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From "Breno Jacinto" <>
Subject Re: Hundreds of Instances
Date Tue, 04 Dec 2007 00:42:00 GMT
Hi Christopher,

2007/12/3, Christopher Schultz <>:

> You are probably seeing 170 threads, not 170 Tomcat instances.

    Yes, you're right. I used instances because thats what tomcat says
when it's shutting down.

> Tomcat itself is extremely stable. This is most likely an application
> problem. Perhaps your application does well with little traffic but does
> not scale well. You got a burst of traffic and everything fell apart. ??

    Not really. I dont have the exact numbers, but I think we'd get at
most 50 users every 10 minutes = 5 users / min. I believe that´s
pretty low.

    I already had several memory problems with BDB XML - thought I had
hunted them down, but now I start to have the same problems. I don't
think it's related to the fact that searches are returned to
ArrayLists, which are pretty common operations and we get bigger
results with time - I assume the garbage collector cleans them all.
But BDB XML works with bindings for Java, and so there's a lot of
memory allocation issues.

> If Tomcat isn't crashing, then everything should be fine. If you are
> getting OOMEs, then you need to find out what's causing you to run out
> of memory. Several memory profilers are mentioned on this list all the
> time. It's also not a bad idea to have the JVM record a thread dump to
> stdout whenever an OOME occurs. You can find all of this information in
> the list archives or google.

     Yeah, its not crashing. Nor the JVM either. They get very, very
slow because Linux starts to swap like crazy, after the Tomcat process
eats almost 100% of RAM. I'm pretty sure it´s not a burst, but
something that progressively gets allocated and not deallocated. I'm
not sure why, but thanks for the idea of the profiler. I'll dig for

> - -chris

best regards,

:: Breno Jacinto ::
:: breno - at - ::
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