apache/spark — pull request #3476 by maropu (2014-11-26 08:58:57+00:00)
Title: [SPARK-4620] Add unpersist in Graph and GraphImpl

Add an IF to uncache both vertices and edges of Graph/GraphImpl.
This IF is useful when iterative graph operations build a new graph in each iteration, and the vertices and edges of previous iterations are no longer needed for following iterations.