- The memory that a vm uses is never decreasing (At least I don't
know any that behave that way)
To understand that you have to see two different things:
- the memory that is used by the vm
- the memory inside the vm
All vm's that I know, don't return memory to the os. What
happens during a gc is just that inside the vm the memory is
marked as free. So the only save indicators for the question
'how many memory is currently in use' are the methods
java.lang.Runtime.get*Memory.
- To a certain degree it is normal that the memory is increasing.
Reasons for that:
- each session needs some memory, that is only released after
the session has timed out. If you create sessions very fast
this can consume quite some memory. (If you are creating
the sessions faster as they dye tomcat will die with an out
of memory error.)
- Just because an object isn't used anymore , is dosn't mean
that the memory that is consumed by it is freed. This just
happens, when the garbage collector runs. When this will
happen, is up to the VM. Until then the memory will grow.
There is nothing you (or tomcat) can do about that from
inside the application. The only action that has affect,
is to play with the various parameters for the garbage
collector as argument to the java process.
So what can you do, to track the problem down:
- Make shure that the request don't create new sessions.
(There are several routes how to achieve that)
- Strip the page that you test down to a minmal jsp.
(I haven't seen in your previous posts that
you say anything about the nature of this page)
- Track the memory usage with java.lang.Runtime.get*Memory()
- Use the java options to achieve a verbose gc
- Set the maximal heap size to a lower bound, to see
what happens when this value is reached.
- Profile the application with OptimizeIt or jProbe
or any other profiler.
- show us your page, maybe it's the page that contains the
memory leak
Sun has some background and advice at:
http://java.sun.com/docs/hotspot/gc/
http://java.sun.com/products/hotspot/whitepaper.html
Also javaworld:
http://www.javaworld.com/javaworld/jw-01-2002/jw-0111-hotspotgc.html
Ralph Einfeldt
Uptime Internet Solution Center GmbH
Hamburg, Germany
Hosting, Content Management, Java Consulting
http://www.uptime-isc.de
> -----Urspr�ngliche Nachricht-----
> Von: Ing. Damiano Bolla [mailto:[EMAIL PROTECTED]]
> Gesendet: Freitag, 27. September 2002 16:13
> An: Tomcat Users List
> Betreff: RE: Tomcat 4.1.12 memory leak, resources leak, what to do ?
>
>
> Yes, I did let it run and it keeps eating.
>
> As far as I see this IS a problem.
--
To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]>
For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
