[Mulgara-dev] random heap-space exhaustions

Tate Jones tate at bluedog.com.au
Mon Feb 12 20:52:04 UTC 2007



On 12/02/2007, at 10:00 PM, Life is hard, and then you die wrote:

> On Sun, Feb 11, 2007 at 09:25:40AM +1000, Tate Jones wrote:
>> Are you executing the queries via SOAP over HTTP?
>
> Yes.

What type of client is making the requests?
Is the client requesting a new session for every request?  Cookies on?
We had problems VB as it would not handle sessions.  This would  
result in OOM on the server.

>> I would download JProfiler eval and monitor it.  It will give you the
>> answer pretty quickly.
>
> I played with it, but I'm not too happy. Just including the agentlib
> slows down the server by 30%, which isn't too bad I guess. But I
> didn't see any way to run this unattended, except by including some
> code in the webapp to call their API's to do the dumps.

You need to adjust the type of sampling you are doing.  There are  
many options available that can reduce the overhead to about 5%.
I was the original person that performed the performance tuning of  
Kowari with JProfiler.  You can run JProfiler from the commandline  
and remotely connect to it.
You will need to read the instructions on how to detect memory leaks.

I will send you some details on how to do this.

> So, I wrote a small app that uses JMX to monitor the heap usage and
> to get a thread dump and a heap dump (using the jmap API's) when it
> gets too high - nice thing is it has 0 overhead (well, I couldn't
> measure any difference with jmx enabled and this app pinging the
> server every couple seconds, so it's less than 2% or 3%) and I don't
> have to change anything in the server itself apart from an extra
> option on the command line.
>
>
>   Cheers,
>
>   Ronald
>
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Tate Jones
tate at bluedog.com.au





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