[Zope] Zope 2.8 and conflict errors

[Michael Dunstan]

On 2005-08-04, at 02:32 GMT+12:00, Maciej Wisniowski wrote:
> All errors are with OOBTree and as I can see with  
> tempstorage.TemporaryStorage. They look like:
>
> <li>  Module ZPublisher.Publish, line 187, in  
> publish_module_standard</li>
> <li>  Module ZPublisher.Publish, line 161, in publish</li>
> <li>  Module ZPublisher.Publish, line 161, in publish</li>
> <li>  Module ZPublisher.Publish, line 161, in publish</li>
> <li>  Module ZPublisher.Publish, line 151, in publish</li>
> <li>  Module Zope2.App.startup, line 158, in  
> zpublisher_exception_hook</li>
> <li>  Module ZPublisher.Publish, line 119, in publish</li>
> <li>  Module Zope2.App.startup, line 215, in commit</li>
> <li>  Module transaction._manager, line 84, in commit</li>
> <li>  Module transaction._transaction, line 381, in commit</li>
> <li>  Module transaction._transaction, line 379, in commit</li>
> <li>  Module transaction._transaction, line 424, in  
> _commitResources</li>
> <li>  Module ZODB.Connection, line 462, in commit</li>
> <li>  Module ZODB.Connection, line 503, in _commit</li>
> <li>  Module ZODB.Connection, line 526, in _store_objects</li>
> <li>  Module tempstorage.TemporaryStorage, line 200, in store</li>
> </ul>ConflictError: database conflict error (oid 0x0944, class  
> BTrees._OOBTree.OOBTree, serial this txn started with  
> 0x035f134dc11a2977 2005-08-03 12:29:45.258327, serial currently  
> committed 0x035f1357051c7199 2005-08-03 12:39:01.197916)

On 2005-08-04, at 09:02 GMT+12:00, Maciej Wisniowski wrote:
>
> so I hope that maybe next Zope 2.8.x release will be using MVCC for  
> OOBTree (if this is the point?). Does anybody know something about  
> that?

That looks like a write conflict. MVCC helps to lower/eliminate the  
rate of read conflicts.

One option to reduce the rate of this write conflict is to tune the  
session machinery to suit. For example use session-resolution-seconds  
of say 300 seconds.

michael