**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

ErrorCodes::TOO_MANY_PARTS,
            "Too many parts ({}). Parts cleaning are processing significantly slower than inserts",
            parts_count_in_partition);
    }
    if (k_inactive < 0 && parts_count_in_partition < settings->parts_to_delay_insert)
        return;
    const ssize_t k_active = ssize_t(parts_count_in_partition) - ssize_t(settings->parts_to_delay_insert);
    size_t max_k;
    size_t k;
    if (k_active > k_inactive)
    {
        max_k = settings->parts_to_throw_insert - settings->parts_to_delay_insert;
        k = k_active + 1;
    }
    else
    {
        max_k = settings->inactive_parts_to_throw_insert - settings->inactive_parts_to_delay_insert;
        k = k_inactive + 1;
    }
    const double delay_milliseconds = ::pow(settings->max_delay_to_insert * 1000, static_cast<double>(k) / max_k);
    ProfileEvents::increment(ProfileEvents::DelayedInserts);
    ProfileEvents::increment(ProfileEvents::DelayedInsertsMilliseconds, delay_milliseconds);
    CurrentMetrics::Increment metric_increment(CurrentMetrics::DelayedInserts);
    LOG_INFO(log, "Delaying inserting block by {} ms. because there are {} parts", delay_milliseconds, parts_count_in_partition);
    if (until)
        until->tryWait(delay_milliseconds);
    else
        std::this_thread::sleep_for(std::chrono::milliseconds(static_cast<size_t>(delay_milliseconds)));
}
MergeTreeData::DataPartPtr MergeTreeData::getActiveContainingPart(