Working code does not equal "productive-level".
After being will-tested, "productive-level" code should think about things like::
- performance
- easy to observe and debug online
- easy to upgrade or bug fix for other people without docs
- easy to back up/restore
- easy to migrate
- easy to use (UX, automatic function, fail-safe and so on)
- better performance to growing data
- Solution for big traffic coming
- recovering automaticly