Mod_ruby questions

I’m looking into mod_ruby because the Apache+Mongrel combination that
I’m currently using seems to have big overhead and somewhat slow, but I
don’t quite understand a few things:

  1. If I move from the Apache+Mongrel combination to Apache+mod_ruby,
    will my overhead decrease? Significantly? (definitions are up for

  2. Will I have to change any Ruby code?

  3. In regards to the “shared interpreter” problem: I run multiple Rails
    apps on the same server; however, does this mean if I define constant A
    in one app and then also in another app I will get errors and/or it will
    be overriden?

Let me know if I need to clarify any question. Also, feel free to voice
your opinions on the “best” Rails webserver setup (for shared hosting