@Override
  public void transientInit(Configuration conf) throws HiveException {
    super.transientInit(conf);

    scratchBuffer = new byte[HiveDecimal.SCRATCH_BUFFER_LEN_TO_BYTES];
  }
To support vectorized cast of decimal to string.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/CastDecimalToString.java