**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 (!metadata_snapshot->hasAnyTTL())
        return false;
    if (metadata_snapshot->hasRowsTTL())
    {
        if (isEmpty()) 
            return true;
        else if (ttl_infos.table_ttl.min == 0)
            return false;
    }
    for (const auto & [column, desc] : metadata_snapshot->getColumnTTLs())
    {
        
        if (!ttl_infos.columns_ttl.count(column) && getColumns().contains(column))
            return false;
    }
    for (const auto & move_desc : metadata_snapshot->getMoveTTLs())
    {
        
        if (!ttl_infos.moves_ttl.count(move_desc.result_column))
            return false;
    }
    for (const auto & group_by_desc : metadata_snapshot->getGroupByTTLs())
    {
        if (!ttl_infos.group_by_ttl.count(group_by_desc.result_column))
            return false;
    }
    for (const auto & rows_where_desc : metadata_snapshot->getRowsWhereTTLs())