By the way, I should mention that there is no Java SDK. This is *almost* completely a server side change.
The Python SDK ships with migration tools for migrating an existing application to an HR instance. As of right now, there are no Java tools - please use the Python SDK if you need this functionality. -- Ikai Lan Developer Programs Engineer, Google App Engine Blogger: http://googleappengine.blogspot.com Reddit: http://www.reddit.com/r/appengine Twitter: http://twitter.com/app_engine On Wed, Jan 5, 2011 at 3:15 PM, Ikai Lan (Google) <ikai.l+gro...@google.com<ikai.l%2bgro...@google.com> > wrote: > Hey everyone, > > If you don't already subscribe to our blog in your RSS reader, I advise > that you do so: > > > http://googleappengine.blogspot.com/2011/01/announcing-high-replication-datastore.html > > I've embedded the post below. This is a feature that I'm very excited > about. Feel free to post to this thread if you have any questions. > > Announcing the High Replication Datastore for App > Engine<http://googleappengine.blogspot.com/2011/01/announcing-high-replication-datastore.html> > > When App Engine launched over two years ago, we offered a Datastore that > was designed for quick, strongly consistent reads. It was based on a > Master/Slave replication topology, designed for fast writes while still > allowing applications to see data immediately after it was written. For the > past six months, as you are probably aware, we’ve been struggling with some > reliability > issues<http://googleappengine.blogspot.com/2010/06/datastore-performance-growing-pains.html> > with > the App Engine Datastore. Over the course of the past few months, we’ve made > major strides in fixing these issues. However, our experience with these > issues has made us rethink some of our design assumptions. As we promised > you in some of our outage > reports<https://groups.google.com/group/google-appengine-downtime-notify/msg/e9414ee6493da6fb?pli=1> > earlier > this year, we wanted to give you a more fundamental solution to the problem. > > Today I’m proud to announce the availability of a new Datastore > configuration option, the High Replication Datastore. The High Replication > Datastore provides the highest level of availability for your reads and > writes, at the cost of increased latency for writes and changes in > consistency guarantees in the API. The High Replication Datastore increases > the number of data centers that maintain replicas of your data by using the > Paxos > algorithm <http://labs.google.com/papers/paxos_made_live.html> to > synchronize that data across datacenters in real time. One of the most > significant benefits is that all functionality of your application will > remain fully available during planned maintenance periods, as well as during > most unplanned infrastructure issues. A more detailed comparison between > these two options is available in our > documentation<http://code.google.com/appengine/docs/python/datastore/hr/> > . > > From now on, when creating a new application, you will be able to select > the Datastore configuration for your application. While the current > Datastore configuration default remains Master/Slave, this may change in the > future. > <http://2.bp.blogspot.com/_dLfQMJsmsaI/TSTL4Cwfg3I/AAAAAAAAAI8/LR_gHxATJto/s1600/hr.png> > Datastore configuration options when creating an app. > > The datastore configuration option can not be changed once an application > is created, and all existing applications today are using the Master/Slave > configuration. To help existing apps migrate their data to an app using the > High Replication Datastore, we are providing some migration tools to assist > you. First, we have introduced an option in the Admin Console that allows an > application toserve in read-only > mode<http://code.google.com/appengine/docs/adminconsole/applicationsettings.html#Disable_Datastore_Writes> > so > that the data may be reliably copied between apps. Secondly, we are > providing a migration tool with the Python SDK that allows you to copy from > one app to another. Directions on how to use this tool for Python and Java > apps is documented > here<http://code.google.com/appengine/docs/adminconsole/datastoreadmin.html#Copying_Entities_to_Another_Application> > . > > Now, a word on pricing: Because the amount of data replication > significantly increases with the High Replication datastore, the price of > this datastore configuration is different. But because we believe that this > new configuration offers a significantly improved experience for some > applications, we wanted to make it available to you as soon as possible, > even though we haven’t finalized the pricing details. Thus, we are releasing > the High Replication Datastore with introductory pricing of 3x that of the > Master/Slave Datastore until the end of July 2011. After July, we expect > that pricing of this feature will change. We’ll let you know more about the > pricing details as soon as they are available, and remember, you are always > protected when pricing changes occur by our Terms of > Service<http://code.google.com/appengine/terms.html>. > Due to the higher cost, we thus recommend the High Replication Datastore > primarily for those developers building critical applications on App Engine > who want the highest possible level of availability for their application. > > Thank you, everyone, for all the work you’ve put into building applications > on App Engine for the past two years. We’re excited to have High Replication > Datastore as the first of many exciting launches in the new year, and hope > you’re excited about the other things we’ve got in store for App Engine in > 2011. > Posted by Kevin Gibbs, The App Engine Team > > > > -- > Ikai Lan > Developer Programs Engineer, Google App Engine > Blogger: http://googleappengine.blogspot.com > Reddit: http://www.reddit.com/r/appengine > Twitter: 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 google-appeng...@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.
