**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

{
            if (move_ttl_entry->destination_type == DataDestinationType::VOLUME)
                LOG_WARNING(log, "Would like to reserve space on volume '{}' by TTL rule of table '{}' but volume was not found or rule is not applicable at the moment",
                    move_ttl_entry->destination_name, log_name);
            else if (move_ttl_entry->destination_type == DataDestinationType::DISK)
                LOG_WARNING(log, "Would like to reserve space on disk '{}' by TTL rule of table '{}' but disk was not found or rule is not applicable at the moment",
                    move_ttl_entry->destination_name, log_name);
        }
        else
        {
            reservation = destination_ptr->reserve(expected_size);
            if (reservation)
                return reservation;
            else
                if (move_ttl_entry->destination_type == DataDestinationType::VOLUME)
                    LOG_WARNING(log, "Would like to reserve space on volume '{}' by TTL rule of table '{}' but there is not enough space",
                    move_ttl_entry->destination_name, log_name);
                else if (move_ttl_entry->destination_type == DataDestinationType::DISK)
                    LOG_WARNING(log, "Would like to reserve space on disk '{}' by TTL rule of table '{}' but there is not enough space",
                        move_ttl_entry->destination_name, log_name);
        }
    }
    
    if (selected_disk)
        reservation = selected_disk->reserve(expected_size);
    if (!reservation)
        reservation = getStoragePolicy()->reserve(expected_size, min_volume_index);
    return reservation;
}
SpacePtr MergeTreeData::getDestinationForMoveTTL(const TTLDescription & move_ttl, bool is_insert) const