**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 ((*curr_jt)->info.partition_id != (*prev_jt)->info.partition_id)
            {
                ++prev_jt;
                ++curr_jt;
                continue;
            }
            if ((*curr_jt)->contains(**prev_jt))
            {
                deactivate_part(prev_jt);
                prev_jt = curr_jt;
                ++curr_jt;
            }
            else if ((*prev_jt)->contains(**curr_jt))
            {
                auto next = std::next(curr_jt);
                deactivate_part(curr_jt);
                curr_jt = next;
            }
            else
            {
                ++prev_jt;
                ++curr_jt;
            }
        }
    }
    calculateColumnSizesImpl();
    LOG_DEBUG(log, "Loaded data parts ({} items)", data_parts_indexes.size());
}
static bool isOldPartDirectory(const DiskPtr & disk, const String & directory_path, time_t threshold)