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From Mitch Granger <mitch.gran...@sophos.com>
Subject Re: Out of Memory on 5.3
Date Tue, 27 Oct 2009 21:27:20 GMT
This is what we've done to tune so far:

  - UseDedicatedTaskRunner=false
  - flow control is off
  - stomp transport uses transport.closeAsync=false

I agree that it is because of the high number of open/close connections 
from Stomp.  When we monitor through JConsole we can see more threads 
starting up for each new connection.  The problem is that these threads 
don't get let go.  Even though the stomp clients are disconnecting the 
number of threads that get released is less than the number created.  So 
  the thread count goes up and up until it fails.  All of the above 
settings/tuning only delay when it will hit the wall.

Dejan Bosanac wrote:
> Hi Mitch,
> 
> I think the root cause of this problem is that you probably have Stomp
> clients that open/close connection at a high rate. I simulated this problem
> on OSX with a StompLoadTest (
> http://svn.apache.org/viewvc/activemq/trunk/activemq-core/src/test/java/org/apache/activemq/transport/stomp/StompLoadTest.java?view=log),
> while trying to reproduce "too many open files" problem. You can find some
> of my findings (and workaround) in this thread.
> 
> http://www.nabble.com/%22too-many-open-files%22-error-with-5.3-and-Stomp-tt25888831.html#a26010080
> 
> (BTW. it is producing "too many open files" problem on linux) Basically, the
> problem with stomp is that every send is done in separate connection and
> thus considered to be a new producer for every message. So when producer
> flow control is hit, the producers are piling up and probably not releasing
> connections. Thus you can observe large number of tcp connections on the
> system in state TIME_WAIT (and TIME_CLOSE), which causes that the system
> limit is hit at one point. In the above thread, you can find a workaround
> that worked for me for that test. I started investigating this more and
> hopefully I'll have some more findings in the near future.
> 
> Cheers
> --
> Dejan Bosanac - http://twitter.com/dejanb
> 
> Open Source Integration - http://fusesource.com/
> ActiveMQ in Action - http://www.manning.com/snyder/
> Blog - http://www.nighttale.net
> 
> 
> On Tue, Oct 27, 2009 at 1:07 AM, Mitch Granger <mitch.granger@sophos.com>wrote:
> 
>> Update: We've [nearly] proven that this only happens with AMQ running on
>> openVZ.  What exactly is causing it, we're still not sure.  After
>> memoryUsage is met, the number of threads skyrockets until we get
>> OutOfMemoryError.
>>
>> It works just fine on regular hardware; We're going to try VMWare tomorrow.
>>
>> One thing really worth mentioning is that by using the fileCursor we
>> actually started seeing it use the Temp Store.  When reading about
>> systemUsage it is NOT intuitive that the Temp Store does not come into play
>> with the default cursor.  Anyone keeping a significant volume of messages on
>> their queues should be well served by changing the cursor.
>>
>>
>> Mitch Granger wrote:
>>
>>> Config is attached.  We have also tried the activemq-scalability.xml with
>>> the only change being adding a stomp connector.
>>>
>>> Once we hit the memoryUsage limit we can [sometimes] connect new consumers
>>> but nothing comes back after we send the SUBSCRIBE frame.
>>>
>>> I expect sending to fail when we hit this limit but if we can't subscribe
>>> there's no chance of recovering from this state.
>>>
>>> Rob Davies wrote:
>>>
>>>> On 26 Oct 2009, at 17:38, themitchy wrote:
>>>>
>>>>  We're using only persistent messages and heap size is set to 2GB yet  we
>>>>> hit
>>>>> the memoryUsage limit quite quickly (system usage config below).  This
>>>>> is
>>>>> followed by "java.lang.OutOfMemoryError: unable to create new native
>>>>>  thread"
>>>>> as the process quickly reaches the 2GB of heap we gave it.  How are we
>>>>> getting to that point with the memoryUsage limit set far below it?
>>>>>
>>>>> Is there no way to get AMQ to gracefully limit it's memory usage?
>>>>>
>>>>>       <systemUsage>
>>>>>           <systemUsage>
>>>>>               <memoryUsage>
>>>>>                   <memoryUsage limit="256 mb"/>
>>>>>               </memoryUsage>
>>>>>               <storeUsage>
>>>>>                   <storeUsage limit="60 gb" name="foo"/>
>>>>>               </storeUsage>
>>>>>               <tempUsage>
>>>>>                   <tempUsage limit="60 gb"/>
>>>>>               </tempUsage>
>>>>>           </systemUsage>
>>>>>       </systemUsage>
>>>>>
>>>>> --
>>>>> View this message in context:
>>>>> http://www.nabble.com/Out-of-Memory-on-5.3-tp26064098p26064098.html
>>>>> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>>>>>
>>>>>
>>>> Can you send the rest of your config ?
>>>>
>>>> Rob Davies
>>>> http://twitter.com/rajdavies
>>>> I work here: http://fusesource.com
>>>> My Blog: http://rajdavies.blogspot.com/
>>>> I'm writing this: http://www.manning.com/snyder/
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>

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