**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 (parts.empty())
        throw Exception("Nothing to move", ErrorCodes::NO_SUCH_DATA_PART);
    parts.erase(std::remove_if(parts.begin(), parts.end(), [&](auto part_ptr)
        {
            for (const auto & disk : volume->getDisks())
            {
                if (part_ptr->volume->getDisk()->getName() == disk->getName())
                {
                    return true;
                }
            }
            return false;
        }), parts.end());
    if (parts.empty())
    {
        String no_parts_to_move_message;
        if (moving_part)
            no_parts_to_move_message = "Part '" + partition_id + "' is already on volume '" + volume->getName() + "'";
        else
            no_parts_to_move_message = "All parts of partition '" + partition_id + "' are already on volume '" + volume->getName() + "'";
        throw Exception(no_parts_to_move_message, ErrorCodes::UNKNOWN_DISK);
    }
    if (!movePartsToSpace(parts, std::static_pointer_cast<Space>(volume)))
        throw Exception("Cannot move parts because moves are manually disabled", ErrorCodes::ABORTED);
}
void MergeTreeData::fetchPartition(const ASTPtr & , const StorageMetadataPtr & , const String & , const Context & )
{
    throw Exception(ErrorCodes::NOT_IMPLEMENTED, "FETCH PARTITION is not supported by storage {}", getName());
}
Pipe MergeTreeData::alterPartition(