Emanuele D'Arrigo wrote: > Hi everybody, > > Assuming a snippet such as: > > threadLocalData = threading.local() > threadLocalData.myDictionary = self.myDictionary > > is it correct to say that threadLocalData.myDictionary is NOT a thread- > local -copy- of self.myDictionary but it's actually pointing to the > same object? > > If that's the case, and assuming I want to iterate over the dictionary > without it changing under my nose while I'm in the loop, would it be > better to encase the whole loop in lock-protected section or would it > be better to make a copy of the dictionary first and then iterate over > that one? Given that in this particular thread I do not want to modify > the dictionary, conceptually a copy would work. But would making > thread-local copy be just as slow as making the whole loop thread > safe? > It depends on how long it takes to iterate over the dict compared with how long it takes to copy the dict. Other threads will/should be denied access during the iteration/copying and therefore block, reducing throughput.
I'd probably use the snapshot approach (take a copy). -- http://mail.python.org/mailman/listinfo/python-list
