[Zope-dev] many conflict errors

Perry js at aixtraware.de
Fri May 25 09:42:02 EDT 2007

Maciej Wisniowski schrieb:
> Perry napisał(a):
>> Answering to myself:
>> we could get rid of the sessionrelated conflict errors, by removing all
>> session = context.REQUEST.SESSION
>> from our scripts. But we still have these conflict errors:
>> how can I find out, what causes these conflicts.
>> 2007-05-25T10:17:50 INFO ZPublisher.Conflict ConflictError at
>> /VirtualHostBase/http/uniben.waeup.org:80/uniben/VirtualHostRoot/campus/students/U431409/study_course/create_level:
>> database conflict error (oid 0x7905e6, class BTrees._IOBTree.IOBucket,
>> serial this txn started with 0x036ddc2a44454dee 2007-05-25
>> 09:14:16.000950, serial currently committed 0x036ddc2c21950377
>> 2007-05-25 09:16:07.870801) (80 conflicts (10 unresolved) since startup
>> at Fri May 25 05:19:08 2007)
> Try to change session resolution seconds (Timeout resolution (in seconds))
> parameter to a larger value. Possibly you're ecountering same problem as I
> had some time ago. With long requests and small session resolution
> seconds I had a lot of conflict errors.

I set it now to 9600/4800 (Timeout/Resolution) but it seams that it has 
no effect.

> I think it is because of way sessions work in zope. Every x
> seconds (where x is 'session resolution seconds'), when there is access
> to SESSION, session objects are moved in OOBTrees. It is used to handle
> session expiration.
> Not used session objects are moved to the end of the
> 'list' and finally removed after Session Timeout is reached. I don't
> know how this exactly goes but it is something like that.
> When this 'movement' happens during request (session object is moved
> when request that is bound to it is still being served) this causes
> conflicts. You may look at group archives for my posts month or two
> months ago...
I read this already I am also using the faster-session product and 
patched it to use the AppendOnlyDict.


Gruß Joachim

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