On Sat, Aug 20, 2011 at 7:52 AM, Sekhar <allur...@gmail.com> wrote: > We're about to launch a healthcare app, and we recently switched from M/S > to HRD (both with reserved instances). I'm really, really happy with HRD so > far, most importantly we don't see random hiccups in data access any more. > Performance has been really consistent.
Great to hear. It's also exactly what I'm hearing from others I've talked to who have switched from M/S to HRD. We are occasionally getting a new error "too much contention on these > datastore entities. please try again." however. Clearly it's not due to > traffic because it's like 5 of us testing the site at this point. I'm a bit > worried our patients/doctors will see this after launch next month. What's > this and is there a way to avoid it? > In both cases, you should design your application for at most 1 datastore write/second (=1qps) per entity group. You can write simultaneously to as many entity groups as you like. The problem you mention usually comes up in one of two scenarios: 1. You have a some shared / global data structure which is updated by multiple users at the same time, ultimately at a rate > 1qps. See http://code.google.com/appengine/articles/sharding_counters.html for a common technique for dealing with this. 2. You are testing with multiple users, but they are all logged in with the same account, or are otherwise artificially updating the same data. In this case you have a usage pattern which doesn't match what production traffic would look like. If you're wanting to build high throughput pipelines, check out http://www.google.com/events/io/2010/sessions/high-throughput-data-pipelines-appengine.html > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To view this discussion on the web visit > https://groups.google.com/d/msg/google-appengine/-/QygaPE8F_dwJ. > > To post to this group, send email to google-appengine@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. > -- Fred Sauer Developer Advocate Google Inc. 1600 Amphitheatre Parkway Mountain View, CA 94043 fre...@google.com -- 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-appengine@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.
