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Created on 2016-01-22 15:24 by mzamazal, last changed 2022-04-11 14:58 by admin.
| Files | ||||
|---|---|---|---|---|
| File name | Uploaded | Description | Edit | |
| bug.py | mzamazal, 2016-01-22 15:24 | |||
| bug3.py | mzamazal, 2016-01-25 08:22 | |||
| Pull Requests | |||
|---|---|---|---|
| URL | Status | Linked | Edit |
| PR 13986 | open | orivej, 2019-06-11 20:32 | |
| Messages (6) | |||
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| msg258816 - (view) | Author: Milan Zamazal (mzamazal) | Date: 2016-01-22 15:24 | |
When calling multiprocessing.managers.BaseManager repeatedly from a client, each time from a new thread, new entry with (already existent) multiprocessing.util.ForkAwareLocal instance is inserted as a value into multiprocessing.util._afterfork_registry dictionary on each of the calls. So the dictionary grows on each client call and may grow so indefinitely, causing memory leak if nothing else. The attached file demonstrates the problem (Python 2.7 version, it's reproducible on 3.4 as well after 2->3 adjustments). Just run it and look at the output. The printed dictionary contains 10 entries holding the same ForkAwareLocal instance although there should be probably just one such entry there. |
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| msg258850 - (view) | Author: Terry J. Reedy (terry.reedy) *  |
Date: 2016-01-23 00:27 | |
Please post your 3.x version. 3.4 only gets security patches now. |
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| msg258896 - (view) | Author: Milan Zamazal (mzamazal) | Date: 2016-01-25 08:22 | |
Python 3.x version attached. |
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| msg345473 - (view) | Author: Jeroen Demeyer (jdemeyer) *  |
Date: 2019-06-13 08:20 | |
Why is it that __init__ is called multiple times? I'm just wondering if we could somehow ensure that __init__ is called only once. |
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| msg345524 - (view) | Author: Terry J. Reedy (terry.reedy) * |
Date: 2019-06-13 15:47 | |
With master and Windows 10, the output looks like (0, 61333912, <function ForkAwareThreadLock._reset at 0x03A783F0>): <multiprocessing.util.ForkAwareThreadLock object at 0x03A7E198> (1, 63524512, <function ForkAwareLocal.__init__.<locals>.<lambda> at 0x03CA2940>): <multiprocessing.util.ForkAwareLocal object at 0x03C94EA0> (2, 60787504, <function ProcessLocalSet.__init__.<locals>.<lambda> at 0x03CA2760>): ProcessLocalSet() (5, 63524512, <function ForkAwareLocal.__init__.<locals>.<lambda> at 0x03CA2C60>): <multiprocessing.util.ForkAwareLocal object at 0x03C94EA0> ... <8 more lines like the two with ForkAwareLocal.__init__....> I am not familiar with multiprocessing Managers and the doc is not completely clear to me. Does bug3.py only run in one process or does it result in multiple processes? If the latter, I expect it would need an "if __name__ == '__main__':" clause, at least on Windows. (Milan, I should have asked what OS you used, as mp has OS-specific behaviors.) (https://docs.python.org/3/library/multiprocessing.html#the-spawn-and-forkserver-start-methods, Safe importing of main module) |
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| msg345561 - (view) | Author: Milan Zamazal (mzamazal) | Date: 2019-06-14 07:05 | |
I used Linux. |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:58:26 | admin | set | github: 70368 |
| 2019-06-14 07:05:58 | mzamazal | set | messages: + msg345561 |
| 2019-06-13 15:47:23 | terry.reedy | set | messages:
+ msg345524 versions: + Python 3.9, - Python 2.7, Python 3.5, Python 3.6 |
| 2019-06-13 08:20:11 | jdemeyer | set | nosy:
+ jdemeyer messages: + msg345473 |
| 2019-06-11 20:32:08 | orivej | set | keywords:
+ patch stage: patch review pull_requests: + pull_request13849 |
| 2016-02-12 03:58:29 | ned.deily | set | nosy:
+ davin |
| 2016-01-29 16:01:15 | nirs | set | nosy:
+ nirs |
| 2016-01-25 08:22:10 | mzamazal | set | files:
+ bug3.py messages: + msg258896 |
| 2016-01-23 00:27:10 | terry.reedy | set | nosy:
+ terry.reedy messages: + msg258850 versions: + Python 3.5, Python 3.6, - Python 3.4 |
| 2016-01-22 15:24:46 | mzamazal | create | |