Magnus Hult ha scritto:
Thanks for your swift reply!
On 6/13/07, Manlio Perillo <[EMAIL PROTECTED]> wrote:
Magnus Hult ha scritto:
> When executing the following program, changes in the database (other
> than those made by this program) aren't visible until it is restarted,
> due to some form of SQLAlchemy caching:
Are you using PostgreSQL?
Yes, I am. With psycopg2.
[...]
The solution is: make sure to add a commit after every select.
It doesn't seem to help though. In fact, the following little program
t = objectstore.create_transaction()
m = model.MyModel.get(1)
print m.some_column
t.commit()
sys.stdin.readline()
t = objectstore.create_transaction()
m = model.MyModel.get(1)
print m.some_column
t.commit()
only seems to execute one select statement. The other result seems to
be taken from the cache. If this is the case, then this question would
rather belong in an SQLAlchemy mailing list, I guess.
The problem can be this:
http://www.sqlalchemy.org/docs/documentation.html#unitofwork_identitymap
After the first "select" you do not reset the Unif Of Work.
In my queries I always do:
def _sessionTransaction(self, callable_, *args, **kwargs):
from sqlalchemy import orm
conn = self.contextual_connect()
sess = orm.create_session(bind_to=conn) # This cannot fail
try:
trans = sess.create_transaction()
try:
ret = callable_(conn, sess, *args, **kwargs)
trans.commit()
return ret
except:
trans.rollback()
raise
finally:
sess.close() # This cannot fail
conn.close()
I create and close a new session object for every request.
You can give a look at my nadbapi:
http://developer.berlios.de/projects/nadbapi/
Regards Manlio Perillo
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