I've received an inquiry about how I'm using SQLAlchemy under Twisted. I thought I'd provide the answer so that others can benefit from it as well:

http://foss.eepatents.com/pNetworkX/browser/trunk/pnetworkx/database.py

Note particularly the "transact" function, which is used as a decorator. Thanks to Valentino Volonghi (aka Dialtone) for the fine idea of using a decorator to set up a nonblocking transaction (using deferToThread) for whatever functions are so designated.

Here's a usage example, with various database-accessing methods that are decorated with "@transact":

http://foss.eepatents.com/pNetworkX/browser/trunk/pnetworkx/edges.py

Best regards, Ed Suominen