[Python-ideas] Optimistic Concurrency

Terry Reedy tjreedy at udel.edu
Sun Oct 19 00:23:35 CEST 2008

Leif Walsh wrote:

> I see that now, but wasn't the original post about removing the GIL?
> That seems to imply that the users would be different threads in a
> program, with high speed and possibly high collision rate.

When I said 'impractical', I was thinking about this sort of situation.
'Optimistic Concurrency' is optimistic about not colliding ;-).
Else the recovery overhead makes it worse than locking.

> If we are talking about users communicating over http, this seems like
> something you'd write a program in python to do (like wikipedia says
> Rails does), and it doesn't seem to merit discussion in the
> development of python itself.

Servers have several threads, each communicating with and representing 
to the rest of the system one user.  When those several threads all edit 
shared data, should they have to acquire GIL, local locks, or none at 
all?  The point of the article is that 'no lock' is desirable when many 
locks would be left to expire unused and often also possible.


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