It sounds like you're looking for memcached CAS - http://groups.google.com/group/memcached/browse_thread/thread/b98fc70ddeb39650/f4febb23a0cd0db7?pli=1
Of course, this all begs the question of what you do if your data is expunged from memcached. Are you not also writing to the datastore (which has its own concurrency mgmt for cases like these)? James On Apr 23, 12:23 am, Phuong Nguyen <[email protected]> wrote: > Hi guys: > I'm creating an app that I need to deal with concurrent modification of > object. > Given I have an object that I need to store on memcache. > Now, given my user base would be big enough for two request to arrive > simultaneously at two different servers in the cloud. > So, in order to modify the object, the server #1 that receive request > fetch the object from memcache (Correct me if I'm wrong: this will > deserialized raw data on memcache in to Java Object on Server #1 JVM), > modify it and then put it back to memcache (which in turn serialize the > object). > At the same time, server #2 tried to modify the object on memcache. > > Under this scenario: Server #1 fetch object> Server #2 fetch object > > Server #1 store object > Server #2 store object > Then all changes make by Server #1 will be overrided by Server #2. > > If these 2 requests happen on the same Server (and in effect, the same > JVM), then I believe the use of synchronized access will help. But in > case they happen on different server, then I don't know how to handle > them yet. > > Would you guys advice me on that? > Thanks. > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine for Java" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group > athttp://groups.google.com/group/google-appengine-java?hl=en. -- You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en.
