**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

}
    /** It is important that obtaining new block number and adding that block to parts set is done atomically.
      * Otherwise there is race condition - merge of blocks could happen in interval that doesn't yet contain new part.
      */
    if (increment)
    {
        part_info.min_block = part_info.max_block = increment->get();
        part_info.mutation = 0; 
        part_name = part->getNewName(part_info);
    }
    else 
        part_name = part->name;
    LOG_TRACE(log, "Renaming temporary part {} to {}.", part->relative_path, part_name);
    auto it_duplicate = data_parts_by_info.find(part_info);
    if (it_duplicate != data_parts_by_info.end())
    {
        String message = "Part " + (*it_duplicate)->getNameWithState() + " already exists";
        if ((*it_duplicate)->checkState({DataPartState::Outdated, DataPartState::Deleting}))
            throw Exception(message + ", but it will be deleted soon", ErrorCodes::PART_IS_TEMPORARILY_LOCKED);
        throw Exception(message, ErrorCodes::DUPLICATE_DATA_PART);
    }
    DataPartPtr covering_part;
    DataPartsVector covered_parts = getActivePartsToReplace(part_info, part_name, covering_part, lock);
    DataPartsVector covered_parts_in_memory;
    if (covering_part)
    {
        LOG_WARNING(log, "Tried to add obsolete part {} covered by {}", part_name, covering_part->getNameWithState());
        return false;
    }