[Zope-dev] many conflict errors

[Joachim Schmitz]

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