New submission from Andrii V. Mishkovskyi <[EMAIL PROTECTED]>:
`multiprocessing` hangs, when `multiprocessing.Pool` methods `map`,
`imap`, `imap_unordered`, `apply`, `apply_async`, `map_async` are called.
Here is an example:
Python 3.0b1+ (py3k:64686M, Jul 3 2008, 13:06:13)
[GCC 4.2.3 (Ubuntu 4.2.3-2ubuntu7)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from multiprocessing import Pool
>>> Pool(processes=4).imap(lambda x: x, range(10))
<multiprocessing.pool.IMapIterator object at 0x83bcc8c>
>>> Pool(processes=4).map(lambda x: x, range(10))
Exception in thread Thread-13:
Traceback (most recent call last):
File "/usr/local/lib/python3.0/threading.py", line 492, in
_bootstrap_inner
self.run()
File "/usr/local/lib/python3.0/threading.py", line 447, in run
self._target(*self._args, **self._kwargs)
File "/usr/local/lib/python3.0/multiprocessing/pool.py", line 225, in
_handle_tasks
put(task)
File "/usr/local/lib/python3.0/pickle.py", line 1319, in dumps
Pickler(f, protocol).dump(obj)
File "/usr/local/lib/python3.0/multiprocessing/util.py", line 311, in
_reduce_method
if m.__self__ is None:
AttributeError: 'function' object has no attribute '__self__'
Process PoolWorker-28:
Traceback (most recent call last):
File "/usr/local/lib/python3.0/multiprocessing/process.py", line 232,
in _bootstrap
self.run()
File "/usr/local/lib/python3.0/multiprocessing/process.py", line 88,
in run
self._target(*self._args, **self._kwargs)
File "/usr/local/lib/python3.0/multiprocessing/pool.py", line 57, in
worker
task = get()
File "/usr/local/lib/python3.0/multiprocessing/queues.py", line 337,
in get
Process PoolWorker-27:
Traceback (most recent call last):
File "/usr/local/lib/python3.0/multiprocessing/process.py", line 232,
in _bootstrap
self.run()
File "/usr/local/lib/python3.0/multiprocessing/process.py", line 88,
in run
self._target(*self._args, **self._kwargs)
File "/usr/local/lib/python3.0/multiprocessing/pool.py", line 57, in
worker
task = get()
File "/usr/local/lib/python3.0/multiprocessing/queues.py", line 337,
in get
Process PoolWorker-26:
Traceback (most recent call last):
File "/usr/local/lib/python3.0/multiprocessing/process.py", line 232,
in _bootstrap
Process PoolWorker-25:
Traceback (most recent call last):
File "/usr/local/lib/python3.0/multiprocessing/process.py", line 232,
in _bootstrap
self.run()
File "/usr/local/lib/python3.0/multiprocessing/process.py", line 88,
in run
self._target(*self._args, **self._kwargs)
File "/usr/local/lib/python3.0/multiprocessing/pool.py", line 57, in
worker
task = get()
File "/usr/local/lib/python3.0/multiprocessing/queues.py", line 337,
in get
self.run()
File "/usr/local/lib/python3.0/multiprocessing/process.py", line 88,
in run
self._target(*self._args, **self._kwargs)
File "/usr/local/lib/python3.0/multiprocessing/pool.py", line 57, in
worker
task = get()
File "/usr/local/lib/python3.0/multiprocessing/queues.py", line 339,
in get
return recv()
KeyboardInterrupt
racquire()
KeyboardInterrupt
racquire()
KeyboardInterrupt
racquire()
KeyboardInterrupt
Terminated
The same happens on latest trunk of Python 2.6.
Note, `map` and `apply` methods hang Python interpreter completely, so I
have to use `kill` utility to exit Python.
----------
components: Library (Lib)
messages: 69207
nosy: jnoller, mishok13, roudkerk
severity: normal
status: open
title: Multiprocessing hangs when multiprocessing.Pool methods are called
type: crash
versions: Python 2.6, Python 3.0
_______________________________________
Python tracker <[EMAIL PROTECTED]>
<http://bugs.python.org/issue3272>
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