**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

bool shallParticipateInMerges(const StoragePolicyPtr & storage_policy) const;
    
    static UInt64 calculateTotalSizeOnDisk(const DiskPtr & disk_, const String & from);
    void calculateColumnsSizesOnDisk();
    String getRelativePathForPrefix(const String & prefix) const;
    
    
    NameSet getFileNamesWithoutChecksums() const;
    
    
    
    static inline constexpr auto DEFAULT_COMPRESSION_CODEC_FILE_NAME = "default_compression_codec.txt";
    static inline constexpr auto DELETE_ON_DESTROY_MARKER_FILE_NAME = "delete-on-destroy.txt";
    static inline constexpr auto UUID_FILE_NAME = "uuid.txt";