Hi Chau: Thanks for your tips. I've also found one in there: http://appengine-cookbook.appspot.com/recipe/mutex-using-memcache-api/ Pretty good solution to try, though.
On Apr 23, 9:53 pm, Chau Huynh <[email protected]> wrote: > Maybe you can look into low level API to obtain a > "lock"http://code.google.com/appengine/docs/java/javadoc/com/google/appengi... > > There're also sample implementation using this posted in the > grouphttps://groups.google.com/group/google-appengine/browse_thread/thread... > > On Fri, Apr 23, 2010 at 11:23 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]<google-appengine-java%[email protected]> > > . > > For more options, visit this group at > >http://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 > 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.
