apache/spark — pull request #1912 by davies (2014-08-13 00:31:59+00:00)
Title: [SPARK-1065] [PySpark] improve supporting for large broadcast

Passing large object by py4j is very slow (cost much memory), so pass broadcast objects via files (similar to parallelize()).

Add an option to keep object in driver (it's False by default) to save memory in driver.