CODEWITHSUNDEEP
pythonconcurrencyqueuecritical-section
user20426821
user20426821

Reputation:

Python, concurency, critical sections

here I have some question about possible critical sections.

  1. In my code I have a function dealing with queue. This function is one and only to put elements in the queue. But a number of threads operating concurently get elements from this queue. Since there is a chance (I am not sure if such a chance exists tbh) that multiple threads will attempt to get one element each from the queue at the same time, is it possible that they will get exactly the same element from the queue?

  2. One of the things my workers do is opening a file (different workers opens different files in exclusive dirs). I am using context manager "with open(>some file<, 'w') as file...". So is it possible, that at the same time multiple threads opening different files but using exectly the same variable 'file' will mess up things cause it looks like I have a critical section here, doesnt it?

Upvotes: 0

Views: 74

Answers (1)

Sintifo
Sintifo

Reputation: 58

Your first question is easy to answer with the documentation of the queue class. If you implemented a custom queue, the locking is on you but the python queue module states:

Internally, those three types of queues use locks to temporarily block competing threads; however, they are not designed to handle reentrancy within a thread.

I am uncertain if your second question follows from the first question. It would be helpful to clear up your question with an example.

Upvotes: 1

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