What do you see if you drop SqlAlchemy's logging to DEBUG? I think I had a similar problem a long time ago, migrating from 0.5 to 0.8. In my case, the issue was with the `Session` factory -- i was not properly creating/deleting `session` objects and they got recycled. So an error raised on one web page request , invalidated the transaction on a completely different web page request. i think there was a slight API change, couple with me doing things "the absolute wrong way" in 0.5.
the only thing I can think of, is tossing in a few `log.debug()` lines to trace your session objects and ensure that you're not accidentally recycling anything. i'd also make sure your current session/sessionmaker setup is in line with mike's current recommendations (which are in both the docs and faq) -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
