[Python-Dev] Pythonic concurrency (original) (raw)

Josiah Carlson jcarlson at uci.edu
Tue Oct 11 20:26:42 CEST 2005

"Robert Brewer" <fumanchu at amor.org> wrote:

"Somewhat alleviated" and somewhat worsened. I've had half a dozen conversations in the last year about sharing data between threads; in every case, I've had to work quite hard to convince the other person that threading.local is not magic pixie thread dust. Each time, they had come to the conclusion that if they had a global variable, they could just stick a reference to it into a threading.local object and instantly have safe, concurrent access to it.

boggles Perhaps there should be an entry in the documentation about this. Here is a proposed modification.

Despite desires and assumptions to the contrary, threading.local is not magic. Placing references to global shared objects into threading.local will not make them magically threadsafe. Only by using threadsafe shared objects (by design with Queue.Queue, or by desire with lock.acquire()/release() placed around object accesses) will you have the potential for doing safe things.

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