**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 (!getSettings()->remove_empty_parts)
        return;
    auto parts = getDataPartsVector();
    for (const auto & part : parts)
    {
        if (part->rows_count == 0)
        {
            ASTPtr literal = std::make_shared<ASTLiteral>(part->name);
            
            dropPartition(literal,  false,  true, global_context,  false);
        }
    }
}
void MergeTreeData::rename(const String & new_table_path, const StorageID & new_table_id)