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POWhat problems will one see in using Python multiprocessing naively?
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  1. POWhat problems will one see in using Python multiprocessing naively?
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    copied!<p>We're considering re-factoring a large application with a complex GUI which is isolated in a decoupled fashion from the back-end, to use the new (Python 2.6) multiprocessing module. The GUI/backend interface uses Queues with Message objects exchanged in both directions.</p> <p>One thing I've just concluded (tentatively, but feel free to confirm it) is that "object identity" would not be preserved across the multiprocessing interface. Currently when our GUI publishes a Message to the back-end, it expects to get the same Message back with a result attached as an attribute. It uses object identity (<code>if received_msg is message_i_sent:</code>) to identify returning messages in some cases... and that seems likely not to work with multiprocessing.</p> <p>This question is to ask what "gotchas" like this you <em>have seen in actual use</em> or <em>can imagine one would encounter</em> in naively using the multiprocessing module, especially in refactoring an existing single-process application. Please specify whether your answer is based on actual experience. Bonus points for providing a usable workaround for the problem.</p> <p><strong>Edit:</strong> Although my intent with this question was to gather descriptions of problems <em>in general</em>, I think I made two mistakes: I made it community wiki from the start (which probably makes many people ignore it, as they won't get reputation points), and I included a too-specific example which -- while I appreciate the answers -- probably made many people miss the request for general responses. I'll probably re-word and re-ask this in a new question. For now I'm accepting one answer as best merely to close the question as far as it pertains to the specific example I included. Thanks to those who did answer!</p>
 

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