**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

{
    renamed = true;
    for (size_t i = 0; i < old_and_new_names.size(); ++i)
    {
        try
        {
            const auto & [old_name, new_name] = old_and_new_names[i];
            if (old_name.empty() || new_name.empty())
                throw DB::Exception("Empty part name. Most likely it's a bug.", ErrorCodes::INCORRECT_FILE_NAME);
            const auto & [path, disk] = old_part_name_to_path_and_disk[old_name];
            const auto full_path = path + source_dir; 
            disk->moveFile(full_path + old_name, full_path + new_name);
        }
        catch (...)
        {
            old_and_new_names.resize(i);
            LOG_WARNING(storage.log, "Cannot rename parts to perform operation on them: {}", getCurrentExceptionMessage(false));
            throw;
        }
    }
}
MergeTreeData::PartsTemporaryRename::~PartsTemporaryRename()