apache/spark — pull request #3553 by maji2014 (2014-12-02 09:59:27+00:00)
Title: [spark-4691][shuffle]code optimization for judgement

In HashShuffleReader.scala and HashShuffleWriter.scala, no need to judge "dep.aggregator.isEmpty" again as this is judged by "dep.aggregator.isDefined"

In SortShuffleWriter.scala, "dep.aggregator.isEmpty" is better than "!dep.aggregator.isDefined" ?