mod_ruby, concurrency, IPC, and object caching.

This is more of a design question than anything, but, since mod_ruby allows 
for persistant objects within libraries, I thought I would ask: I'm writing 
Yet Another web framework/CMS, and was wondering what the best solution would 
be to avoid having disparate versions of an object (say, a DB row in a user 
table) being held in each of Apache's children. Solutions I've thought of:
1. Just erase the cache of any volatile data on startup. This goes against the 
premise of mod_ruby, which is to speed up CGI using a persistant namespace.
2. Contact the DB to see if an object with a certain ID has to be changed, 
before taking it as the current version. This seems okay, but would probably 
intoduce a few more DB queries per request than I'd wish.
3. Somehow maintain IPC between all the children, perhaps making one (possibly 
the first to serve a request) responsible for holding a table of such things.

I can't really think of how to do this; has anyone had any experience with 
something like this?