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Accumulo >> mail # user >> PermGen leak in JBoss

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Re: PermGen leak in JBoss
On Wed, Apr 24, 2013 at 11:21 AM, Heath Abelson

> Hi, I am a colleague of Michael's, I can provide more info
> The following are the 5 threads that are not being cleaned up on an
> undeploy. It's hard to get more stack info than this.
> Daemon Thread [FileWatchdog] (Running)
> Daemon Thread [MSC service thread 1-5-SendThread(cbdbtestbox:2181)]
> (Running)
> Daemon Thread [MSC service thread 1-5-EventThread] (Running)
> Daemon Thread [Thrift Connection Pool Checker] (Running)
> Daemon Thread [FileWatchdog] (Running)
> Using Plumbr, the report states that the SendThread and EventThread above
> both contain an instance of org.apache.zookeeper.ClientCnxn

So two zookeeper threads. An Accumulo thread (Thrift Connection Pool
Checker).  What are the FileWatchdog threads?  Those could be related to
accumulo-start or hdfs.
> -Heath
> -----Original Message-----
> From: Michael Giordano
> Sent: Wednesday, April 24, 2013 9:48 AM
> Subject: PermGen leak in JBoss
> Under version 1.3.7 we are using the following code to initialize a
> cloudbase connection during initialization of our web app:
>                         ZooKeeperInstance instance = new
> ZooKeeperInstance(instanceName, zooKeepers);
>                         connector = instance.getConnector(userId,
> password.getBytes());
> The problem is that under the hood, this call creates several (5) threads
> that are not cleaned up when the app is undeployed in JBoss. This is
> occurring without performing any scans or interacting with cloudbase in any
> other way. After relatively few redeploys of the app, the PermGen Space is
> OOM.
> I can't find any reference in the cloudbase API akin to a close() method
> for the Connector object. This is a classloader leak effecting any webapp
> that is accessing cloudbase directly. The result of this leak is not simply
> orphaned threads, but thousands of classes not gc'd because the classloader
> itself can't be gc'd. This is what is filling up PermGen.
> Has anyone discovered this particular issue? Has anyone discovered a
> solution?
> Thanks,
> Mike G.
> NetCentric Technology, Inc.
> 3349 Route 138, Building A
> Wall, NJ  07719
> Phone: 732-544-0888