New submission from GranPrego <josephdel...@googlemail.com>:
On windows 7 / 10 I'm using subprocess to launch a dos cmdline executable and
returning the results, which is all working fine.
However, each time I make a call, the Python handle count is gradually
increasing, jumping up , back a few, then jumping up and so on.
All the handles are released when the script exits, but quite often python just
hangs after a few hours. If I use process explorer to investigate I can see
that python has an increasing number of Thread handles, even though I can see
the process being called and cleanly exiting.
Unfortunately I'm stuck with the dos executable and it's always a one shot of
sending it a single command each time and the script calls it a lot. The
executable is just taking a string cmdline and returning a couple of lines of
text and then exiting. It only runs for a couple of seconds at most.
I've tried two variants of calling the process, I was hoping that the with
variant would clean up, but there is no difference.
Each handle object that gets left behind has a single reference and a non paged
quota of 1192, 0 paged.
The script is long running and I've seen the handle count reach 46K.
result = ""
with Popen ([fcptool, parameters], stdout=PIPE, universal_newlines=True,
bufsize=1) as process:
for line in process.stdout:
result = result + line
return result
or
p = subprocess.run([fcptool, parameters], stdout=subprocess.PIPE,
stderr=subprocess.STDOUT, universal_newlines=True, shell=True).stdout
return p
I can reproduce this on 3 different machines, 2 windows 7 and one windows 10,
all Python 3.6. I can't see a way around this at the moment and as far as I
can tell, I'm using the call to subprocess correctly.
----------
components: Interpreter Core, Windows
messages: 317296
nosy: GranPrego, paul.moore, steve.dower, tim.golden, zach.ware
priority: normal
severity: normal
status: open
title: Subprocess Thread handles grow with each call and aren't released until
script ends
type: resource usage
versions: Python 3.6
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Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue33603>
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