I just added this comment, which explains why the GAE result is anemic. The GAE test was flawed to the point of irrelevance; hopefully the author will retest with a realistic scenario.
My comment: --- It is not quite correct to say that the problem with GAE is related to sharding. As you know, you can only perform transactions within a single entity group. The bottleneck is not that this restricts processing to a single machine; the bottleneck is that each entity group (and thus each transaction) has a single optimistic timestamp. By placing your entire data structure in a single entity group, you have guaranteed that *every single operation* contends for a single optimistic lock in the database. The analogue to an RDBMS is not condensing all requests to a single machine; the analogue is putting an update of the exact same piece of data in *every* transaction. This simply won't work. To properly implement the GAE test, you can't just "add sharding"; you must eliminate the transaction requirement and allow every piece of data to live in its own entity group. Transactions in GAE are useful in a few isolated cases but they are NOT equivalent to RDBMS transactions and cannot be treated as such. Transactions as you are accustomed to are not a supported feature of the GAE datastore. I'm very interested in how GAE stacks up. You shouldn't need to rewrite your tests to support sharding in any explicit way, just remove the parent references and get rid of any transaction-related code. This doesn't offer the same consistency requirements as the other systems, but GAE doesn't support those kinds of consistency requirements. --- On Fri, May 28, 2010 at 2:39 AM, Peter Knego <[email protected]> wrote: > Has anyone read this? > > http://highscalability.com/blog/2010/5/26/end-to-end-performance-study-of-cloud-services.html > > Any thoughts on why App Engine seems to be slow? > > -- > 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. > > -- 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.
