If you use a transaction to retrieve the entity by key (the URL) and then create one if it doesn't exist, only one entity should be successfully created in the event of a collision. Therefore, even if you create two different versions with different unique ids, only one should survive.
On Tuesday, August 7, 2012 8:08:42 AM UTC-4, Neo wrote: > > Hi Jeff, > > > Actually my requirement is that , Whenever I save a new entity, the id > field should get autogenerated. If I have to do it on my own (as you > suggested DatastoreService.allocateIds()), how do we handle scenarios like > two threads on different machines trying to store the newly created entites > in the datastore (thereby trying to assign different ids). I am not well > versed with all the concepts. If you can please elaborate, that would be > really useful. And you are right in guessing that I need the shortest > possible value. Hashes, I suppose are not guaranteed to be unique for two > different arbitrary strings. > > Thanks, > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To view this discussion on the web visit https://groups.google.com/d/msg/google-appengine/-/-zhJp8r7laMJ. To post to this group, send email to google-appengine@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
