[Zope] Product removal stress: a plea for help

[seb bacon]

If anyone can shed some light on this it would be a great help to the
newbies out here.  Perhaps I could even do a HOWTO, and lighten the load on the list considerably ;)

I don't have a solution to Alexander's problem quoted below, but it's one I keep hitting and
one that is frequently asked on this list.  In fact it's one I recently
asked for more info on, to no avail.  So I thought I'd add my
voice to the clamour.

Deleting products seems to be a very risky business in Zope.  Things
apparently get left behind in the ZOBD which shouldn't be there.  If I
delete a product that was used at some point elsewhere, I don't just get
broken objects, I get pickled data streaming out of my Zope most of the
time.  Today I had an interesting one: I thought I had cleaned
up thoroughly after an unwanted product, and I was getting no error
messages and no pickled junk on stderr.  The only thing I couldn't do is
add ZClasses, for which I got the error message quoted by Alexander
below (could not load object oid=[random character]).

Please, can any Master Zopician give an explanation:
1) what causes this kind of error?
2) how do you debug it?
3) how do you fix your Data.fs?

Thanks!  Seb.

* Alexander Chelnokov <alex@orto.unets.ru> [001108 18:21]:
> Hello All,
> 
> After a linux machine crash or cold restart something strange is going
> on with Zope (2.2.2) - all objects built on ZClass-based products like
> Yihaw or QSurvey are broken. Products are in Product folder, and i
> even can add an object and it works, but when i try to access it in a
> new browser window it reports
> ==========
> This object is broken because the unknown product that created it is
> no longer installed or is installed incorrectly. Please contact your
> product vendor for assistance.  
> Note that the data associated with this product has not been lost, and
> will be accessible again if the product is reinstalled.
> ==========
> 
> Well, i removed QSurvey and tried to re-install its current version -
> something goes wrong again:
> 
> ==========
> Zope Error
> Zope has encountered an error while publishing this resource. 
> 
> Error Type: Could not load oid ={, pickled data in traceback info may
> contain clues
> Error Value: None
> ==========
> 
> Is there any way to fix ZODB less radical than complete reinstall?
> 
> -- 
> Best regards,
>     Alexander N. Chelnokov
> Ural Scientific Institute of Traumatology and Orthopaedics
> 7, Bankovsky str. Ekaterinburg 620014 Russia
> ICQ: 25640913  
> 
> 
> 
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