[Neo4j] Close with running transaction II

Peter Neubauer peter.neubauer at neotechnology.com
Tue Sep 13 18:45:36 CEST 2011


Vaccaro,
can you reliably reproduce this in a unit test? that would be very
helpful in doing something about it!

Cheers,

/peter neubauer

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On Wed, Sep 7, 2011 at 8:34 PM, Vaccaro, Kristen M <kvaccaro at mitre.org> wrote:
> Hi, I'm experiencing the same problem that is mentioned in a thread from a while back on this list (http://lists.neo4j.org/pipermail/user/2011-March/007746.html). This was a case where someone had a thread running when they try to close the database and keeping having a dirty log with "INFO: Close invoked with 1 running transaction(s)". As far as I know I close every transaction I open. The response to the other poster was that there is no way to force all transactions to end before shutting down -- which leaves me with the question: what are the risks of leaving the code as is? And what are the best practices to avoid this problem? (again, as far as I can see all transactions are ended).
> Thanks,
> Kristen
>
> -----Original Message-----
> From: user-bounces at lists.neo4j.org [mailto:user-bounces at lists.neo4j.org] On Behalf Of Nuo Yan
> Sent: Wednesday, September 07, 2011 2:12 PM
> To: Neo4j user discussions
> Subject: Re: [Neo4j] Server couldn't start after java.lang.OutOfMemoryError
>
>
> According to this: http://neo4j.org/forums/#nabble-td3248377, I upgraded to 1.4.1 and the problem goes away.
>
> I guess there must be a bug in the 1.4.0 REST API that leaks classloader memory or so, and GC didn't happen as expected in PermGen. Anyways, it looks great after upgrading to 1.4.1. Memory monitoring graph shows GC happens as desired in PermGen.
>
> Thank you!
>
> On Sep 6, 2011, at 11:30 PM, Nuo Yan wrote:
>
>> Hey Adriano and everyone,
>>
>> I finally got a chance to monitor/profile the neo4j process with VisualVM when I run my set of tests.
>>
>> It seems that after running the set of tests once, ~ 50M of PermGen was used. However, subsequent test runs simply multiples that, which worries me a little. After the fourth run of the tests, ~ 200M of PermGen space was used.
>>
>> My app accesses to neo4j completely using the REST interface. During the test run, new nodes and relationships are  being frequently created. There are batch requests that performs multiple actions at once (number of actions is reasonable, really small in this case, usually a few, or tenth). There are also gremlin script executions through REST (send the gremlin query over to the server through REST API). Most of the gremlin queries are traversals and returns the vertices or edges match the constraints.
>>
>> Total number of nodes created during a test run is only hundreds. There are more relationships, but at most thousands.
>>
>> That's basically all of the things that are done against neo4j server during a test run. Given this, do you think the PermGen usage is reasonable? Or do you think something is very wrong? I worried that setting a larger PermGen would only postpone but not resolve the OutOfMemory problem.
>>
>> Let me know if any other info is needed.
>>
>> Thanks much,
>> Nuo
>>
>>
>>
>>
>> On Aug 29, 2011, at 6:09 AM, Adriano Henrique de Almeida wrote:
>>
>>> Hi Nuo, any results here?
>>>
>>> Cheers
>>>
>>> 2011/8/26 Nuo Yan <yan.nuo at gmail.com>
>>>
>>>> Hey Adriano,
>>>>
>>>> Thanks very much for your reply. I will try with MaxPermSize.
>>>>
>>>> It's on my local machine, we are evaluating Neo4j and do not have it on
>>>> production yet. I'm accessing the server through the REST APIs, the app is
>>>> separate from Neo. I will see if I can do some profiling on Neo when I run
>>>> my tests.
>>>>
>>>> Thanks,
>>>> Nuo
>>>>
>>>>
>>>>
>>>> On Fri, Aug 26, 2011 at 3:53 PM, Adriano Henrique de Almeida <
>>>> adrianoalmeida7 at gmail.com> wrote:
>>>>
>>>>> Hey Nuo,
>>>>>
>>>>> wrapper.java.maxmemory and Xmx won't help, since it is a PermGenSpace
>>>>> problem, and they only deal with HeapSpace. Did you try with:
>>>>> -XX:*MaxPermSize
>>>>> **?*
>>>>>
>>>>> Anyway, something very wrong is happening, since you have few nodes.
>>>>>
>>>>> It is happening only on production, or development also? If it is
>>>> happening
>>>>> on development, try to isolate the situation where you're stucking the
>>>>> permgen. Run you app with VisualVM, for instance, or any other profiler.
>>>>> Aren't you dealing with classloaders on your app?
>>>>>
>>>>> Cheers
>>>>>
>>>>> Adriano Almeida
>>>>>
>>>>>
>>>>>
>>>>> 2011/8/26 Jim Webber <jim at neotechnology.com>
>>>>>
>>>>>> Hi Nuo,
>>>>>>
>>>>>> if you're using Neo4j server then you can edit the value in
>>>>>> conf/neo-wrapper.conf
>>>>>>
>>>>>> wrapper.java.maxmemory=1024
>>>>>>
>>>>>> Jim
>>>>>> _______________________________________________
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>>>>>> User at lists.neo4j.org
>>>>>> https://lists.neo4j.org/mailman/listinfo/user
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Adriano Almeida
>>>>> Caelum | Ensino e Inovação
>>>>> www.caelum.com.br
>>>>> _______________________________________________
>>>>> Neo4j mailing list
>>>>> User at lists.neo4j.org
>>>>> https://lists.neo4j.org/mailman/listinfo/user
>>>>>
>>>> _______________________________________________
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>>>
>>>
>>>
>>> --
>>> Adriano Almeida
>>> Caelum | Ensino e Inovação
>>> www.caelum.com.br
>>> _______________________________________________
>>> Neo4j mailing list
>>> User at lists.neo4j.org
>>> https://lists.neo4j.org/mailman/listinfo/user
>>
>
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