I haven't been following this discussion, but it sounds like there's the potential for SQL operations performed by LoginManager to interfere with other SQL operations such as logging uploaded files, in the case where the database system does not support nested (sub-) transactions. Correct?
No, but I'm really not familiar enough with the ZODB machinery and zope internals to tell do much more than wild guesses. The problem seems to be that the ZODB and things like Zcatalog know about subtransactions (you can disable them with the latter one), but some (the most) zope db-adapters don't. Now zope seems to use subtransactions internally and to expect the DAs to provide them also (commit_sub), but for now it seems to not completly clear when and why - see the thread "subtransactions". For file-uploads the threshold may be <~ 120kb, that is which bites people with loginmanager/postgres. The workaround from I cited should at least solve the zope-error, but I have no idea if it can hurt. The best thing would be to properly implement the missing methods in the DAs, I guess, unfortunately this is above my head for now. PS: the sybase DA seems to know about commit_sub cheers, oliver