```
SELECT *
FROM system.dictionaries
WHERE name LIKE 'XXXX%'

Row 1:
──────
database:                    default
name:                        XXXX_dict
uuid:                        00000000-0000-0000-0000-000000000000
status:                      LOADED
origin:                      default.XXXX_dict
type:                        Polygon
key:                         (Array(Array(Array(Array(Float64)))))
attribute.names:             ['name','id']
attribute.types:             ['String','String']
bytes_allocated:             0
query_count:                 0
hit_rate:                    1
element_count:               433731
load_factor:                 1
source:                      ClickHouse: default.XXXX
lifetime_min:                60
lifetime_max:                1800
loading_start_time:          2021-03-11 00:07:52
last_successful_update_time: 2021-03-11 00:08:24
loading_duration:            31.595
last_exception:
```
const DictionaryStructure & dict_struct,
                           const Poco::Util::AbstractConfiguration & config,
                           const std::string & config_prefix,
                           DictionarySourcePtr source_ptr)
{
    const String database = config.getString(config_prefix + ".database", "");
    const String name = config.getString(config_prefix + ".name");
    if (!dict_struct.key)
        throw Exception{"'key' is required for a polygon dictionary", ErrorCodes::BAD_ARGUMENTS};
    if (dict_struct.key->size() != 1)
        throw Exception{"The 'key' should consist of a single attribute for a polygon dictionary",
                        ErrorCodes::BAD_ARGUMENTS};
    IPolygonDictionary::InputType input_type;
    IPolygonDictionary::PointType point_type;
    const auto key_type = (*dict_struct.key)[0].type;
    const auto f64 = std::make_shared<DataTypeFloat64>();
    const auto multi_polygon_array = DataTypeArray(std::make_shared<DataTypeArray>(std::make_shared<DataTypeArray>(std::make_shared<DataTypeArray>(f64))));
    const auto multi_polygon_tuple = DataTypeArray(std::make_shared<DataTypeArray>(std::make_shared<DataTypeArray>(std::make_shared<DataTypeTuple>(std::vector<DataTypePtr>{f64, f64}))));