**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

{
    auto lock = (acquired_lock) ? DataPartsLock() : lockParts();
    for (const auto & part : remove)
    {
        if (!data_parts_by_info.count(part->info))
            throw Exception("Part " + part->getNameWithState() + " not found in data_parts", ErrorCodes::LOGICAL_ERROR);
        part->assertState({DataPartState::PreCommitted, DataPartState::Committed, DataPartState::Outdated});
    }
    removePartsFromWorkingSet(remove, clear_without_timeout, lock);
}
MergeTreeData::DataPartsVector MergeTreeData::removePartsInRangeFromWorkingSet(const MergeTreePartInfo & drop_range, bool clear_without_timeout,
                                                                               bool skip_intersecting_parts, DataPartsLock & lock)
{
    DataPartsVector parts_to_remove;
    if (drop_range.min_block > drop_range.max_block)
        return parts_to_remove;
    auto partition_range = getDataPartsPartitionRange(drop_range.partition_id);
    for (const DataPartPtr & part : partition_range)
    {
        if (part->info.partition_id != drop_range.partition_id)
            throw Exception("Unexpected partition_id of part " + part->name + ". This is a bug.", ErrorCodes::LOGICAL_ERROR);
        if (part->info.min_block < drop_range.min_block)
        {
            if (drop_range.min_block <= part->info.max_block)
            {
                
                String error = "Unexpected merged part " + part->name + " intersecting drop range " + drop_range.getPartName();