On May 8, 2008, at 7:01 AM, Kristian Rink wrote:
> Scott, *;
>
> first off, thanks a bunch for your hints on that. Much appreciated
> as I
> had almost given up on getting this resolved somehow. :(
>
>
> Am Thu, 08 May 2008 06:51:25 -0700
> schrieb Scott Oaks <Scott.Oaks_at_Sun.COM>:
>
>> The important threads to look at are the httpSSLWorkerThread-8080 --
>> those are the threads that handle the HTTP requests. In your case,
>> all of those threads are blocked waiting for a response from some
>> remote HTTP server. That server is apparently slow, tying up all the
>> HTTP threads in your appserver.
>
> Is this a matter of a server being slow or also likely of having large
> requests being processed? The glassfish, like most of our environment,
> is fronted by a reverse-proxying apache2/mod_rewrite setup, but as we
> do document management, most of the activities our clients are
> involved
> in are about transferring large files both up- and downstream. Could
> such a "large upload" cause such a behaviour? Should I dump the
> apache2
> front controller and get another proxy setup implemented?
>
> By the way which information in the thread dump makes you consider the
> remote server being slow? I'm curious...
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.
Or as you say, if they are processing really large requests, then that
could cause it as well. Either way, that backend system is your
bottleneck, and nothing you do at the glassfish tier is going to help
-- you need to figure out a way to get more data faster out of that
backend system.
-Scott
>
>
>
>> You can add some additional request processing threads for your HTTP
>> service, but that's likely only to make things worse; more requests
>> to your remote system are likely to make that system even slower.
>
> Yes, that is what I had to learn the hard way already, as well... :(
>
> Anyway, thanks again 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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