Hi Tim, I agree.  It's not the persistence of any statics or memory
that concerns me though.  It's the fact that every time my VM gets
recycled, the next hit to my site takes a few seconds to resolve while
GAE spins up another JVM to service it.  It's the performance that I'm
more worried about, not to mention that every time GAE creates a new
VM for me, it takes significant CPU cycles to do so.


On Feb 12, 11:52 pm, Tim Hoffman <[email protected]> wrote:
> Hi
>
> You should never depend on any specific instance hanging around just
> the same
> as you cannot depend on anything in memcache hanging around.
>
> Rgds
>
> T
>
> On Feb 13, 12:29 pm, Charles <[email protected]> wrote:
>
> > Hi Brandon,
>
> > Thanks for the reply.  Just from a bit more research, this seems to be
> > related to loading requests (http://code.google.com/appengine/kb/
> > java.html#What_Is_A_Loading_Request) and their frequency.  From the
> > FAQ, it seems like with apps with minimal traffic, or test traffic,
> > VMs seem to be recycled during inactivity.  When subsequent requests
> > hit your app after your VM has been handed off, GAE has to spin up a
> > new JVM (a loading request) which re-initializes the entire context
> > (and also eats up significant CPU time).  Anyways, kinda sucks that
> > this is how it works, but I can understand why they'd want to do
> > that.  And, this only really affects apps in testing or production
> > apps with little traffic.  When we get real traffic, *hopefully* this
> > becomes a non-issue.
>
> > Also, it looks like they're playing around with the idea of being able
> > to pay to reserve a dedicated JVM (http://code.google.com/appengine/kb/
> > java.html#Can_I_Pay_To_Reserve_My_JVM).  This would be a good solution
> > as well.
>
> > Charles
>
> > On Feb 12, 12:31 pm, Brandon Thomson <[email protected]> wrote:
>
> > > Charles, the app instance can be unloaded at any time and a new one
> > > will initialize to handle the next incoming request. there can be up
> > > to 30 at once. it is by design, not an error.
>
> > > On Feb 12, 12:20 am, Charles <[email protected]> wrote:
>
> > > > Hi all,
>
> > > > I've created a very simple application as a test for a bigger
> > > > application I'm thinking of building on GAE.  Right now, it mostly
> > > > contains only two servlets and a single cron job.  One servlet is
> > > > loaded on init (and logs an init message), and the other one is called
> > > > every minute by the cron job (and also logs a message).  My issue is
> > > > that I'm watching the logs and I'm noticing that my applications
> > > > context is reloaded after an arbitrary amount of time.  To be more
> > > > precise, here is an example of what I'd see in the logs...
>
> > > > [INFO] Application initializing...
> > > > [INFO] Servlet called 1 times.
> > > > [INFO] Servlet called 2 times.
> > > > [INFO] Servlet called 3 times.
> > > > ...
> > > > [INFO] Servlet called 79 times.
> > > > [INFO] Servlet called 80 times.
> > > > [INFO] Application initializing...
> > > > [INFO] Servlet called 1 times.
> > > > [INFO] Servlet called 2 times.
>
> > > > So, as you can see, the application starts and the init servlet is
> > > > loaded (as expected) and I get the "Application initializing" info log
> > > > message.  After that, cron calls the other servlet every minute, and
> > > > it posts another log message.  However, after a seemingly random
> > > > amount of time, in this case 80 minutes, the application context
> > > > reloads which makes me assume that my entire application restarted.
> > > > It happens at different intervals each time, anywhere from half an
> > > > hour to a few hours.  And, I never get any error messages in my log.
> > > > Can someone help me understand this?
>
> > > > Thanks in advance
>
> > > > Charles

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