I think that is big problem since GAE that no handle problem with customer experience of start-ups/low traffic application it kills traffic expansion.
First instance loads to slow to server first customer - result is drop with 500 status customer goes away that should not occur since it block traffic expansion. One method I know to deal with it is to write pinger which generate traffic to keep-a-live instance but it against good architecture design GAE should allow the same. Another method is always on but it need to be paid - better is write pinger with use cron (it should be called in time less than 15min) on GAE or other server. Pinger allow also to trace availability - you could measure if all pings occurs. On 14 Sty, 23:15, "Brandon Wirtz" <drak...@digerat.com> wrote: > Do you have a warm up handler configured in your Yaml? > If you don't then the new instance has to warm up and handle a request. > Specifying a Warm up that simply initializes some variables and logs an > event "Warm up complete". > > Should fix your issue. > > I don't think you have "Platform issues" I think you have Google hasn't > documented all best practices issues. > > From: google-appengine@googlegroups.com > [mailto:google-appengine@googlegroups.com] On Behalf Of Karl Rosaen > Sent: Saturday, January 14, 2012 6:26 AM > To: google-appengine@googlegroups.com > Subject: Re: [google-appengine] Why are several production issues related to > DeadlineExceededErrors being ignored? > > Thanks Brandon. Many of the DeadlineExceededErrors were occurring during > warmup requests, according to the stacktraces, during python import > statements. I upped the number of idle instances in an attempt to mitigate > this sort of thrashing, and your advice makes sense for this case. Our > pending latency is set to 'Automatic' on both ends. > > I'm attaching some graphs from the period when this was the worst > > Instances: > > <https://lh4.googleusercontent.com/--AtYMbWJ4ek/TxGNT3nfp0I/AAAAAAAAUu... > m78Mc08/s1600/Screen%252520Shot%2525202012-01-14%252520at%2525209.08.59%252 5 > 20AM.png> > > Requests per second: > > <https://lh6.googleusercontent.com/-LoIlwGhvLrA/TxGOnvzGmSI/AAAAAAAAUu... > YssPK_4/s1600/Screen%252520Shot%2525202012-01-14%252520at%2525209.17.39%252 5 > 20AM.png> > > Milliseconds per request: > > <https://lh5.googleusercontent.com/-A76zVs8CCEo/TxGNZ9kcpfI/AAAAAAAAUu... > uPvgw50/s1600/Screen%252520Shot%2525202012-01-14%252520at%2525209.09.41%252 5 > 20AM.png> > > This suggests that some higher latency handlers were hit (some people were > editing content), taking up the existing front end instances, after which > GAE was trying to spin up some dynamic instances to serve other requests. > But during warmup, there were DeadelineExceededErrors during file imports, > suggesting that the dynamic instances aren't being given enough time to > warmup. > > Increasing the idle instances helps. So perhaps the revised question, at > least for our particular situation is: why, under load, do the dynamic > instances timeout during warmup? That seems to compound the problem as the > dynamic instances aren't able to serve the requests that are backed up, > leading to user visible 500 errors, and more attempts to dynamically load > instances. > > Does my theory have any holes? Is relying on dynamic instances to handle > spikes without 500 errors unrealistic? I know the docs state, "A smaller > number of idle Instances means your application costs less to run, but may > encounter more startup latency during load spikes." but thrashing on > DeadlineExceededErrors during warmup seems to indicate that dynamic > instances can't be relied upon for load spikes at all right now. > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To view this discussion on the web > visithttps://groups.google.com/d/msg/google-appengine/-/bYRgRhlKZjoJ. > 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 > athttp://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 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.
