@HiveDecimalVersionV1
  public static HiveDecimalV1 create(BigInteger bi) {
    BigDecimal bd = normalize(new BigDecimal(bi), true);
    return bd == null ? null : new HiveDecimalV1(bd);
  }
Default precision/scale when system is not able to determine them, such as in case
 of a non-generic udf.
storage-api/src/java/org/apache/hadoop/hive/common/type/HiveDecimalV1.java