The scheduler is most likely made with larger applications in mind (hundreds of instances). I saw plenty of isses when I tried to optimise for few instances. I had very similar issues as you had, when I was on a 2/2 setting for instance. Basically I wanted to have 2 instances all the time, and I tried 2/2, 2/3, 3/3, 1/3, and 1/2.
But what works best (by far!) for me at the moment is the setting "automatic/3". I decided to use the F4 instance as well. It now turns out I always have 2 or 3 instances running, but only get charged for one :) And very few spin-up and spin-down happening. And consistently fast responses too. Every app is different, so do experiment a bit. On Thursday, April 5, 2012 4:30:00 AM UTC+2, Tapir wrote: > > In my previous post, > > > http://groups.google.com/group/google-appengine/browse_thread/thread/c5ab4ec85c5b5525/b8f97af3ddcdcaa1?lnk=gst&q=charming#b8f97af3ddcdcaa1 > > > I said "after I rewrote the custom warm-up servlet, I found it works > like a charming". > Yes, the warm-up cases really becomes fewer, but now I find it still > exits. > > After some research, I found the behavior of the instance scheduler is > uncertain. > > Here is a case: one resident instance is idle, a new request coming, > the idle resident instance will handle it. At the same time, another > new request coming, the scheduler wait pending latency time, the idle > instance is still not free, so a new instance is started, which needs > 20-30 seconds to warmup. After ***N seconds***, the scheduler found > the new instance is still not warmed-up and found the resident > instance is free now, so the scheduler let the resident instance also > hand the second new request. > > The implementation is not bad, but the strange thing is ***N > seconds*** varies from 1 second to 30 seconds. > That is why some warm-up requests will be still encountered. > > btw, I found affer I rewrote the custom warm-up servlet, 99% percent > cases of the effort to create a new instance are useless. The new > created instance will be shutdown without handling any user requests. > > -- 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/-/PdQTyE299w4J. 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.
