PySpark DataFrames vs. Spark SQL: Which One Should You Use?

When building data pipelines in Apache Spark, one of the most common questions is: “Should I write this in Spark SQL or use the DataFrame API?” The short answer regarding performance is neither. Both are powered by the Catalyst Optimizer, meaning Spark converts both into the same optimized physical plan under the hood. However, from a Data Engineering perspective, the choice significantly impacts how you build, test, scale, and maintain your code. ...

February 26, 2026 · Arjun Sajeevan

Modernizing Architecture: Migrating from Hadoop to Data Lakehouse

For over a decade, Apache Hadoop was the backbone of Big Data, allowing companies to store massive datasets on commodity hardware. However, as data volume and variety exploded, the limitations of Hadoop became a major bottleneck for modern data teams. The Problem: Why Hadoop is Fading While Hadoop revolutionized distributed storage, it introduced several technical and operational challenges: The Small File Problem: Hadoop’s NameNode often struggles with millions of small files, leading to performance degradation and memory issues. Storage-Compute Coupling: In a traditional Hadoop cluster, if you need more processing power, you are forced to buy more storage disks as well. This leads to inefficient resource utilization and high costs. Operational Complexity: Managing a cluster—from NameNode health to YARN resource allocation—requires significant manual effort and specialized expertise. Lack of ACID Compliance: Ensuring data integrity during partial failures is difficult, often resulting in “dirty data” that requires manual cleanup. What is a Data Lakehouse? A Data Lakehouse is a hybrid architecture that combines the low-cost, flexible storage of a Data Lake with the performance, structure, and reliability of a Data Warehouse. ...

February 25, 2026 · Arjun Sajeevan