He who performs not practical work nor makes experiments will never attain to the least degree of mastery.
—Jabir ibn Hayyan (Geber)
Spark Streaming applications by design are stateless and side-effect free: running the same application an infinite number of times results in the same behavior and output. Similar to functional programming, this simplifies debugging and reasoning about the state of a program, because input and output paths are deterministic. Although side-effect-free applications have many advantages, in distributed systems side effects cannot be completely avoided, especially when interfacing ...
