Uneven load is one of problems in distributed data processing. How to ensure that the any of nodes becomes a straggler ? Apache Beam proposes a solution for that in the form of fanout mechanism applicable in Combine transform.
As every library, Spark has methods than are used more often than the others. As often used methods we could certainly define map or filter. In the other side of less popular transformations we could place, among others, tree-like methods that will be presented in this post.