**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

{
    std::lock_guard lock(data.moving_parts_mutex);
    for (const auto & moving_part : parts_to_move)
    {
        
        if (!data.currently_moving_parts.count(moving_part.part))
            std::terminate();
        data.currently_moving_parts.erase(moving_part.part);
    }
}
std::optional<JobAndPool> MergeTreeData::getDataMovingJob()
{
    if (parts_mover.moves_blocker.isCancelled())
        return {};
    auto moving_tagger = selectPartsForMove();
    if (moving_tagger->parts_to_move.empty())
        return {};
    return JobAndPool{[this, moving_tagger] () mutable
    {
        return moveParts(moving_tagger);
    }, PoolType::MOVE};
}
bool MergeTreeData::areBackgroundMovesNeeded() const
{
    auto policy = getStoragePolicy();
    if (policy->getVolumes().size() > 1)
        return true;
    return policy->getVolumes().size() == 1 && policy->getVolumes()[0]->getDisks().size() > 1;
}
bool MergeTreeData::movePartsToSpace(const DataPartsVector & parts, SpacePtr space)