To add on to Nick's note: global, distributed transactions are very expensive to do for all your writes. Even in the case of Slim3, the overhead is a multiplier on a write - you'll want to be very careful where you use this. If you use it on an operation that's frequent, you'll be paying a huge cost, one that you can likely avoid.
On Tue, Apr 6, 2010 at 4:38 AM, Yasuo Higa <[email protected]> wrote: > Hi Dexter, > > > The global conservation law is a show stopper for many banking type > > application in Google Apps. > > Check http://code.google.com/p/googleappengine/issues/detail?id=313 > > for details. > > > > It seems that google is not going to bring 2 row concurrency anytime > > soon. However if a large number of people are interested it might get > > a higher priority. > > > In Java world, Slim3, which is a framework, supports global transactions. > > http://sites.google.com/site/slim3appengine/slim3-datastore/transactions/global-transaction > > If python SDK supports explicit transactions, global transactions can > be implemented as Slim3. > > Explicit transactions means: > DatastoreService ds = DatastoreServiceFactory.getDatastoreService(); > Entity entity = new Entity("Aaa"); > Entity entity2 = new Entity("Bbb"); > Tranaction tx = ds.beginTransaction(); > ds.put(tx, entity); > //this operation will execute without transaction > ds.put(null, entity2); > tx.commit(); > > Thanks, > > Yasuo Higa > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<google-appengine%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en. > > -- Ikai Lan Developer Programs Engineer, Google App Engine http://googleappengine.blogspot.com | http://twitter.com/app_engine -- You received this message because you are subscribed to the Google Groups "Google App Engine" 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?hl=en.
