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From footh <fo...@yahoo.com>
Subject Re: Javaflow - major memory issue: 2109 patch results
Date Tue, 18 Mar 2008 19:32:14 GMT
Ok, so I applied the patch supplied by cocoon-2109.  The results appear to be the same.  After
10K
samples from the load tester, the tomcat memory was virtually identical from before and after
the
patch.  Then, I ran the load tester with the profiler attached.  With the slower page response
time (due to the profiler) the memory *seemed* to move up slower with the new code but that
is by
no means a scientific obeservation.  In the end, the memory still increased.

Upon examining the profiler data, there was a difference however.  Instead of the
ContinuationsManagerImpl (CMI) having the greatest retained size, it was a bunch of HashMap
objects at the top of the list.  The one CMI object was in second place (63% on this run)
but
about 19K HashMap objects were responsible for 92%.  I assume this is because the patch changes
a
variable in CMI to a HashMap and so the retained size of the CMI object gets lopped into the
HashMap objects whereas pre-patch this wasn't the case.

The real question I have is, why is the CMI object retained size so large?  As the load testing
continues, the memory retained by CMI dominates the rest of the objects.  If the load stops,
it is
eventually cleaned up, but by then it may be too late.

If there are any other suggestions, I'm willing to put more effort into figuring this out.


--- footh <footh@yahoo.com> wrote:

> Ok, I'll give the patch a shot.
> 
> I'm using Tomcat version 5.5.26.  Concerning the
> store-janitor values, I haven't changed them from the
> default.
> 
> In fact, as I stated in my first post, the problem
> occurs even on the sample javaflow calculator
> application (relative url: 
> /cocoon/samples/blocks/javaflow/calculator.do).  Try
> hitting that page a bunch of times with a load tester.
> 
> 
> --- Antonio Gallardo <agallardo@agssa.net> wrote:
> 
> > Hi footh,
> > 
> > Testing the patch is a good start. Would you provide
> > tomcat version and 
> > the parameters you use to start it?
> > 
> > How do you configure cocoon.xconf, in special the
> > values for:
> > 
> > <store-janitor logger="core.store.janitor"/>?
> > 
> > Best Regards,
> > 
> > Antonio Gallardo.
> > 
> > footh escribió:
> > > Thanks for all the replies.  I did some more
> > digging
> > > into the profiling data.  It turns out that the
> > > ContinuationsManagerImpl is at the top of the
> > object
> > > path of the byte arrays where 
> > >
> >
> org.apache.cocoon.environment.util.BufferedOutputStream
> > > is the actual parent of the arrays.
> > >
> > > Looking down the path, I can see the TreeSet and
> > > SortedSet that is mentioned in cocoon-2109.  I
> > would
> > > say this issue is a likely cause for the memory
> > > ballooning.
> > >
> > > The load tester is simulating 5 users staggered 10
> > > seconds apart and only hitting a couple very
> > simple
> > > pages.  Yet within 15 minutes, the Tomcat memory
> > use
> > > approaches 1GB.  After stopping the load tester
> > and
> > > examining the memory, I did notice in the profiler
> > > that the byte arrays eventually cleaned up. 
> > However,
> > > looking at the Task Manger (using Windows), Tomcat
> > was
> > > still holding the full amount of memory from when
> > I
> > > stopped the load tester, ie. it didn't go down
> > when
> > > the  byte arrays cleaned up.
> > >
> > > I suppose the next step is to try the patch
> > provided
> > > in  2109.  Any other suggestions?
> > >
> > >   
> > 
> >
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> > 
> 
> 
> 
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