Hi buddies !
Our team is working on developing a  mulit data source sql engine use Calcite.But something confuse us,  why calcite generate Java code dynamicly on SQL query, it seen have performance issues in my opinion.
And building dynamic code object is very hard£¬the code is unreadable and hard to understood, futhermore we can not debug it.


i wander why it was designed like that, what advantage  of that .we search on internet, 
but nobody can realy explain it(may be we not goot at search, and poor english).
so anybody can tell me the history of this, or give us some article.


applogize for my poor english,  hope you know what i'm taking aboult. thank you very very very much !