[Zope-dev] many conflict errors

[Chris McDonough]

You might try placing the session data container in the main ZODB  
FileStorage (or ZEO storage if you use ZEO) to see if it demonstrates  
fewer conflicts there than using one contained in a  
TemporaryStorage.  If you use ZEO, you will need to ensure that the  
Products.faster package can be imported from within the storage  
server itself (the storage server performs conflict resolution as  
opposed to each client doing it).

On May 23, 2007, at 1:12 PM, Joachim Schmitz wrote:

> Hi,
>
> in our Studentregistration portal we experience many conflict  
> errors under heavy load many of them unresolved.
>
> the configuration
>
> ZEO-server running on one machine
> 4 Zope-Clients with CPS-3.4.2 with 4 threads each running on a  
> second box, we are using the faster session product
>
> all running Zope 2.9.3, python 2.4.3 on Ubuntu 4.0.3
>
>
> a typical case looks like this:
> about 5 or 6 messages in the log file with the oid 0x2b
>
> 2007-05-23T17:32:38 INFO ZPublisher.Conflict ConflictError at / 
> VirtualHostBase/http/uniben.waeup.org:80/uniben/VirtualHostRoot/ 
> campus/students/S882364/study_course/create_level: database  
> conflict error (oid 0x2b, class  
> Products.faster.sessiondata.SessionDataContainer, serial this txn  
> started with 0x036dd29c28404f33 2007-05-23 16:28:09.433877, serial  
> currently committed 0x036dd29ed2491566 2007-05-23 16:30:49.285660)  
> (780 conflicts (73 unresolved) since startup at Wed May 23 05:56:52  
> 2007)
>
> and finally
>
> ------
> 2007-05-23T17:32:38 ERROR Zope.SiteErrorLog http://uniben.waeup.org/ 
> campus/students/S882364/study_course/create_level
> Traceback (innermost last):
>   Module Zope2.App.startup, line 173, in zpublisher_exception_hook
>   Module ZPublisher.Publish, line 121, in publish
>   Module Zope2.App.startup, line 240, in commit
>   Module transaction._manager, line 96, in commit
>   Module Products.CPSCompat.PatchZODBTransaction, line 175, in commit
>   Module transaction._transaction, line 433, in _commitResources
>   Module ZODB.Connection, line 484, in commit
>   Module ZODB.Connection, line 526, in _commit
>   Module ZODB.Connection, line 554, in _store_objects
>   Module tempstorage.TemporaryStorage, line 200, in store
> ConflictError: database conflict error (oid 0x2b, class  
> Products.faster.sessiondata.SessionDataContainer, serial this txn  
> started with 0x036dd29c28404f33 2007-05-23 16:28:09.433877, serial  
> currently committed 0x036dd29ed2491566 2007-05-23 16:30:49.285660)
>
> Even though we have many write operations the write operations  
> can't actually conflict, since each student only works on his own  
> documents.
>
> Any hints howto to get further insight into this problem is welcome.
>
>
> -- 
> Gruß Joachim
>
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