protected void setupMapWork(MapWork mapWork, GenTezProcContext context,
      PrunedPartitionList partitions, TableScanOperator root,
      String alias) throws SemanticException {
    // All the setup is done in GenMapRedUtils
    GenMapRedUtils.setMapWork(mapWork, context.parseContext,
        context.inputs, partitions, root, alias, context.conf, false);
  }
Checks if there is a Bucket Map Join (BMJ) following a hierarchy:
ReduceSinkOperator (RS) -> ReduceSinkOperator (RS) -> MapJoinOperator (MJ).
Ensures at most **two** RSOs before MJ.
ql/src/java/org/apache/hadoop/hive/ql/parse/GenTezUtils.java