Real Interview Questions

Why should you avoid using SELECT * in SQL queries?

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Sql Best Practices Performance

🟢 Easy Conceptual Junior 👤 Data Engineering 🏢 Xoriant Asked 2× Jul 2026

What is the query performance in terms of shift?

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Query Performance Database

🟡 Medium Conceptual Mid 👤 Data Engineering 🏢 Mphasis Asked 2× Mar 2026

What challenges did you face while implementing this custom scoring function, such as performance or accuracy issues?

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Elasticsearch Scoring Performance

🟡 Medium Conceptual Mid 👤 Data Engineering 🏢 IBM Asked 1× Sep 2026

What strategies did you implement to ensure that your deployed models performed well and to quickly identify and resolve any issues that arose?

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Model Deployment Performance Monitoring Issue Resolution

🟡 Medium Conceptual Mid 👤 Data Engineering 🏢 Brillio Asked 1× Sep 2026

After performing a transformation, you observe a distribution where 80% of the values fall into one category and the remaining 20% are evenly distributed across other categories. What does this tell you about the data and how would you interpret it?

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Data Transformation Data Distribution Statistical Analysis

🟡 Medium Conceptual Mid 👤 Data Engineering 🏢 Cognizant Asked 1× Sep 2026

Suppose your AWS Glue job takes a very long time (e.g., 20 minutes or more). How would you investigate and optimize its performance?

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Aws Glue Performance Etl

🟡 Medium Conceptual Mid 👤 Data Engineering 🏢 KPMG Asked 1× Sep 2026

You've implemented several end‑to‑end performance optimizations. Can you describe your experience and the services you used?

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Performance Optimization End-to-end Services

🟡 Medium Conceptual Mid 👤 Data Engineering 🏢 KPIT Technologies Asked 1× Sep 2026

You explained a dynamic business‑logic model node for role management in your recommendation engine. How do you implement and manage these ORM and data models in Python?

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Role Management Recommendation Engine Orm

🟡 Medium Conceptual Mid 👤 Data Engineering 🏢 Cognizant Asked 1× Sep 2026

You shared your implementation of SQLAlchemy ORM with Pydantic schemas and a repository pattern. Can you describe any performance optimization techniques you apply to ensure these ORM and more perform well under load?

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Sqlalchemy Pydantic Performance Optimization

🟡 Medium Conceptual Mid 👤 Data Engineering 🏢 Nihilent Asked 1× Sep 2026

Can you describe a solid business use case for using Kafka as a data source and AWS Glue for data transformation?

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Kafka Aws Glue Data Transformation Data Engineering

🟡 Medium Conceptual Junior 👤 Data Engineering 🏢 PwC Asked 1× Sep 2026

Describe the key functionalities of your data pipeline: the source system, the ingestion mechanism you use to bring data into cloud storage, the transformations and cleansing performed in the silver layer, the aggregation performed in the gold layer, and the consumers or users that consume the data. What is the business use case?

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Data Pipeline Data Lake Silver Layer Gold Layer Ingestion Transformation Business Use Case

🔴 Hard Conceptual Senior 👤 Data Engineering 🏢 Persistent Systems Asked 1× Sep 2026

Which schema design—star or snowflake—provides better query performance, and how does storage impact this choice?

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Star Schema Snowflake Schema Query Performance Data Modeling

🟡 Medium Conceptual Junior 👤 Data Engineering 🏢 eClerx Asked 1× Sep 2026

How do you enable the Performance option on the Basic tab of an Azure Data Lake Storage Gen2 account, and why is it important for analytical workloads?

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Azure Data Lake Storage Gen2 Performance Azure Storage

🟢 Easy Conceptual Junior 👤 Data Engineering 🏢 Capgemini Asked 1× Sep 2026

How would you design a system that receives a user query, uses a performance vector from a module, sends context to an AI component, and returns a global response?

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System Design Ai Performance Vector Context Management

🔴 Hard System Design Senior 👤 Data Engineering 🏢 Persistent Systems Asked 1× Sep 2026

If a downstream analyst says a dashboard is slow because a query over your Redshift or a thinner layer is scanning far too much data, how would you diagnose and optimize that end‑to‑end?

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Redshift Data Warehousing Performance Tuning

🟡 Medium Conceptual Mid 👤 Data Engineering 🏢 UST Asked 1× Jul 2026

What is the recommended method for including Lambda resources within a CloudFormation stack deployment?

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Aws Cloudformation Lambda

🟢 Easy Conceptual Fresher 👤 Data Engineering 🏢 Tech Mahindra Asked 1× Jul 2026

What is the primary use case of AWS CloudFormation?

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Aws Cloudformation Infrastructure As Code

🟢 Easy Conceptual Fresher 👤 Data Engineering 🏢 EY Asked 1× Jul 2026

How would you design a generic function that can handle such scenarios and be reused across platforms?

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Reusable Code Cross-platform Design Patterns

🟡 Medium Conceptual Mid 👤 Data Engineer 🏢 cognizant Asked 1× Jul 2026

What follow-up could reveal whether a candidate really understands throughput?

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Performance

🟡 Medium Conceptual Mid 👤 Software 🏢 Sonata Software Asked 1× Jun 2026

How would you explain the trade-off between correctness and performance when using network?

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Performance

🟢 Easy Conceptual Fresher 👤 Software 🏢 Xoriant Asked 1× Jun 2026