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From Craig Muchinsky <>
Subject Re: Java Process Memory Leak
Date Tue, 18 Mar 2014 13:26:22 GMT
Hi Young,

You are correct, I didn't catch that you were using 1.0.0 during my first 
read. I submitted GIRAPH-871 for the netty 4 specific problem I found 
against the 1.1.0-SNAPSHOT code.

Craig M.

From:   Young Han <>
Date:   03/17/2014 05:36 PM
Subject:        Re: Java Process Memory Leak

Interesting find.. It looks that bit was added recently ( and so was not part of Giraph 
1.0.0 as far as I can tell.

Also, if anyone cares, a clunky (Ubuntu) workaround I'm using is: kill 
$(ps aux | grep "[j]obcache/job_[0-9]\{12\}_[0-9]\{4\}/" | awk '{print 


On Mon, Mar 17, 2014 at 6:10 PM, Craig Muchinsky <> 
I just noticed a similar problem myself. I did a thread dump and found 
similar netty client threads lingering. After poking around the source a 
bit, I'm wondering if the problem is related to this bit of code I found 
in the NettyClient.stop() method: 

            if (executionGroup != null) { 

Notice that the first await termination call seems to be waiting on the 
executionGroup instead of the workerGroup... 

Craig M. 

From:        Young Han <> 
Date:        03/17/2014 03:25 PM 
Subject:        Re: Java Process Memory Leak 

Oh, I see. I did jstack on a cluster of machines and a single machine... 
I'm not quite sure how to interpret the output. My best guess is that 
there might be a deadlock---there's just a bunch of Netty threads waiting. 
The links to the jstack dumps:     (PageRank, single worker, amazon0505 
graph from SNAP)   (MST, from one of the 64 workers, com-orkut 
graph from SNAP)

Any idea what's happening? Or anything in particular I should look for 


On Mon, Mar 17, 2014 at 12:19 PM, Avery Ching <> wrote: 
Hi Young,

Our Hadoop instance (Corona) kills processes after they finish executing 
so we don't see this.  You might want to do a jstack to see where it's 
hung up on and figure out the issue.



On 3/17/14, 7:56 AM, Young Han wrote: 
Hi all,

With Giraph 1.0.0, I've noticed an issue where the Java process 
corresponding to the job loiters around indefinitely even after the job 
completes (successfully). The process consumes memory but not CPU time. 
This happens on both a single machine and clusters of machines (in which 
case every worker has the issue). The only way I know of fixing this is 
killing the Java process manually---restarting or stopping Hadoop does not 

Is this some known bug or a configuration issue on my end?


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