Re: [cx-oracle-users] passing a connection to a process?

[Amaury F. d'A. <ama...@gm...>]

2010/6/20 Chuck White <chu...@ch...>:
> Thanks for your response.
>
> Can you please post an example with the multiprocessing module. My understanding is that objects have to be picklable to spawn processes using multi-processing. Maybe I am missing something here.

The parameters have to be picklable, yes. But not the state of the
worker process...
In the following sample, the "connection" object would be a cx_Oracle
connection.
The important thing is that it's a global variable, so reused the next
time the worker process gets a new task.



connection = None

def worker(param):
    import time
    time.sleep(0.1)

    global connection
    if connection is None:
        print "%d Connect" % param
        connection = param
    else:
        print "%d Connected by %d" % (param, connection)
    return param + 10

if __name__ == '__main__':
    import multiprocessing
    pool = multiprocessing.Pool(processes=4)
    results = []
    for x in range(10):
        def callback(result, x=x):
            results.append((x, result))
        pool.apply_async(worker, [x], callback=callback)
    pool.close()
    pool.join()
    print "results", results



-- 
Amaury Forgeot d'Arc