I'm going to be the dissenting here. You should consider #1 if you know that you're always going to have on the order of 100 items. You can easily cache this value in memcache.
When you get into thousands of items you start to see the point at which it's not practical to do on-the-fly sums, even just to store the result in memcache. But less than thousands, might as well just calculate the sum. Pre-aggregating the sum is not necessarily trivial. If the sum changes more than once per second you need to shard the sum. Once you get to 100 shards, you've created a system that doesn't perform any better and is a hell of a lot more complicated. One thing to watch out for is eventuality - if your sum needs to be instantaneously correct, a simple query (on the HRD) may provide lagged data. On the other hand, if you are fetching your articles by key (and have STRONG consistency configured), you're ok. Jeff On Thu, Oct 27, 2011 at 12:49 PM, Jose Montes de Oca < [email protected]> wrote: > Hi Mos, > > You should design your data models as a non relational database, where > having redundancy its just fine. > > Plain and simple: > > 1/ will not scale, Not suitable for App Engine non relational database > (Datastore) > > 2/ Right Approach, just need to be careful on what voscausa said. > > Hope this helps! > > Jose Montes de Oca > > -- > 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/-/sUbapsIqigAJ. > > 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.
