users@glassfish.java.net

Re: v2u1: server lag under "load"?

From: Scott Oaks <Scott.Oaks_at_Sun.COM>
Date: Thu, 08 May 2008 07:32:52 -0700

On May 8, 2008, at 7:28 AM, Kristian Rink wrote:

> Scott;
>
> Am Thu, 08 May 2008 07:16:29 -0700
> schrieb Scott Oaks <Scott.Oaks_at_Sun.COM>:
>
>> Take a look at the stack traces for the 8080 worker threads, you can
>> see that they are all calling out to an HTTP server. The fact that
>> they are all doing that is an indication that remote machine is
>> slow.
>
> well I think I am slowly getting to the core of the problem, looking
> at
> this:
>
> Thread "httpSSLWorkerThread-8080-0" thread-id 66
> [...]
> java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:373)
> at:
> com.caucho.hessian.client.HessianProxy.invoke(HessianProxy.java:145)
> at: $Proxy126.getProjectByID(Unknown Source)
> [...]
>
>
> Our application initially had a "backend" and a "frontend", connected
> via Spring-Remoting through Hessian. Being about to move them to the
> same machine, they right now live inside the same glassfish, obviously
> locally doing HTTP remoting calls. I am getting a sensation of causing
> a deadlock this way, making these applications wait for each other
> 'til
> the cows come home. Could this be the cause for my pain?

I should have thought of that -- yes, it is very easy to deadlock if
HTTP servers call each other (or if one HTTP server calls itself). I
have done that several times myself...

Changing the architecture first sounds like the better idea.

-Scott

>
>
> If so, I'll postpone anything else and do what I actually intended to
> do by moving to glassfish - dump the pointless "local HTTP remoting"
> in
> favor of making the backend an EJB application and using standard Java
> EE means of communication...
>
> Anyway, thanks a lot and best regards,
> Kristian
>
>
> --
> Kristian Rink * http://zimmer428.net * http://flickr.com/photos/z428/
> jab: kawazu_at_jabber.ccc.de * icq: 48874445 * fon: ++49 176 2447 2771
> "One dreaming alone, it will be only a dream; many dreaming together
> is the beginning of a new reality." (Hundertwasser)
>
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