I think the gap here is that a RDBMS (PostgreSQL) and the App Engine Datastore are totally different. In fact, I think the latter influences your design much more than the former.
The sorts of joins you used to be able to do in your DB to efficiently retrieve data don't work in the GAE datastore. You need to build your data model around the queries you want to run efficiently. To say again, your data needs to be modeled to support your most important queries. I go through some of the reasoning in the modeling section of my blog (I've been away from GAE for a while so some of this could have changed): http://objectuser.wordpress.com/google-app-engine/ However, if you've not done so, I highly recommend reading the Google documentation: http://code.google.com/appengine/docs/java/datastore/ On Mar 5, 6:54 am, vennervald <jacob.vennerv...@gmail.com> wrote: > Hi Guys > > We have a small application running on JBoss, Seam, Hibernate and > PostgreSQL that we are thinking about moving to GAE/J. > To test the datastore we uploaded our data 1-1 so all our tables from > Postgres were represented as entity types in the datastore with the > entities relating to eachother through their keys. > As a proof of concept of the performance of the datastore, we did an > implemented one of our heaviest reports by joining 6 entities > together. And the performance proved to be really bad. Infact we > received the deadline exception before we got to join all the > entities. From the platform we are running on now, this could be done > in less than a second. > This doesn't tell me that Google datastore is worthless. It tells me, > that I'm doing something wrong, and that I need to think differently > about the data structures to make it perform on GAE. > I've been looking around and I can't seem to find really good sources > on datastore/JDO best practises. > Does anybody have any good resources on this toppic? > I would really apriciate your help. > > /Jacob :) -- 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 google-appengine-j...@googlegroups.com. To unsubscribe from this group, send email to google-appengine-java+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en.
