public void setNullDataValue() {
    unscaledValue.update(1, 0, 0, 0);
  }
Vectorized execution uses the smallest possible positive non-zero
value to prevent possible later zero-divide exceptions. Set the field
to this value (1 in the internal unsigned 128 bit int).
common/src/java/org/apache/hadoop/hive/common/type/Decimal128.java