Data engineering interview questions · hard
How do you ensure fault tolerance when processing large datasets in EMR?
How do you give permission to a notebook to other users in Databricks?
How do you help stakeholders query Delta Lake tables? What tools and approaches?
How do you identify skewed partitions in a dataset?
How do you implement incremental updates in a data lake using AWS services and Spark?
How do you implement row and column-level security in Databricks?
How do you initiate a DAG in Airflow?
How do you manage dependencies between tasks in a Cloud Composer DAG?
How do you manage memory allocation in Spark?
How do you manage schema changes in PySpark when processing data over time?
How do you monitor Spark jobs?
How do you monitor and debug Spark applications in production?
How do you move a Databricks notebook to higher environments?
How do you optimize a join operation in Spark for large datasets?
How do you optimize long-running PySpark scripts on EMR?
How do you reduce shuffle operations in Spark?
How do you resolve merge conflicts in Databricks notebooks?
How do you set up CI/CD for a PySpark ETL workflow?
How do you store streaming data in Delta Lake and handle schema evolution?
How do you use Spark UI to debug stages, tasks, and performance issues?
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The most common Spark interview topics are: the difference between RDDs and DataFrames, transformations vs actions, data skew and how to handle it, partition strategies, shuffle optimization, and the catalyst optimizer. Delta Lake and Structured Streaming are increasingly tested.
If you're targeting mid-to-senior roles at companies processing large datasets, yes. Spark/Big Data questions appear in most data engineering interviews at scale-up and enterprise companies. Even companies using other tools test Spark as a proxy for distributed systems knowledge.
Use Databricks Community Edition (free), Google Colab with PySpark, or local Docker setups. Focus on understanding concepts like partitioning, broadcast joins, and lazy evaluation. Most interview questions test conceptual understanding, not syntax.
Data skew handling and performance tuning are the most challenging areas. Interviewers ask how to diagnose skew in a Spark job, strategies to fix it (salting, repartitioning, broadcast joins), and how to read Spark UI for performance bottlenecks.