apache/spark — pull request #724 by jegonzal (2014-05-10 22:56:49+00:00)
Title: SPARK-1786: Edge Partition Serialization 

This appears to address the issue with edge partition serialization. The solution appears to be just registering the `PrimitiveKeyOpenHashMap`. However I noticed that we appear to have forked that code in GraphX but retained the same name (which is confusing). I also renamed our local copy to `GraphXPrimitiveKeyOpenHashMap`. We should consider dropping that and using the one in Spark if possible.