Hi there, Seems like Martin is right, the error seems to be that your object isn't serializable, and it indeed seems to be 'pickle' that's used for serialization (though I'm not 100% sure). The _io.TextIOWrapper you're trying to queue is probably a 'foreign' object, implemented in C or C++ or sth, and can therefore not be serialized. A solution would be to store your data in a simpler structure such as a dict or a simple object and add that to the queue instead.
Hope this helps. Cheers, Guido On Sat, Sep 3, 2016 at 9:02 PM, Martin Fitzpatrick < martin.fitzpatr...@gmail.com> wrote: > Hi Akshay > > It's a little difficult to understand what you're doing, but as a general > rule I would avoid using both multiprocessing and Qt threads (if only > because this is going to confuse things). The error you're receiving looks > like it is coming from the serialisation (pickle?) of the data in/out of > the task. > > For a problem like this I would suggest sticking with Qt threads and > implementing something via QRunnable/QThreadpool. I have a brief (draft) > writeup of this process on my site at: http://mfitzp.io/ > application-multithreading-with-pyqt/ ...will be finished up in a few > weeks. > > The approach is to create a QRunnable class that accepts a function to run > and passes notification/results out as signals. To start a job (e.g. > process a file) you would pass in your function, the filename and then > attach a listener to the 'result' signal. Once the task is run your data > will come back out via that. You can for example attach this signal to a > slot (python function) to update your GUI. > > If the plotting is causing a slow down, you might also want to try > PyQtGraph. > > Hope that helps > > Martin > > > > On 27 August 2016 at 10:16, Akshay Verma via Python-nl < > python-nl@python.org> wrote: > >> Hi all, >> >> After a lot of searching on the internet, I am looking for help from you >> guys. >> >> I am working on a Qt based GUI which takes in a stream of file paths >> coming from a separate process and reads those data file for >> post-processing and plotting. Since post-processing and plotting have >> become a bit involved, there is a request to improve the performance of the >> GUI. Currently the GUI takes in the input message with the path of the file >> and gives a SIGNAL to the Worker thread (Qt thread) to process the file. >> The processing results are saved in the object for reference and display >> within the GUI. Simple separation of the threads does not help a lot for >> intensive processing cases. I had to add a sleep of 1 sec to quick fix the >> GIL of Python and make the GUI responsive. To improve the solution, I >> thought of using Multiprocessing for the post-processing task. I am trying >> to add the task to queue and get back the result in a queue. When I >> implement this solution, I get '*TypeError: cannot serailize >> '_io.TextIOWrapper' object'* at the call of start() of the Process. >> >> What could be the cause of this error? Is there a better way to solve >> this issue? Any suggestions are welcome. >> >> Regards, Akshay Verma >> >> _______________________________________________ >> Python-nl mailing list >> Python-nl@python.org >> https://mail.python.org/mailman/listinfo/python-nl >> >> > > _______________________________________________ > Python-nl mailing list > Python-nl@python.org > https://mail.python.org/mailman/listinfo/python-nl > >
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