public Multimap<Integer, InputSplit> generateGroupedSplits(JobConf jobConf,
                                                                    Configuration conf,
                                                                    InputSplit[] splits,
                                                                    float waves, int availableSlots,
                                                                    SplitLocationProvider locationProvider)
      throws Exception {
    return generateGroupedSplits(jobConf, conf, splits, waves, availableSlots, null, true, locationProvider);
  }
Generate groups of splits, separated by schema evolution boundaries
ql/src/java/org/apache/hadoop/hive/ql/exec/tez/SplitGrouper.java