Apache Drill
Apache Drill is an open-source, schema-free SQL query engine for big data exploration. It enables interactive analysis of large-scale datasets across various data sources, including NoSQL databases, cloud storage, and Hadoop, without requiring upfront schema definitions or ETL processes. Drill supports ANSI SQL and provides low-latency queries through its distributed execution engine.
Developers should learn Apache Drill when they need to perform ad-hoc SQL queries on diverse, unstructured, or semi-structured data sources like JSON, Parquet, or HBase without pre-defining schemas. It's particularly useful in big data environments for data exploration, analytics, and integration tasks where flexibility and speed are critical, such as in data lakes or multi-source data analysis scenarios.