[Zope] resolving conflict errors

Chris McDonough chrism at plope.com
Thu Dec 8 23:54:01 EST 2005


On Dec 8, 2005, at 9:29 PM, Dennis Allison wrote:

> On Fri, 14 Oct 2005, Chris McDonough wrote:
>
> The problem I am trying to resolve appears to be load related.  The
> observed symptom is that (some) session variables spontaneously  
> disappear.
> There appears to be some connection to conflicts, but the exact  
> mechanism
> and the relationship is not yet clear.

It's hard to know what's happening here, obviously.

>
> So, I've been looking through the code trying to find places where  
> some
> infrequent event could cause the problem.
>
> Chris pointed out that session variables can cause conflict errors  
> (both
> read-read and read-write)  when the session API is used.  I've been  
> trying
> to explore that interface and have not yet found all the pieces.  Some
> hints to the reader would help.

If you mean the session API, that's defined in modules within  
Products/Sessions and Products/Transience.

> I see where HTTPRequest manages the Zope user interface to the
> session variables which includes a mechanism for lazy access--the
> dictionary _lazies provides a list of callables.  When a variable is
> accessed, it is promoted to Request by executing the callable and  
> storing
> the value.  The _lazies entry corresponding to the session variable is
> deleted.

Sorry, I'm not sure what this means.  Are you describing what happens  
in the REQUEST.set_lazy code or are you describing a symptom of a  
problem?

>   What I have not been able to find is where this is maintained
> in a persistent fashion.  Can someone provide a pointer?

I'm not sure what this means either, sorry!  Where what is maintained  
in a persistent fashion?

Sorry to not be more helpful on this go-around. ;-)

- C



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