[Zope-dev] Re: [Plone-users] Re: [ZODB-Dev] [Warning] Zope/ZEO clients: subprocesses can lead to non-deterministic message loss

[Dieter Maurer]

Paul Winkler wrote at 2004-6-25 17:41 -0400:
>On Fri, Jun 25, 2004 at 07:23:19PM +0200, Dieter Maurer wrote:
>> ATTENTION: Crosspost -- Reply-To set to 'zope-dev at zope.org'
>> 
>> Today, I hit a nasty error.
>> 
>> The error affects applications under Unix (and maybe Windows) which
>> 
>>   *  use an "asyncore" mainloop thread (and maybe other asyncore applications)
>> 
>>      Zope and many ZEO clients belong to this class
>> 
>> and
>> 
>>   *  create subprocesses (via "fork" and "system", "popen" or friends if
>>      they use "fork" internally (they do under Unix but I think not
>>      under Windows)).
>
>Hm.  this applies to external methods and product code that makes
>these calls?


Discussion in "zope-dev at zope.org" suggests that this problem
cannot occur as described with a POSIX fork implementation.

I observed the problem in a different setup and concluded
from the Linux "fork" manual page only that Zope's
"asyncore.mainloop" thread will suffer from the same problem.
I did not observe the behaviour in this setup and it is well
possible that it cannot occur.


-- 
Dieter