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https://issues.apache.org/jira/browse/ARROW-10676?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17236670#comment-17236670
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BinbinLiang commented on ARROW-10676:
-------------------------------------
And the error does not occur, when I change 'multiprocessing.context.Process'
to 'multiprocess.context.Process' which use *dill* to serialize.
> [Python] pickle error occurs when using pyarrow._plasma.PlasmaClient with
> multiprocess on mac (python3.8.5)
> -----------------------------------------------------------------------------------------------------------
>
> Key: ARROW-10676
> URL: https://issues.apache.org/jira/browse/ARROW-10676
> Project: Apache Arrow
> Issue Type: Bug
> Components: Python
> Affects Versions: 0.17.1, 2.0.0
> Environment: OS: mac os catalina 10.15.6;
> Python version: python3.8.5;
> Reporter: BinbinLiang
> Priority: Major
>
> * The environment is：
> ** OS: mac os catalina 10.15.6;
> ** {color:#FF0000}Python version: python3.8.5;{color}
> * {color:#ff0000}It's ok, when use python3.7(3.7.2 or 3.7.3) or
> python3.6(3.6.8).
> The error occurs only in python3.8.5.{color}
> * When I use 'pyarrow._plasma.PlasmaClient' in the
> 'multiprocessing.context.Process', the error occurs.
> ** First, I have a subclass of 'multiprocessing.context.Process', named
> Executor;
> The defined code like this: 'class Executor(Process):' .
> ** And then, I create a 'PlasmaClient' object in the '__init__' function of
> 'class Executor' .
> ** Finally, I new a 'Executor' object, and call the 'start()' function.
> * The detail informations of traceback are as follows:
> Traceback (most recent call last):
> File
> "/Users/liangbinbin/PycharmProjects/waimai_data_cubeinsight/python/taf/server/taf_server.py",
> line 100, in LaunchExecutor
> executor.start()
> File
> "/Users/liangbinbin/Applications/anaconda3/envs/python3_8/lib/python3.8/multiprocessing/process.py",
> line 121, in start
> self._popen = self._Popen(self)
> File
> "/Users/liangbinbin/Applications/anaconda3/envs/python3_8/lib/python3.8/multiprocessing/context.py",
> line 224, in _Popen
> return _default_context.get_context().Process._Popen(process_obj)
> File
> "/Users/liangbinbin/Applications/anaconda3/envs/python3_8/lib/python3.8/multiprocessing/context.py",
> line 284, in _Popen
> return Popen(process_obj)
> File
> "/Users/liangbinbin/Applications/anaconda3/envs/python3_8/lib/python3.8/multiprocessing/popen_spawn_posix.py",
> line 32, in __init__
> super().__init__(process_obj)
> File
> "/Users/liangbinbin/Applications/anaconda3/envs/python3_8/lib/python3.8/multiprocessing/popen_fork.py",
> line 19, in __init__
> self._launch(process_obj)
> File
> "/Users/liangbinbin/Applications/anaconda3/envs/python3_8/lib/python3.8/multiprocessing/popen_spawn_posix.py",
> line 47, in _launch
> reduction.dump(process_obj, fp)
> File
> {color:#FF0000}"/Users/liangbinbin/Applications/anaconda3/envs/python3_8/lib/python3.8/multiprocessing/reduction.py",
> line 60, in dump{color}
> {color:#FF0000}ForkingPickler(file, protocol).dump(obj){color}
> {color:#FF0000}File "stringsource", line 2, in
> *pyarrow._plasma.PlasmaClient.__reduce_cython__*{color}
> TypeError: no default __reduce__ due to non-trivial __cinit__
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