Apache Spark processes data distributed across a cluster — Spark SQL for structured queries, DataFrame API for programmatic transformation (PySpark, Scala), Structured Streaming for real-time processing, MLlib for machine learning, and GraphX for graph analytics. Spark handles terabyte-scale data that single-machine tools (Pandas, SQL Server) cannot process.
Enterprise Spark typically runs on managed platforms: Databricks (most popular, Delta Lake integration, Unity Catalog), Microsoft Fabric (Spark notebooks within the unified platform), or cloud-native (Azure HDInsight, AWS EMR, GCP Dataproc). Spark optimization requires: partition strategy, shuffle management, broadcast joins, caching, and the cost/performance tuning that prevents $50K cloud bills from unoptimized Spark jobs.