Hi,
We are currently running a MM3 instance in "production" with a SQLite backend (at ulists.org). It was at first a test, but a lot of people have already started to use the service and now we are kind of stuck (but happy ;-) ).
First, I've seen a lot of DBLock issues in the logs and I think there also is a race condition happening with Held Messages that leads to subsequents 500 until you manually copy fake email files (If I'm correct, the held message file is deleted, then the SQL query is made but fails. The result is a system in an inconsistent state: there's a held message in DB, but no more on disk).
Second, I've tried to manually migrate to PostgreSQL but did not succeed because of a lot typing issues and differences between these two databases. Barry told me there's an SQLAlchemy port that is soon to be released, at least in alpha stage. Do you think it could help to achieve such a migration? I'm willing to help testing this new backend and, if someone can guide me with the MM stuff, write migration scripts.
Thanks and again, MM3 is really an awesome suite of software! :)
Guillaume