one issue is that youre creating an endless number of threads using a
"while True"...a python interpreter (and your computer) can only
handle a limited number of simultaneous threads.
the other is that the session object is not threadsafe. youll need
to use a distinct session per each thread.
the "threadlocal" mod and more generally the "sessioncontext" module
can help with this task; but those should not be used unless you
understand what theyre doing.
in all cases, with or without one of those helper extensions, you
dont want to have the "create_session" step at the module level like
that.
On Sep 18, 2006, at 5:39 PM, Viktor wrote:
> Probably I'm missing something about SQLAlchemy used in threading
> environment, but I can't make this code work whatever I do:
>
>
> import sqlalchemy as sa
> import random
>
> db = sa.create_engine('postgres://alef:[EMAIL PROTECTED]:5432/test')
> metadata = sa.BoundMetaData(db)
>
> session = sa.create_session(bind_to=db)
>
> customer_table = sa.Table('customer', metadata,
> sa.Column('customerid', sa.Integer, primary_key=True),
> sa.Column('name', sa.String()),
> sa.Column('age', sa.Integer))
>
>
> class Customer(object):
> pass
>
>
> Customer._mapper = sa.mapper(Customer, customer_table)
> Customer.objects = session.query(Customer)
>
>
>
> def worker():
> c = Customer()
> c.name = str(random.randint(0, 100))
> c.age = random.randint(0, 100)
>
> session.save(c)
> session.flush()
>
> c = Customer.objects.select_by(name=str(random.randint(0, 100)),
> age=random.randint(0, 100))
> print c
>
> if __name__ == '__main__':
> while True:
> t = threading.Thread(target=worker)
> t.setDaemon(1)
> t.start()
>
>
> I tried adding threadlocks, using threadlocal, but whatever I use,
> I get
> some kind of exception...
>
> Thanks in advance.
>
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