public static boolean isAllNull(Object[] row) {
    if (row == null) {
      return true;
    }
    for (int i = 0; i < row.length - 1; i++) {
      if (row[i] != null) {
        return false;
      }
    }
    return true;
  }
this method checks whether the row returned by IUDFInputDataSet.nextRowInObjects() has all null
fields except the timestamp

@param row the returned row by calling {@link IUDFInputDataSet#nextRowInObjects()}
@return true if all row fields are null.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/transformation/dag/util/InputRowUtils.java