[issue3831] Multiprocessing: Expose underlying pipe in queues

[Andres Freund]

Andres Freund <andres at anarazel.de> added the comment:

As soon as some bytes are signalled as being available one can simply do a normal get(). I don't really see the problem here?
Sure, the get() might not be completely non-blocking (especially if the transferred event is more than the size of a pipe-buffer) but I have a hard time seing that as a problem as that should be both rare and only last a short time.

My personal use-case is being able to efficiently wait for evens from different queues - using the standard api one currently can only do that by busy looping...

The biggest thing I see where you have to be careful here is some stomping herd phenomenon you will get into if you have multiple readers doing a poll().
Namely *all* off those processes will awake and run into .get() which isnt exactly nice, but thats hardly solvable on python level.

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nosy: +andresfreund

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue3831>
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