Philippe Marschall wrote:
>> (Alternatives that are indexed by integers might also work well, e.g. a flat
>> WeakValueDictionary that used a WeakArray for its values).
> 
> Lord no, please no more Weak* collections. That was one of the major
> performance fixes we did in Seaside, kicking Weak* collections. They
> don't scale, they kill you in production.

It's finalization that kills you, not weak collections per se. If it 
were then symbol management should cause the same issues. For the case 
in question you could shrink the character table on system startup / 
shutdown which would avoid the finalization issues.

Cheers,
   - Andreas