PS: I read this interesting article http://groups.google.com/group/google-appengine/browse_thread/thread/6106e26990a4a457/c0481c7c6629f8e8?lnk=gst&q=sum#c0481c7c6629f8e8 It's about calculating statistics at write time. Really interesting.
On 9 apr, 19:55, michaelg <[email protected]> wrote: > Horizontal scaling of relational databases is non-trivial and Google > does not offer it. I can't say if they have something internally that > could work for some people, but it is such a tricky subject that it > would be hard to offer a general purpose, turnkey solution. As an > example, Google donated Hibernate Shards, a layer on top of the > popular Hibernate ORM that is designed to work with a horizontally > scaled database. They released this two years ago and it has been > sitting and rotting ever since. > > However, very few applications actually need a horizontally scaled > database. That is why folks like Microsoft and Sun are willing to > offer relational databases as part of their cloud platforms. There is > almost no chance that any customer will actually need this. And > chances are that a customer that did need this would probably be well > past the stage where they would want to use a cloud platform > anyways... > > As for Amazon, MySQL running on EC2 is not a horizontally scaled > database. It is a vertically scaled database (i.e. you can make the > box it runs on bigger, but it is still one DB on one box, plus maybe > some read slaves.) Again, this is perfect for the vast majority of > applications. Amazon's SimpleDB is very similar to Google's DataStore. > It is not relational, but it will scale horizontally. It has many of > the same restrictions and downsides that DataStore > has:http://highscalability.com/current-pros-and-cons-list-simpledb > > Finally, make no mistake that there is no substitute for a relational > database. RDBMS is very sophisticated technology. There are decades of > complex mathematics and computer science behind it. Things like joins, > views, ACID transactions, and integrity constraints are easy to take > for granted, but not so easy to reproduce/reinvent. Many applications > can greatly benefit from these standard features of most relational > databases. Weighing the simplicity and scalability of GAE DataStore > vs. the benefits of a relational database is one of the most critical > factors in picking a cloud platform. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
