**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

{
    throw Exception("Method 'checkConsistency' is not implemented for part with type " + getType().toString(), ErrorCodes::NOT_IMPLEMENTED);
}
void IMergeTreeDataPart::calculateColumnsSizesOnDisk()
{
    if (getColumns().empty() || checksums.empty())
        throw Exception("Cannot calculate columns sizes when columns or checksums are not initialized", ErrorCodes::LOGICAL_ERROR);
    calculateEachColumnSizes(columns_sizes, total_columns_size);
}
ColumnSize IMergeTreeDataPart::getColumnSize(const String & column_name, const IDataType & ) const
{
    
    auto it = columns_sizes.find(column_name);
    if (it != columns_sizes.end())
        return it->second;
    return ColumnSize{};
}
void IMergeTreeDataPart::accumulateColumnSizes(ColumnToSize & column_to_size) const
{
    for (const auto & [column_name, size] : columns_sizes)
        column_to_size[column_name] = size.data_compressed;
}
bool IMergeTreeDataPart::checkAllTTLCalculated(const StorageMetadataPtr & metadata_snapshot) const