@HiveDecimalWritableVersionV1
  public int getScale() {
    return scale;
  }
Get a OldHiveDecimal instance from the writable and constraint it with maximum precision/scale.

@param maxPrecision maximum precision
@param maxScale maximum scale
@return OldHiveDecimal instance
storage-api/src/java/org/apache/hadoop/hive/serde2/io/HiveDecimalWritableV1.java