**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 (!skip_intersecting_parts)
                    throw Exception(error, ErrorCodes::LOGICAL_ERROR);
                LOG_WARNING(log, error);
            }
            continue;
        }
        
        if (part->info.min_block > drop_range.max_block)
            break;
        if (part->info.min_block <= drop_range.max_block && drop_range.max_block < part->info.max_block)
        {
            
            String error = "Unexpected merged part " + part->name + " intersecting drop range " + drop_range.getPartName();
            if (!skip_intersecting_parts)
                throw Exception(error, ErrorCodes::LOGICAL_ERROR);
            LOG_WARNING(log, error);
            continue;
        }
        if (part->getState() != DataPartState::Deleting)
            parts_to_remove.emplace_back(part);
    }
    removePartsFromWorkingSet(parts_to_remove, clear_without_timeout, lock);
    return parts_to_remove;
}
void MergeTreeData::forgetPartAndMoveToDetached(const MergeTreeData::DataPartPtr & part_to_detach, const String & prefix, bool
restore_covered)
{
    LOG_INFO(log, "Renaming {} to {}{} and forgiving it.", part_to_detach->relative_path, prefix, part_to_detach->name);
    auto lock = lockParts();
    auto it_part = data_parts_by_info.find(part_to_detach->info);