Hi Bernd, did you consider to use the OSCasche implementation with optimistic locking?
http://db.apache.org/ojb/docu/guides/objectcache.html#ObjectCacheOSCacheImpl http://db.apache.org/ojb/docu/howtos/howto-work-with-clustering.html I used that sometimes and it is very quick as the entries are not locked, but you got an exception where you try to store a "dirty read", so catching it you can decide what to do. Hope this helps Alessandro Colantoni On Wed, Mar 18, 2009 at 4:25 PM, Bernd Längerich <[email protected]>wrote: > Hello, > > I use the PB-API. Is there any support for concurrent access to the same > data base entries from multiple servers/applications in OJB? In order to > provide a scalable system and high availability, I am faced with the demands > of load balancing and multiple servers running the same application and > service. At the moment, multiple servers could obtain the same object > instance from the database, caching them, perform changes and possibly > updating the data base without notification of their neighbors. Completely > turning off caching is no real option at the moment. > > At the moment, my approach would be to lock the rows in the database during > transaction processing, thus disabling concurrent access to these entries. > After transaction is done, the instance would be held in cache. If > subsequent transactions are scheduled to the same server, everything is > fine, but there is a possibility that another server is scheduled one > transaction, making the cached instance obsolete. The best solution would > be, that the object instance remains in cache, but are updated from the > database when requested. > > Best regards > > Bernd > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] > >
