A Dofn is a user defined function used with ParDo transform that gets invoked for each input element to emit zero or more elements. A bundle is a collection of elements (i.e records/messages) processed as a single unit of failure. The division of the collection into bundles is arbitrary and selected by the runner.

What is DoFn in Apache beam?

Annotation for declaring and dereferencing timers. Annotation on a splittable DoFn specifying that the DoFn performs an unbounded amount of work per input element, so applying it to a bounded PCollection will produce an unbounded PCollection .

What does Apache beam do?

Apache Beam is an open source, unified model for defining both batch and streaming data-parallel processing pipelines. … These tasks are useful for moving data between different storage media and data sources, transforming data into a more desirable format, or loading data onto a new system.