[Persistence-sig] Is threaded access to persistent objects in scope?

[Phillip J. Eby]

Does anybody have any use cases for multi-thread access to the same 
persistent object?

ZODB explicitly denies such thread-safety, making each thread responsible 
for maintaining a separate object cache, or otherwise synchronizing access, 
and thus avoiding locking issues and all the associated complexity.

I don't have any need to change this, personally; I'm happy staying as far 
away from threading issues as possible.  But does anybody have any 
*concrete* use cases where threaded access to the *same* object is a 
necessity?  By same, I mean the identical object pointer, rather than a 
copy of the object loaded specifically for that thread?  I haven't managed 
to come up with any use cases that wouldn't be better handled using message 
or event queues, or something like the Linda "tuplespace".

By the way, when I say "concrete", I mean that saying "oh, that sounds 
terrible for performance and language X doesn't do it that way" is not a 
"concrete" use case.  :)

Thanks!