public static MapredWork getMapRedWork(ParseContext parseCtx) {
    MapredWork work = getMapRedWorkFromConf(parseCtx.getConf());
    work.getMapWork().setNameToSplitSample(parseCtx.getNameToSplitSample());
    return work;
  }
create a new plan and return.

@return the new plan
ql/src/java/org/apache/hadoop/hive/ql/optimizer/GenMapRedUtils.java