public static void setRepeatingColumn(VectorizedRowBatch batch, int column) {
    ColumnVector cv = batch.cols[column];
    cv.isRepeating = true;
  }
Iterates thru all the column vectors and sets repeating to
specified column.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/VectorizedBatchUtil.java