@pphalen just remember, you're reading replies from other developers, which are often biased (e.g. to a specific programming language) or coming from a different background; others wear mermaid costume; etc.
For instance, > Nothing in the datastore can change faster than once per second; is true *only* in case of a single entity group. So, you're better off reading official docs. What I'm saying is, you'll find a lot of posts in this forum that are more like personal opinions of single developers (even when they scream "app engine is broken" sending you a bunch of charts that somehow are supposed to confirm that). So you should treat it as such, and not as an "absolute truth" unless you trust the guy or this is a google employee who really knows what she's talking about. On Sunday, August 19, 2012 3:58:24 AM UTC+2, Jeff Schnitzer wrote: > > On Sat, Aug 18, 2012 at 8:59 PM, pphalen <[email protected]<javascript:>> > wrote: > >> Apps with a lot of rapidly mutating aggregation are hard. > > > > Hi, I'm new to app engine, so this is news to me. Could you please > > characterize a bit more? E.g., what is "a lot"? > > Nothing in the datastore can change faster than once per second; > imagine trying to keep a count of products sold when you're selling > hundreds per second. Sharding helps but it becomes tricky to get the > value in a timely manner when you get to hundreds of shards. If you > need a transactionally accurate count (say, you are selling N units > and you must not sell N+1 units) this becomes even harder - you have > to go out of the datastore to another tool like memcache increment(). > > There are other data storage technologies that are optimized for rapid > updates to atomic data. Redis, Mongo, and of course traditional > RDBMSes solve this problem pretty easily for most typical scaling > needs. There isn't an equivalent tool in the GAE toolbox. This > doesn't mean you can't use GAE even if your app does some of this > aggregation... but if you do a lot of it, the platform works against > you rather than for you. > > Jeff > -- 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/-/nD2WS0E_Vo8J. 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.
