**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

{
    renameTo(getRelativePathForDetachedPart(prefix), true);
}
void IMergeTreeDataPart::makeCloneInDetached(const String & prefix, const StorageMetadataPtr & ) const
{
    String destination_path = storage.relative_data_path + getRelativePathForDetachedPart(prefix);
    
    localBackup(volume->getDisk(), getFullRelativePath(), destination_path, 0);
    volume->getDisk()->removeFileIfExists(destination_path + "/" + DELETE_ON_DESTROY_MARKER_FILE_NAME);
}
void IMergeTreeDataPart::makeCloneOnDisk(const DiskPtr & disk, const String & directory_name) const
{
    assertOnDisk();
    if (disk->getName() == volume->getDisk()->getName())
        throw Exception("Can not clone data part " + name + " to same disk " + volume->getDisk()->getName(), ErrorCodes::LOGICAL_ERROR);
    if (directory_name.empty())
        throw Exception("Can not clone data part " + name + " to empty directory.", ErrorCodes::LOGICAL_ERROR);
    String path_to_clone = storage.relative_data_path + directory_name + '/';
    if (disk->exists(path_to_clone + relative_path))
    {
        LOG_WARNING(storage.log, "Path " + fullPath(disk, path_to_clone + relative_path) + " already exists. Will remove it and clone again.");
        disk->removeRecursive(path_to_clone + relative_path + '/');
    }
    disk->createDirectories(path_to_clone);
    volume->getDisk()->copy(getFullRelativePath(), disk, path_to_clone);
    volume->getDisk()->removeFileIfExists(path_to_clone + '/' + DELETE_ON_DESTROY_MARKER_FILE_NAME);
}
void IMergeTreeDataPart::checkConsistencyBase() const