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Created on 2020-06-08 06:59 by r n2, last changed 2022-04-11 14:59 by admin. This issue is now closed.
| Messages (4) | |||
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| msg371147 - (view) | Author: Raymond Hettinger (rhettinger) *  |
Date: 2020-06-10 00:50 | |
This code looks correct to me. For condition variables, the requirement is that the underlying lock be held when notify() is called. The not_full and not_empty condition variables share the same underlying lock, so it is sufficient that not_empty.notify() is called inside the body of "with self.not_full". |
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| msg371150 - (view) | Author: Raymond Hettinger (rhettinger) * |
Date: 2020-06-10 01:23 | |
Also note that threading.Condition.notify() would raise a RuntimeError if the underlying lock had not been acquired. Have you observed any behavior to the contrary? |
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| msg371162 - (view) | Author: r n (r n2) | Date: 2020-06-10 06:03 | |
Thanks for the response. However, if you see, every condition object has their own queue of waiters in self._waiters, that get notified during notify(), which are different for not_empty and not_full. I see a hang very very rarely, like 1/25 times, in my program, which keeps, reading from and writing to a queue from multiple threads. |
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| msg371164 - (view) | Author: r n (r n2) | Date: 2020-06-10 06:08 | |
Sorry, please ignore my previous comment, I can see that the issue is not in the queue, but probably be somewhere in my setup. I'll close this bug therefore. Thanks again for the clarification. |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:59:32 | admin | set | github: 85084 |
| 2020-06-10 06:08:40 | r n2 | set | status: open -> closed resolution: not a bug messages: + msg371164 stage: resolved |
| 2020-06-10 06:03:58 | r n2 | set | nosy:
+ r n2 messages: + msg371162 |
| 2020-06-10 01:23:53 | rhettinger | set | messages: + msg371150 |
| 2020-06-10 00:50:54 | rhettinger | set | nosy:
+ tim.peters messages: + msg371147 |
| 2020-06-09 14:58:22 | r n2 | set | versions: + Python 3.9, Python 3.10 |
| 2020-06-08 21:05:03 | r n2 | set | nosy:
+ rhettinger, - r n2 title: cpython/queue.py: put() does not acquire not_empty before notifying on it -> cpython/lib/queue.py: put() does not acquire not_empty before notifying on it |
| 2020-06-08 07:03:33 | r n2 | set | title: cpython/queue.py: put() does not acquire not_empty lock before notifying on it -> cpython/queue.py: put() does not acquire not_empty before notifying on it |
| 2020-06-08 07:03:03 | r n2 | set | versions: + Python 3.6, Python 3.7 |
| 2020-06-08 06:59:47 | r n2 | create | |