public static ReduceWork getReduceWork(Configuration conf) {
    if (!conf.getBoolean(HAS_REDUCE_WORK, false)) {
      return null;
    }
    return (ReduceWork) getBaseWork(conf, REDUCE_PLAN_NAME);
  }
ReduceField:
KEY: record key
VALUE: record value
ql/src/java/org/apache/hadoop/hive/ql/exec/Utilities.java