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From Lukas Sägesser ...@paysol.ch>
Subject Re: mysteriously dying connections (Oracle <-> tomcat)
Date Fri, 22 Jun 2001 09:58:59 GMT
i checked this over and over again. i really do return all the connetions.

----- Original Message -----
From: "Ralph Einfeldt" <ralph.einfeldt@uptime-isc.de>
To: <tomcat-user@jakarta.apache.org>
Sent: Thursday, June 21, 2001 5:30 PM
Subject: AW: mysteriously dying connections (Oracle <-> tomcat)


> It sounds to me like you're not alway returning the
> connection to the pool or not closing the connection.
>
> But this is hard to say without the source of your
> java class.
>
>
> If you use a connection pool where you have
> access to the source code, look if the get and release
> methods can be intrumented in a way to log each
> get and release with the hashcode of the connection.
> Otherwise log each call to get/release in your own code
> or build a wrapper object around the pool that log
> this information before calling the pool method.
>
>
> > -----Ursprüngliche Nachricht-----
> > Von: Lukas Sägesser [mailto:ls@paysol.ch]
> > Gesendet: Donnerstag, 21. Juni 2001 16:38
> > An: tomcat-user@jakarta.apache.org
> > Betreff: mysteriously dying connections (Oracle <-> tomcat)
> >
> >
> > hi all!
> >
> > problem:
> > --------
> >
> > database access is managed via a java class that is
> > instantiated and loaded into each clients session. every
> > PL/SQL function and/or SQL statement a client needs is
> > called in a method of this class.
> > first, a connection is opened, the statement is called,
> > all resultsets and statements are closed and finally the
> > connection is closed. (or returned back to the
> > connection pool if one is used)
> >
> > the driver we use is the Oracle jdbc ThinDriver (jdbc
> > driver type 4). after running the system for several
> > days, dead connections (and as we just discovered, tons
> > of open cursors) pile up.
> > eventually the webserver(tomcat) will crash or just
> > hang.
> > in the process, access gets slower and slower, there may
> > be delays of 3 minutes until the webserver (or, perhaps
> > the database, in which case the webserver would be just
> > waiting for the db..) gives a response.
> > after a restart of the webserver or the database or
> > both, the system runns very well again.
> >
> > we tried several connection pools. with these, there
> > were no delays for getting a connection, but the pool
> > threw timeoutExceptions (i.e. made it visible that there
> > are hanging connections) and after a few hundred
> > timeouts the VM crashed with a stack overflow.
> >
> > the connections seem to get killed/kill themselfes
> > randomly no matter which function was called. we log the
> > methods and statements that were called for the
> > connections that die, but there is just no pattern in
> > it. thats why we dont find the root of the problem.. is
> > it the driver ? the database ? the tomcat ?
> >
> >
> >
> > environment:
> > ----------------
> >
> > Web Server:
> > Suse Linux 7.2
> > Apache Webserver /w Tomcat JSP Engine 3.2 /w SSL
> >
> > DB Server:
> > Suse Linux 7.2
> > Oracle 8i 8.1.7 /w multi-threaded server (MTS)
> >
> > Backup Server:
> > Oracle Shadow server
> >
> >
> >
> > things done:
> > ------------
> >
> > - linux update
> > - apache update
> > - tomcat update
> > - jdbc thin driver update
> > (everywhere the newest version)
> > - tried several connection pools
> >
> >
> >
> > possible changes:
> > -----------------
> >
> > - use OCI drivers instead of thin driver
> > - use J-serv with GNU_jsp instead of tomcat
> >
> >
> >
> >
> > every help is welcome, we're frustrated to no ends.
> > thanks very much in advance!!
> >
> > l.sägesser
> >
> >
>


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