billiard a multiprocessing py2 fork/backport has https://billiard.readthedocs.io/en/latest/library/multiprocessing.html#multi... with maxtasksperchild On Sat, 26 Jun 2021, 16:57 Ram Rachum, wrote:

Hi guys,

I want to have a version of `concurrent.futures.ProcessPoolExecutor` in which every worker process shuts down after each task. I want this because I believe I have a memory leak in my program that I wasn't able to fix. (Possibly it's in C extensions that I use.)

Since I'm going to use a process pool anyway, I'm hoping to sidestep this memory leak by launching every task on a worker process that shuts down after it's done.

A few years back when I was working at Dell, they did something similar. They had a Python server that had a memory leak, and they worked around it by having a process that can be easily restarted, and then they restarted it often.

The plan is that each new work item will run on a fresh process that has no memory leaks from previous work items.

I looked at the `futures/process.py` file to see whether I could subclass `ProcessPoolExecutor` and add this functionality, and boy oh boy this is not easy.

Do you think it's worthwhile to add this feature to `ProcessPoolExecutor`?

Thanks, Ram. _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-leave@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/UNDY7Y... Code of Conduct: http://python.org/psf/codeofconduct/

On Sat, Jun 26, 2021 at 11:59 AM Ram Rachum wrote:

Do you think it's worthwhile to add this feature to `ProcessPoolExecutor`?

*restart_workers* certainly seems worth further investigation and consideration. However, you may also be able to find a workaround using the *initialzer* argument for ProcessPoolExecutor. A detailed description is found in the docs for ThreadPoolExecutor: *initializer* is an optional callable that is called at the start of each worker thread; *initargs* is a tuple of arguments passed to the initializer. Not certain and could be decently involved, but figured it may be a lead worth sharing. :) With loving-kindness, On Sat, Jun 26, 2021 at 11:59 AM Ram Rachum wrote:

Hi guys,

I want to have a version of `concurrent.futures.ProcessPoolExecutor` in which every worker process shuts down after each task. I want this because I believe I have a memory leak in my program that I wasn't able to fix. (Possibly it's in C extensions that I use.)

Since I'm going to use a process pool anyway, I'm hoping to sidestep this memory leak by launching every task on a worker process that shuts down after it's done.

A few years back when I was working at Dell, they did something similar. They had a Python server that had a memory leak, and they worked around it by having a process that can be easily restarted, and then they restarted it often.

The plan is that each new work item will run on a fresh process that has no memory leaks from previous work items.

I looked at the `futures/process.py` file to see whether I could subclass `ProcessPoolExecutor` and add this functionality, and boy oh boy this is not easy.

Do you think it's worthwhile to add this feature to `ProcessPoolExecutor`?

Thanks, Ram. _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-leave@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/UNDY7Y... Code of Conduct: http://python.org/psf/codeofconduct/

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