Moritz, Take a look at this article if you haven't done it yet.
http://code.google.com/intl/en/appengine/articles/update_schema.html It gives some recommendations that could be applicable to your task. Eventhough, it was written for Python, the same principals apply to Java. I'm also currently looking for a reliable way for datastore backup. Haven't found anything really besides mimicking java classes in Python and use Python-based backup utilities. So, if you find something more convenient, please post it here. Regards, Alex On Feb 2, 1:22 pm, Moritz <[email protected]> wrote: > Hello everyone, > > after a couple of versions of my application I found out that I need > to change the datamodel fundamentally in order to achieve better > performance. My approach was as follows: > > (Coding) > - Mark all old API as @Deprecated > - Create new classes etc. > - Update views etc. > - Develop a migration servlet which copies data from the old model to > the new model > (Migration) > - Deploy new app > - Call migration servlet URL > > All tests on my local development environment were successful. The new > datamodel is less complex than the old one, it contains only > "implicit" relations and stores large data in a separate entity. That > perfectly matches the application's scope, only minor refactorings > were necessary to implement the new datamodel. > > However, the migration failed. Of course, I had already so much data > in the system, that the request timed out. Now my datastore is half > old and half new. > > Bummer. > > Luckily, that application is not really in production, so it is not a > fatal loss. > > However, I'm wondering how such migration is usually done. > - How do I backup my datastore? > - How do I run migration "scripts" (in my case =servlet)? > > Thank you, > Moritz -- 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.
