How to disable caching correctly in Sqlalchemy orm session?

Question

I have I thread in a daemon, that loops and performs the following query:

    try:
        newsletter = self.session.query(models.Newsletter).\\
                     


        

Answer 1

The problem in your code is due to database using REPEATABLE READ isolation level by default, so the query returns the same result unless you call commit() or rollback() (or use autocommit=True as Xeross suggested) or manually change isolation level.

Yes, SQLAlchemy does cache mapped objects (not query results!), because ORM pattern requires single object for each identity. By default SQLAlchemy uses weak identity map as cache, so object is automatically expunged from session when there is no references left to it. Note, that subsequent queries will update state of cached objects with new data, so no need to worry about this cache.