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From Grzegorz Kossakowski <>
Subject Re: Javaflow - major memory issue
Date Mon, 17 Mar 2008 18:44:36 GMT
Hello Footh,

footh pisze:
> I've been trying to track down a memory problem with
> my Cocoon application for a long time now.  After a
> period of time, maybe a week or two, the application
> would die with an OutOfMemory error.  I've tried
> increasing the VM memory for the servlet container
> (using Tomcat 5.5) and switching to the JRockIt VM
> (delayed the OOM error, but still got it).  Nothing
> seemed to work.  Finally, I put my app through a
> series of tests to narrow down the culprit.
> After stripping layer upon layer of functionality, I
> finally discovered that Javaflow seems to be the
> problem.  I started with a bare-bones site and drilled
> it with a load tester.  The Tomcat memory use would
> remain stable.  I added more features and still no
> problem.  Then, I threw in the Javaflow, and the
> memory skyrocketed.  To make sure it wasn't something
> I was doing in the Javaflow, I created the simplest
> flow possible - a one-line "sendPage(uri)" call. 
> Still the memory would blow up.
> As a final test, to make sure it wasn't something I
> was doing wrong, I ran the test on the sample Javaflow
> application that comes with Cocoon.  I used the
> calculator sample and just hit the first page.  Once
> again, the memory kept rising.  If I took that page
> off the test, there were no memory issues.
> My next step was to profile the memory use to see if I
> could find out where the memory was being allocated. 
> It turns out that byte array data comprised the
> majority of the allocated memory. After running a test
> for 20 minutes or so, the Tomcat memory use was around
> 1GB with byte array data responsible for 82% of the
> total.
> Now, I realize that Javaflow is considered an unstable
> block.  I'm wondering if anyone else using this
> feature has had similar problems?  Any idea why this
> might be occurring with Javaflow?  Does flowscript
> have similar problems?
> I now need to reconsider the MVC architecture of my
> application which has been in production for several
> years.  I do a lot of stuff in the Javaflow.  I'm open
> to any suggestions!

I don't much details about javaflow internals but basic questions come to my mind:
1. Have you checked what bit of code creates these byte arrays?
2. What's stored in them?

I suggest to create an issue in JIRA and provide answers to these basic questions so devs
can have a 
look and help you. If I was you I would investigate further a little bit before dropping Javaflow

because it may turn out to be really simple problem...

Grzegorz Kossakowski

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