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From "K J.Sreekumar" <k.j.sreeku...@comprotechnologies.com>
Subject Re: Tomcat stops responding
Date Wed, 22 Dec 2010 13:26:39 GMT
Hello All,
Thank you for the suggestions.
We noted that we have these errors in the logs -

SEVERE: The web application [/rel] registered the JBDC driver
[oracle.jdbc.OracleDriver] but failed to unregister it when the web
application was stopped. To prevent a memory leak, the JDBC Driver has been
forcibly unregistered.
Dec 21, 2010 1:41:48 AM org.apache.catalina.loader.WebappClassLoader
clearReferencesThreads
SEVERE: The web application [/rel] appears to have started a thread named
[Thread-7] but has failed to stop it. This is very likely to create a memory
leak.
Dec 21, 2010 1:41:48 AM org.apache.catalina.loader.WebappClassLoader
clearThreadLocalMap
SEVERE: The web application [/rel] created a ThreadLocal with key of type
[org.apache.commons.lang.builder.ReflectionToStringBuilder$1] (value
[org.apache.commons.lang.builder.ReflectionToStringBuilder$1@29fb93]) and a
value of type [java.util.HashSet] (value [[]]) but failed to remove it when
the web application was stopped. This is very likely to create a memory
leak.


The thread dump has been attached with this mail.
Hope these help.

We are now trying to replicate this issue by running tomcat on port 80
(switching off apache httpd).
I'll post the observations here after we do this.

Thanks again
Sreekumar

On Sun, Dec 19, 2010 at 10:57 PM, Konstantin Kolinko <knst.kolinko@gmail.com
> wrote:

> 2010/12/17 K J.Sreekumar <k.j.sreekumar@comprotechnologies.com>:
> > The logs does not show any error.
>
> Do they show anything at all?
>
> > There are only a total of 50-60 threads in the thread dump, mostly in
> WAIT
> > state. Also, it does not show any BLOCKING or LOCKED threads.
>
> It would be interesting to look at the thread dump.
>
> If it is too long for the e-mail, you may post it somewhere else, e.g.
> to a pastebin site.
>
> Your telnet test,
>
> > HTTP/1.1 400 Bad Request
> > Server: Apache-Coyote/1.1
> > Transfer-Encoding: chunked
> > Date: Sat, 18 Dec 2010 09:57:04 GMT
> > Connection: close
>
> shows that Tomcat processes incoming connections (and correctly
> identifies your HTTP/1.1 request as an invalid one). So maybe it is
> only your webapp that fails.
>
> > Memory utilization was 400MB only
> > TOMCAT restart does not fix the problem. The machine needs to be
> restarted
> > to resume normal operation.
>
> 1. Are you sure that restart was successful? I.e., that "stop" part of
> it has actually stopped Tomcat and freed resources.
>
> 2. Maybe there are some external resources (database? exhausting free
> space on a hard drive?)  I wonder what can it be that can be exhausted
> and is not freed by Tomcat shutdown. It is easy to exhaust database
> connections or open file handles, if you do not close them properly,
> but all they should be freed when a Windows application shuts down.
>
> 3. Maybe there is anything in the system Events log.
>
> 4. If you stop and start Tomcat after the failure, are all the usual
> startup time messages present in the logs? Maybe there are some
> messages, like the webapp failing to start.
>
> 5. You may deploy the manager webapp, accessible as
> http://<server>:<port>/manager/html
> It will show you the status of your webapps and the requests that are
> currently being processed.
>
> > Netstat did not reveal any extraneous connections
> >
> > We are running Tomcat 6.0.29 on the following platform -
> > OS: Windows server 2003 R2 Enterprise Edition SP2
> > Hardware: Intel Xeon L5520 2.27 GHz (16 CPU threads )
> > The server.xml we are using has been attached with this mail.
> >
>
> Best regards,
> Konstantin Kolinko
>
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