[Zope] Conflict error

Maciej Wisniowski maciej.wisniowski at coig.katowice.pl
Mon Nov 20 15:57:58 EST 2006


> Often I see messages like the following in the event log:
> 
> 2006-11-20T11:57:33 INFO ZPublisher.Conflict ConflictError at
> /<***some location***> : database conflict error (oid 0x03a7, class
> BTrees._OOBTree.OOBTree, serial this txn started with
> 0x0369ab934257a788 2006-11-20 16:51:15.549000, serial currently
> committed 0x0369ab9975fb5b99 2006-11-20 16:57:27.652000) (122
> conflicts (2 unresolved) since startup at Fri Nov 17 16:01:43 2006)
This specific message is just INFO, so it isn't visible to user, but
there is a statement abotut "(2 unresolved)" conflicts, and this is
worse because somebody has seen message about ConflicError.

Errors with OOBTree may be connected with session machinery. We had such
problems under high load and ZEO. Changing session_resolution_seconds
value in zope.conf to 300 solved the problem. You may try this but, if I
remember correctly, it will cause that your sessions timeout may be 300
secs longer and/or shorter. You may try other values.
It may be interesting what is <***some location***> too.


> I am also seeing the server go into some sort hard crash (actually it
> doesn't crash just seems to peg the cpu doing something) ...that seems
> related. (but I am not totally sure). Sometimes it "magically"
> recovers but more often than not I have to restart the service to get
> some sense of normality.
So what is a 'crash' for you? Any errors in event
log or Zope just doesn't answer for a long time? If the latter thing
then there is a DeadlockDebugger that shows what is Zope doing, even
when it is not responsible, but I'm afraid that it won't work under
Windows, but I've never tried.

> What does this message mean -- should I be worried about it? 
As far as you see only INFO it is nothing bad, but ERROR that
means conflict error was unresolved is visible to the user, although
hitting 'Refresh' usually is enough.

There you may find some informations (but this is based on zope 2.7):
http://www.plope.com/Members/dunny/conflicts/view

-- 
Maciej Wisniowski



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