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Hadoop, mail # general - Child processes on datanodes/task trackers


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Re: Child processes on datanodes/task trackers
Ted Yu 2010-08-26, 03:39
I don't use ehcache.
Did you forget to close CacheManager at the end of your job by any chance ?

On Wed, Aug 25, 2010 at 7:59 PM, C J <[EMAIL PROTECTED]> wrote:

> Thanks Ted!
>
> I did a jstack and it seems there is an issue with ehcache that I am using
> in
> the mapper task.
>
>
> "net.sf.ehcache.CacheManager@57ac3379" daemon prio=10
> tid=0x0000000059180800
> nid=0x379e in Object.wait() [0x0000000041506000]
>   java.lang.Thread.State: TIMED_WAITING (on object monitor)
>        at java.lang.Object.wait(Native Method)
>        - waiting on <0x00002aaabb0b89a8> (a java.util.TaskQueue)
>        at java.util.TimerThread.mainLoop(Timer.java:509)
>        - locked <0x00002aaabb0b89a8> (a java.util.TaskQueue)
>        at java.util.TimerThread.run(Timer.java:462)
>
>   Locked ownable synchronizers:
>        - None
> .
> .
> .
>
>
> The hadoop version I am using is 0.20.2.
>
> Thanks.
>
>
>
> ________________________________
> From: Ted Yu <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED]
> Sent: Wed, August 25, 2010 7:34:35 PM
> Subject: Re: Child processes on datanodes/task trackers
>
> After you obtain pid, you can use jstack to see what the Child process was
> doing.
>
> What hadoop version are you using ?
>
> On Wed, Aug 25, 2010 at 7:28 PM, C J <[EMAIL PROTECTED]> wrote:
>
> > Thanks for your reply.
> >
> > Some of these child tasks belong to successful jobs. I am wondering why
> > they are
> > still hanging there for long finished jobs.
> >
> >
> >
> >
> >
> > ________________________________
> > From: Ted Yu <[EMAIL PROTECTED]>
> > To: [EMAIL PROTECTED]
> > Sent: Wed, August 25, 2010 4:17:38 PM
> > Subject: Re: Child processes on datanodes/task trackers
> >
> > Use jps to find out pid of the Child.
> > Then use this to find out which job the Child belongs to:
> > ps aux | grep <pid>
> >
> > On Wed, Aug 25, 2010 at 12:20 PM, C J <[EMAIL PROTECTED]> wrote:
> >
> > > Hi,
> > >
> > > I wanted to know why I see running Child processes on my datanodes even
> > > though
> > > there is no job running at that time. Are these left over from failed
> > > attempts?
> > >
> > > Is there anything I can do to keep these clean?
> > >
> > > Thanks,
> > > Deepika
> > >
> > >
> > >
> >
> >
> >
> >
> >
>
>
>
>
>