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From Peter Lin <>
Subject Re: Memory leaks - large and uncollected
Date Wed, 03 Aug 2005 19:14:32 GMT
I've run optimizeIt on Jmeter about 3 dozen times when I wrote the
various samplers like Webservice, jms, accesslog and tomcat monitor.
Under normal conditions, JMeter's memory usage is constant. I've run
tests using OptimizeIt on JMeter for 500K, 1million and 2 million

what I haven't done is try it on SSL. I believe there's a known bug
with Sun's SSL implementation which results in connections not closing
and resulting in OutOfMemoryException.  The solution to that is to use
HttpClient sampler instead of the default one.

the default http sampler uses the Sun implementation, which I believe
exhibits that behavior. the HttpClient version should perform better.
You can also verify this by using HTTP with the same test instead of
HTTPS. If the bug doesn't appear in non-secure HTTP, it would support
the idea that HTTPS is the cause.

I know that some EJB containers use Sun implementation for SSL/HTTPS
and they exhibit the same exact bug. If those connections are
time_wait and aren't getting cleaned up, it's very likely the known
SSL bug.


On 8/3/05, <> wrote:
> Hi,
> I've created a script which generates thousands of HTTP requests; the
> script seems to work fine, but I'm seeing a large memory leak in JMeter
> itself.  Before you write this off as a "newbie" question, here is
> everything I've tried to do to fix it:
> 1.  Deleting _all_ listeners.  I still see the memory leak, even when
> running without any listeners.
> 2.  Stopping the test and doing "Clear all".  The memory is _not_
> reclaimed, even after a full garbage collection.
> 3.  Increasing the memory available to JMeter to 1GB.  As the test runs,
> the memory usage climbs until its doing continuous full garbage
> collections.  Eventually an OutOfMemory exception occurs.
> 4.  Switching the HTML parser from the default to the RegexpHTMLParser.
> Still see the same memory leak, albeit slower.
> Does this sound familiar to anyone?  It appears to be a slow leak
> per-request.  I'm running XP against an SSL-enabled server.  Does SSL leak
> memory per-connection?  "netstat -n" shows thousands of connections - and
> it looks like they don't go away until JMeter quits.
> I only see the leak if I do on the order of 100,000+ HTTP requests.  I can
> send interested parties the script to test for themselves.  I'm not
> attaching the script now since its 500KB.
> I really need to figure out what is going wrong.  I'm about to attempt to
> run a memory profiler (OptimizeIt) on JMeter to determine where the leak is
> under-the-covers...
> Thanks,
> -Jon Andersen
> The Sakai Project
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