I would use something like typed racket or haskell for all the critical parts to increase safety. Then I would check the performance bottlenecks and rewrite them in C if needed.
Then I would use a more programmer friendly language on top of that. Something like Scheme, Ruby, Python and the like.
Stratified design, basically.
> I would use something like typed racket or haskell for all the critical parts to increase safety
I am not sure about Haskell, but, from my limited experience, Erlang runs at levels very close to C (my C, at least)
In terms of speed? Erlang's not even in the ballpark that C is in. I'm pretty sure Haskell significantly outperforms Erlang as well.
http://shootout.alioth.debian.org/u32/which-programming-lang...
What I had in mind was that for anyone who is technically capable of maintaining the core Oracle DB code base, there are more interesting and rewarding things they could be doing instead.