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From Dejan Bosanac <de...@nighttale.net>
Subject Re: Out of Memory on 5.3
Date Tue, 27 Oct 2009 12:27:47 GMT
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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