Distributed Primitives

Concepts: paDistributedPrimitives

What They Want to Hear 'A transformation defines a new dataset from an existing one without executing anything. An action triggers execution and returns a result. Narrow transformations like filter and map process each partition independently. Wide transformations like groupBy and join require data to move between executors, which creates a shuffle.' That is the answer. Narrow = no data movement. Wide = shuffle. This distinction is the foundation of Spark performance.