I'm confused about what you said about the underlined connection: I am creating 2 different engines. Why would both share the same connection?
FYI - I just tried without zope.sqlalchemy and got a slightly different result: My concurrent transactions are no longer failing with TransactionRollbackError "concurrent update". I suspect the isolation level 'REPEATABLE READ' is not been set. The intermediate checkpoint 'did something' doesn't get persisted either (same as before) but I cannot verify the failure checkpoint as the TransactionRollbackError is not happening. Will need to force a failure and see. -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- 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 https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
