[Tim Peters]
Offhand it looks OK to me, but I don't have any of the code you're using.
[Maciej Wisniowski]
I think that it's not my code problem but rather something with DCOracle2 and to reproduce this error it is enough to call any 'DCOracle2 StoredProcedure' object simultaneously by a lot of users (50 is enough for my Zope (ZEO) to cause these errors).
Sorry, I'm not making myself clear: I don't have _any_ of the code you're using, including DCOracle2. I don't use it -- and I don't have time to try to figure out how to use it. But I know the code paths in ZODB on the way toward calling _p_resolveConflict, and if I did have the code you were using, this is what I'd do:
If you want to dig deeper, look into what happens inside lib/python/ZODB/ConflictResolution.py
I'll try to check this, thanks for the hint. :)
It's the only way you'll figure it out ;-)