@Explain(vectorization = Vectorization.DETAIL, displayName = "dataColumnCount",
          explainLevels = { Level.DEFAULT, Level.EXTENDED })
      public int getDataColumnCount() {
        return vectorizedRowBatchCtx.getDataColumnCount();
      }
Returns a set containing all leaf operators from the operator tree in this work.
@return a set containing all leaf operators in this operator tree.
ql/src/java/org/apache/hadoop/hive/ql/plan/BaseWork.java