public boolean isNullValue(int rowIndex, int columnIndex) {
      // valueIndex is converted index of values
      int valueIndex = getValueIndex(rowIndex);
      // validColumnIndex is converted index of columns in the Aligned TVList.
      int validColumnIndex = columnIndexList.get(columnIndex);
      if (validColumnIndex < 0 || validColumnIndex >= dataTypes.size()) {
        return true;
      }
      return outer.isNullValue(valueIndex, validColumnIndex);
    }
@param rowIndex index of sorted rows in the Aligned TVList.
@param columnIndex index of columnIndexList for the query.
@return boolean
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/utils/datastructure/AlignedTVList.java