I've been using and watching appengine since, well, the beginning, and only by a random Google about an unrelated topic did I find out about this notion of a cap on 'simultaneous active requests'. I came across discussions where people were saying that there is a cap of 30 simultaneous active requests, citing the Quota page and so on.
But when I go to the Quota page - there's not a single mention of any such limit. Why not? Has something changed? Reading the quotas on that page it's easy to conclude - naively perhaps in hindsight - that 500 requests/second is 500 requests/second irrespective of the average execution time of those requests. There is no mention of any assumption on that page about the time taken to serve a request or anything else that goes into the calculation for 500 requests/second. After some further searching I finally found mention of this limit in the FAQs, but here it's still quite vague - and again, no specific mention of this 30 simultaneous request limit. It says: "However, App Engine reserves automatic scaling capacity for applications with low latency, where the application responds to requests in less than one second. Applications with very high latency (over one second per request for many requests) are limited by the system, and require a special exemption in order to have a large number of simultaneous dynamic requests. If your application has a strong need for a high throughput of long-running requests, you can request an exemption from the simultaneous dynamic request limit. The vast majority of applications do not require any exemption." Which doesn't imply a hard limit, but rather that as long as your (average?) request fulfilment time is below one second you shouldn't have to worry about this. To be very exacting, if I keep my average request time under 1 second I should *never* see an error relating to this cap? This is a bit different than the talk of 30 simultaneous requests max - at that level with the max of 500 requests a second, you'd be limited to an average request time of 60ms! So what is the story here? Why is this all being talked about in the shadows of message boards with no clear policy? Why isn't this limitation in the quota page? I thought I had GAE all figured out but then this ball gets thrown into the mix out of left field. -- 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-appeng...@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.
