In Tuning Spark <https://spark.apache.org/docs/latest/tuning.html>, it says, Spark automatically includes Kryo serializers for the *many commonly-used core Scala classes* covered in the AllScalaRegistrar from the Twitter chill <https://github.com/twitter/chill> library.
I looked into the AllScalaRegistrar Javadoc, it only says, /** Registers all the scala (and java) serializers we have */ It seems to register only all scala and java primitive and collection classes, is that right? What about classes in Spark, do we need to register them ourselves, especially Row, GenericRow, MutableRow in Spark SQL?
