The Impala hiveserver2 implementation does not work with a DECIMAL result.

TTypeId::type TypeToHiveServer2Type(PrimitiveType t) {
  switch (t) {
    // Map NULL_TYPE to BOOLEAN, otherwise Hive's JDBC driver won't
    // work for queries like "SELECT NULL" (IMPALA-914).
    case TYPE_NULL: return TTypeId::BOOLEAN_TYPE;
    case TYPE_BOOLEAN: return TTypeId::BOOLEAN_TYPE;
    case TYPE_TINYINT: return TTypeId::TINYINT_TYPE;
    case TYPE_SMALLINT: return TTypeId::SMALLINT_TYPE;
    case TYPE_INT: return TTypeId::INT_TYPE;
    case TYPE_BIGINT: return TTypeId::BIGINT_TYPE;
    case TYPE_FLOAT: return TTypeId::FLOAT_TYPE;
    case TYPE_DOUBLE: return TTypeId::DOUBLE_TYPE;
    case TYPE_TIMESTAMP: return TTypeId::TIMESTAMP_TYPE;
    case TYPE_STRING: return TTypeId::STRING_TYPE;
    case TYPE_BINARY: return TTypeId::BINARY_TYPE;
    // TODO: update when hs2 has char(n)
    case TYPE_CHAR: return TTypeId::STRING_TYPE;
    default:
      // Hive only supports DECIMAL from 0.11 so we are not including it here.
      // HiveServer2 does not have a type for invalid, date and datetime.                  <-- This should be changed.
      DCHECK(false) << "bad TypeToTValueType() type: " << TypeToString(t);
      return TTypeId::STRING_TYPE;
  };
}