I'm using sqlalchemy with sqlite engine (development server) and just discovered that after update query, queries in next web-requests return outdated data set (that depends on fact which thread is used for the request, as I understand there is a pool of threads). 

I'm using `scoped_session` and the other recommended stuff from docs (`DBSession = scoped_session(sessionmaker(extension=ZopeTransactionExtension()))`).

Here is the example of web requests and what's executed there.

```
request-1:thread-1: SELECT * FROM table WHERE id=1 -> (id:1, data:1)
request-2:thread-2: UPDATE table SET data=2 WHERE id=1; COMMIT
request-3:thread-1: SELECT * FROM table WHERE id=1 -> (id:1, data:1) // STILL data:1 !
request-4:thread-4: SELECT * FROM table WHERE id=1 -> (id:1, data:2) // NEW DATA!     
request-5:thread-1: SELECT * FROM table WHERE id=1 -> (id:1, data:1) // AND AGAIN OLD DATA!

```

What is this? How can I avoid this behaviour? In the example above all web requests are executed in consecutive order, so SQL-queries do not intersect.