protected void checkExpansion() {
    if ((rowCount % ARRAY_SIZE) == 0) {
      expandValues();
      timestamps.add((long[]) getPrimitiveArraysByType(TSDataType.INT64));
    }
  }
Get whether value is null at the given position in TvList.

@param unsortedRowIndex value index
@return boolean
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/utils/datastructure/TVList.java