**Describe the bug**

I have a table like:

```
CREATE TABLE test (
    time DateTime64(3)
    ...
) ENGINE = MergeTree()
PARTITION BY toStartOfInterval(time, INTERVAL 1 HOUR)
...
```

But when I search in `system.parts` it does not appear to have the `min/max` columns appropriately set?

```
partition:                             2020-06-01 01:00:00
min_date:                              1970-01-01
max_date:                              1970-01-01
min_time:                              1970-01-01 00:00:00
max_time:                              1970-01-01 00:00:00
```

I assume that if these were correctly set, doing a `select toStartOfInterval(time, interval 1 day), count()` type query would be pretty instant rather than trying to scan everything? I am guessing this is due to the `DateTime64` type in use?

Clickhouse 20.11.3.3

: StorageSystemPartsBase(table_id_,
    {
        {"partition",                                   std::make_shared<DataTypeString>()},
        {"name",                                        std::make_shared<DataTypeString>()},
        {"uuid",                                        std::make_shared<DataTypeUUID>()},
        {"part_type",                                   std::make_shared<DataTypeString>()},
        {"active",                                      std::make_shared<DataTypeUInt8>()},
        {"marks",                                       std::make_shared<DataTypeUInt64>()},
        {"rows",                                        std::make_shared<DataTypeUInt64>()},
        {"bytes_on_disk",                               std::make_shared<DataTypeUInt64>()},
        {"data_compressed_bytes",                       std::make_shared<DataTypeUInt64>()},
        {"data_uncompressed_bytes",                     std::make_shared<DataTypeUInt64>()},
        {"marks_bytes",                                 std::make_shared<DataTypeUInt64>()},
        {"modification_time",                           std::make_shared<DataTypeDateTime>()},
        {"remove_time",                                 std::make_shared<DataTypeDateTime>()},
        {"refcount",                                    std::make_shared<DataTypeUInt32>()},
        {"min_date",                                    std::make_shared<DataTypeDate>()},
        {"max_date",                                    std::make_shared<DataTypeDate>()},
        {"min_time",                                    std::make_shared<DataTypeDateTime>()},
        {"max_time",                                    std::make_shared<DataTypeDateTime>()},
        {"partition_id",                                std::make_shared<DataTypeString>()},
        {"min_block_number",                            std::make_shared<DataTypeInt64>()},
        {"max_block_number",                            std::make_shared<DataTypeInt64>()},
        {"level",                                       std::make_shared<DataTypeUInt32>()},
        {"data_version",                                std::make_shared<DataTypeUInt64>()},
        {"primary_key_bytes_in_memory",                 std::make_shared<DataTypeUInt64>()},