[ZODB-Dev] More exciting ZODB errors ;-)

[Chris Withers]

Tim Peters wrote:
> 
> I don't know, but if I were you I'd try running for a while on entirely
> different hardware.

This is on a cluster of machines, with the errors not coming from any 
one machine as far as I can see...

>>10:05 - Couldn't load state for 0x013872b7: Traceback (most recent call
> 
> last):
> 
>>   File "lib/python/ZODB/Connection.py", line 704, in setstate
>>     self._setstate(obj)
>>   File "lib/python/ZODB/Connection.py", line 757, in _setstate
>>     self._load_before_or_conflict(obj)
>>   File "lib/python/ZODB/Connection.py", line 765, in
> 
> _load_before_or_conflict
> 
>>     if not (self._mvcc and self._setstate_noncurrent(obj)):
>>   File "lib/python/ZODB/Connection.py", line 788, in _setstate_noncurrent
>>     assert end is not None
>>AssertionError
> 
> Haven't seen a report of this before. 
 >
> It's trying to load state for a ghost
> object, but the oid has been invalidated, so (because of MVCC) it's trying
> to load state that _was_ current at the time the transaction began.  The
> assertion is griping because the non-current state it loaded doesn't appear
> to have a sane validity range (that `end` is None is claiming that the old
> state is still valid, but that can't be true if the oid has in fact been
> invalidated).
> 
> Smells like an internal MVCC bug to me.

Damn, I don't think I collector-ised this one, will do tomorrow...

cheers,

Chris

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