[ZODB-Dev] Update on 'Random ValueError' bug

[Jim Fulton]

On Dec 21, 2006, at 4:11 AM, Christian Theune wrote:

> Hi,
>
> Chris Withers wrote:
>> Christian Theune wrote:
>>> I've tried to analyse the situation for this a bit. Some  
>>> annotations are
>>> in http://www.zope.org/Collectors/Zope/2151 and maybe this can  
>>> trigger
>>> more input.
>> Thanks for looking into this, any help is much appreciated!
>>> Note: I was a bad boy and used ZODB trunk for the analysis and  
>>> didn't
>>> remember that Chris was talking about 2.9.2 until I was done. I hope
>>> this area didn't change too much, otherwise I'd have to repeat that
>>> analysis. :/
>> zodb doesn't seem to have gotten that much attention since 2.9.x,  
>> unless I've missed something.

You have.  I spend a fair bit if time on it for the 2.10/3.3  
releases.  This was mainly to
chase a problem on the Mac but I ended up cleaning up some internal  
messiness
quite a bit.  Of course, there's also the blob work.

I also spent some time on this issue.  Chris and I went back on this  
in August:

   http://mail.zope.org/pipermail/zodb-dev/2006-August/010355.html

Unfortunately, when I made time to look at this, Chris was away on  
vacation.

>> I see you raised some possibilities in terms of what might be  
>> causing the problem. How should we go about eliminating these?
>
> That's the plan. This bug takes me quite some time to analyse, so I  
> don't promise any quick success here. If anybody (Jim?) can comment  
> on my findings to prevent me running in the wrong direction that  
> would be very helpful.

See the note from Chris lined above. It responds to and fortunately  
quotes a note from me
that I can't find. :/  I found a race condition that was fairly benign.

>
> Next step for me will be to verify the assertion that when calling  
> settid() it must be passed a strictly larger tid than the one before.
>
> There is no test currently assuring this or the opposite. Once I  
> find out, I'll update the tests.

At this point, I don't really remember many details.

Jim

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