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MapReduce >> mail # dev >> Cyclic dependency in JobControl job DAG


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Re: Cyclic dependency in JobControl job DAG

+1, can you please open a JIRA ticket (at https://issues.apache.org/jira/browse/MAPREDUCE) and attach a patch?

Thanks,
+Vinod

On Jun 25, 2012, at 6:53 AM, Robert Evans wrote:

> I personally think it is useful.  I would say contribute it.
>
> (Moved common-dev to bcc, we try not to cross post on these lists)
>
> --Bobby Evans
>
> On 6/25/12 3:37 AM, "madhu phatak" <[EMAIL PROTECTED]> wrote:
>
> Hi,
> In current implementation of JobControl, whenever there is a cyclic
> dependency between the jobs it throws a Stack overflow exception .
> For example,
>   ControlledJob job1 = new ControlledJob(new Configuration());
> job1.setJobName("job1");
> ControlledJob job2 = new ControlledJob(new Configuration());
> job2.setJobName("job2");
> job1.addDependingJob(job2);
> job2.addDependingJob(job1);
>                JobControl jobControl = new JobControl("jobcontrol");
> jobControl.addJob(job1);
> jobControl.addJob(job2);
> jobControl.run();
>
> throws
>  java.lang.StackOverflowError
> at java.util.ArrayList.get(ArrayList.java:322)
> at
> org.apache.hadoop.mapreduce.lib.jobcontrol.ControlledJob.checkState(ControlledJob.java:295)
>
> Whenever we write complex application, there is always possibility of
> cyclic dependencies.I have written a method which checks for the cyclic
> dependency  upfront and informs it to the user. I want to know from you
> guys, do you think is it a useful feature? If yes I can contribute it as a
> patch.
>
> Regards,
> Madhukara Phatak
> --
> https://github.com/zinnia-phatak-dev/Nectar
>