**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

{
    const auto settings = getSettings();
    const size_t parts_count_in_total = getPartsCount();
    if (parts_count_in_total >= settings->max_parts_in_total)
    {
        ProfileEvents::increment(ProfileEvents::RejectedInserts);
        throw Exception("Too many parts (" + toString(parts_count_in_total) + ") in all partitions in total. This indicates wrong choice of partition key. The threshold can be modified with 'max_parts_in_total' setting in <merge_tree> element in config.xml or with per-table setting.", ErrorCodes::TOO_MANY_PARTS);
    }
    size_t parts_count_in_partition = getMaxPartsCountForPartition();
    ssize_t k_inactive = -1;
    if (settings->inactive_parts_to_throw_insert > 0 || settings->inactive_parts_to_delay_insert > 0)
    {
        size_t inactive_parts_count_in_partition = getMaxInactivePartsCountForPartition();
        if (inactive_parts_count_in_partition >= settings->inactive_parts_to_throw_insert)
        {
            ProfileEvents::increment(ProfileEvents::RejectedInserts);
            throw Exception(
                ErrorCodes::TOO_MANY_PARTS,
                "Too many inactive parts ({}). Parts cleaning are processing significantly slower than inserts",
                inactive_parts_count_in_partition);
        }
        k_inactive = ssize_t(inactive_parts_count_in_partition) - ssize_t(settings->inactive_parts_to_delay_insert);
    }
    if (parts_count_in_partition >= settings->parts_to_throw_insert)
    {
        ProfileEvents::increment(ProfileEvents::RejectedInserts);
        throw Exception(