Don, I have sent you my application id through email (by doing reply
to author).
A few of things I should mention:
1) we're using JPA
2) we are not creating EMF by doing:
Persistence.createEntityManagerFactory("transactions-optional");
instead it is created through spring's LocalEntityManagerFactoryBean
(which we subclass to ensure only one instance of entity manager
factory)
The EMF initialization is done during spring intialization so it is in
the servlet initialization path and not request processing path. It
is just that if GAE chooses to start a new application instance to
service a request, then the application startup (servlet
initialization) occurs during request processing.
Len
On Sep 14, 10:37 am, Don Schwarz <[email protected]> wrote:
> Len, what is your application ID?
>
>
>
> On Mon, Sep 14, 2009 at 12:33 PM, Larry Cable <[email protected]> wrote:
>
> > can you move the EMF creation out of the request path into the
> > initialization path (Servlet.init(ServletConfig) or a static
> > initializer
> > in the Servlet class at startup ...
>
> > BTW I also am using Spring IoC to create and inject the JDO EMF
> > and I dont think I am seeing the same performance issues?
>
> > Do you see similar startup costs on the local dev server as well as
> > production?
>
> > good luck
>
> > - Larry
>
> > On Sep 13, 5:27 pm, lent <[email protected]> wrote:
> > > I have been doing some profiling on application startup and it seems
> > > that there is a large amount of overhead:
> > > - it takes about 5 seconds between the time the request is received to
> > > where our spring initialization code is invoked
> > > - creating an entity manager factory is taking on average 8+ seconds
> > > Sometimes these numbers can be much bigger than this, for example we
> > > have seen creating entity manager factory as much as 14 seconds.
>
> > > Given that the application needs to its own initialization (which we
> > > are trying to minimize), we find that the application initialization
> > > becomes very long and when the server is busy and the above number are
> > > even higher, the application initialization fails to complete in 30
> > > seconds. Note that this is just the application initialization part
> > > and then the actual request has to be processed which will take some
> > > amount of time.
>
> > > Given that applications can be started on any given request, it makes
> > > things difficult with application startup time and request processing
> > > time with the 30 second limit.
>
> > > Len
>
> > > On Sep 8, 10:04 am, lent <[email protected]> wrote:
>
> > > > Hello,
>
> > > > We have an application which uses GWT (using GWT RPC) on the client
> > > > side. When the application is left idle for a while (~15 minutes) and
> > > > the application sends a request, we get this reported on the client
> > > > side:
>
> > > > "The server encountered an error and could not complete your request.
> > > > If the problem persists, please report your problem and mention this
> > > > error message and the query that caused it."
>
> > > > In the log, the following is logged:
>
> > > > "Request was aborted after waiting too long to attempt to service your
> > > > request. Most likely, this indicates that you have reached your
> > > > simultaneous active request limit. This is almost always due to
> > > > excessively high latency in your app. Please seehttp://
> > code.google.com/appengine/docs/quotas.htmlformore details."
>
> > > > I believe that our application has been swapped out and and when the
> > > > request comes in the application is being loaded again as we see some
> > > > log entries we make when the application (servlet) gets initialized.
> > > > It does take some time to get the application initialized but the
> > > > error is reported way before 30 seconds has elapsed. Is there any way
> > > > to avoid this problem?
>
> > > > Len- Hide quoted text -
>
> > > - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
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