That is correct. You can not maintain state within the JVM and expect to get any long-term persistence or coherency.
You should use either memcache (which provides coherency) or the datastore (which provides both). On Wed, Jul 14, 2010 at 3:38 PM, Ingo Jaeckel <[email protected]>wrote: > hello everyone, > > i just had a look into the documentation > http://code.google.com/intl/de-DE/appengine/docs/java/runtime.html > > "App Engine uses multiple web servers to run your application, and > automatically adjusts the number of servers it is using to handle > requests reliably. A given request may be routed to any server, and it > may not be the same server that handled a previous request from the > same user." > > does this mean that there are n jvms on n servers running my > application. thus if i want to collect profiling information about my > server code i will always have to persist it in the db. it would not > be sufficient just to hold it within the app (thus within the jvm). > because i will have different application stats across the different > servers running my application in parallel and independently.. > > can anyone confirm this claim? > > kind regards, > ingo > > > 2010/7/13 ingo <[email protected]>: > > hello everyone, > > > > i want to collect some performance figures of my app on the server > > side. but i do not want to persist them in the database, i only want > > to collect them by changing the state of some class (i.e. changing > > class members like number of requests, number of method calls, etc). i > > want to read these values on the client side and display them in an > > administration panel (or a profiler-like ui). > > > > but currently i think the application state is at least lost after > > each new deployment. is this the only time the state is resetted? does > > a jvm holding my application state run all the time between each > > deployment? > > > > i have the same question regarding static members. i use singletons or > > static variables on server side to make sure they are constructed only > > once whenever their construction is expensive. so i want to make sure > > that the jvm holding the instances is running for a very long time to > > avoid reconstruction of them. however, it feels like the jvm is > > restarted relatively often (due to very low load on my app maybe) and > > thus the singletons are recreated during the jvm startup. > > > > kind regards, > > ingo > > > > -- > > You received this message because you are subscribed to the Google Groups > "Google App Engine for Java" group. > > To post to this group, send email to > [email protected]. > > To unsubscribe from this group, send email to > [email protected]<google-appengine-java%[email protected]> > . > > For more options, visit this group at > http://groups.google.com/group/google-appengine-java?hl=en. > > > > > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine for Java" group. > To post to this group, send email to > [email protected]. > To unsubscribe from this group, send email to > [email protected]<google-appengine-java%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine-java?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Google App Engine for Java" 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-java?hl=en.
