10+ Data Engineering Specialist Interview Questions and Answers

Creating data pipelines, processing requests, web crawling, scraping, and reading large CSV files in Python.

• Use tools like Apache Airflow or Luigi to create data pipelines

• Implement distributed computing frameworks like Apache Spark for processing millions of requests

• Utilize libraries like Scrapy or Beautiful Soup for web crawling and scraping

• Use pandas library in Python to efficiently read and process large CSV files

Query to identify and delete duplicate records in SQL

• Use a combination of SELECT and DELETE statements

• Identify duplicates using GROUP BY and HAVING clauses

• Delete duplicates based on a unique identifier or combination of columns

Handle incremental data by using tools like Apache Kafka for real-time data streaming and implementing CDC (Change Data Capture) for database updates.

• Utilize tools like Apache Kafka for real-time data streaming

• Implement CDC (Change Data Capture) for tracking database updates

• Use data pipelines to process and integrate incremental data

• Ensure data consistency and accuracy during incremental updates

The Scrum role involves daily activities in development and implementing an automation framework.

• As a Data Engineering Specialist, the Scrum role involves participating in daily stand-up meetings to discuss progress and obstacles.

• Daily activities may include coding, testing, debugging, and collaborating with team members to deliver high-quality software.

• Implementing an automation framework involves creating scripts or tools to automate repetitive tasks, improving efficiency a...read more

Various optimisation techniques were used in my project to improve performance and efficiency.

• Implemented indexing to speed up database queries

• Utilized caching to reduce redundant data retrieval

• Applied parallel processing to distribute workloads efficiently

• Optimized algorithms to reduce time complexity

• Used query optimization techniques to improve database performance

map() and reduce() are higher-order functions used in functional programming to transform and aggregate data respectively.

• map() applies a given function to each element of an array and returns a new array with the transformed values.

• reduce() applies a given function to the elements of an array in a cumulative way, reducing them to a single value.

Performance optimization in Spark involves tuning configurations, optimizing code, and utilizing best practices.

• Tune Spark configurations such as executor memory, number of executors, and shuffle partitions

• Optimize code by reducing unnecessary shuffling, using efficient transformations, and caching intermediate results

• Utilize best practices like using data partitioning, avoiding unnecessary data movements, and leveraging Spark UI for monitoring and debugging

• Consider using adv...read more

Transformations and actions are key concepts in Apache Spark for processing data.

• Transformations are operations that create a new RDD from an existing one, like map, filter, and reduceByKey.

• Actions are operations that trigger computation and return a result to the driver program, like count, collect, and saveAsTextFile.

Filters in DAX are used to manipulate data in Power BI reports. DAX calculations are used to create custom measures and columns.

• Filters in DAX include CALCULATE, FILTER, ALL, ALLEXCEPT, etc.

• DAX calculations are used to create custom measures like SUM, AVERAGE, etc.

• Examples: CALCULATE(SUM(Sales), FILTER(Products, Products[Category] = 'Electronics'))

Indexes in databases help improve query performance by allowing faster data retrieval.

• Types of indexes include clustered, non-clustered, unique, and composite indexes.

• Clustered indexes physically reorder the data in the table based on the index key.

• Non-clustered indexes create a separate structure that includes the indexed columns and a pointer to the actual data.

• Unique indexes ensure that no two rows have the same values in the indexed columns.

• Composite indexes are created o...read more