**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 all_columns = new_metadata.columns.getAllPhysical();
    
    if (old_metadata.hasSortingKey())
    {
        
        
        Names new_primary_key_columns = new_primary_key.column_names;
        Names new_sorting_key_columns = new_sorting_key.column_names;
        ASTPtr added_key_column_expr_list = std::make_shared<ASTExpressionList>();
        const auto & old_sorting_key_columns = old_metadata.getSortingKeyColumns();
        for (size_t new_i = 0, old_i = 0; new_i < sorting_key_size; ++new_i)
        {
            if (old_i < old_sorting_key_columns.size())
            {
                if (new_sorting_key_columns[new_i] != old_sorting_key_columns[old_i])
                    added_key_column_expr_list->children.push_back(new_sorting_key.expression_list_ast->children[new_i]);
                else
                    ++old_i;
            }
            else
                added_key_column_expr_list->children.push_back(new_sorting_key.expression_list_ast->children[new_i]);
        }
        if (!added_key_column_expr_list->children.empty())
        {
            auto syntax = TreeRewriter(global_context).analyze(added_key_column_expr_list, all_columns);
            Names used_columns = syntax->requiredSourceColumns();
            NamesAndTypesList deleted_columns;
            NamesAndTypesList added_columns;