference between persist() and cache() in Spark. When should you persist to disk?

↑ 17 upvotes · 45 engineers asked this · SDE2
General Hard Technical round 3-6 years

Your PySpark job fails with 'Caused by: java.lang.OutOfMemoryError: GC overhead limit exceeded' on the executor. What does this mean?

↑ 16 upvotes · 44 engineers asked this · SDE2
General Hard Screening round 4-7 years

What is Spark's DAG and how does the Catalyst optimizer improve query performance?

↑ 15 upvotes · 43 engineers asked this · SDE2
General Medium Screening round 2-5 years

Explain the difference between Spark transformations and actions. Why are transformations lazy?

↑ 14 upvotes · 42 engineers asked this · SDE2

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General PySpark / Core Concepts

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Frequently asked questions

Write a PySpark job that reads a CSV, computes the top 10 customers by total spend, and writes to Parquet.
Write a PySpark job that reads a CSV, computes the top 10 customers by total spend, and writes to Parquet.
Explain the difference between persist() and cache() in Spark. When should you persist to disk?
Explain the difference between persist() and cache() in Spark. When should you persist to disk?
Your PySpark job fails with 'Caused by: java.lang.OutOfMemoryError: GC overhead limit exceeded' on the executor. What does this mean?
Your PySpark job fails with 'Caused by: java.lang.OutOfMemoryError: GC overhead limit exceeded' on the executor. What does this mean?
What is Spark's DAG and how does the Catalyst optimizer improve query performance?
What is Spark's DAG and how does the Catalyst optimizer improve query performance?
Explain the difference between Spark transformations and actions. Why are transformations lazy?
Explain the difference between Spark transformations and actions. Why are transformations lazy?