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https://issues.apache.org/jira/browse/HADOOP-1111?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12480848
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David Bowen commented on HADOOP-1111:
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I was questioning the use of DelayQueue because there isn't any delay. The
delayTime in a JobEndStatusInfo is always its creation time, so it is ready as
soon as it is queued.
I don't think that POST is necessarily any more heavyweight than GET. It does
mean that you'd need to switch from doing text substitution for the parameters
to just passing the parameters as HTTP parameters, but that seems simple
enough. I don't know if there is a precedent for using GET in Hadoop to change
server state, but if not it would seem to be a bad idea to set such a precedent
in violation of the convention I cited earlier that is defined in the HTTP spec.
My mistake on the thread termination - I misread the code. It looks fine.
> Job completion notification to a job configured URL
> ---------------------------------------------------
>
> Key: HADOOP-1111
> URL: https://issues.apache.org/jira/browse/HADOOP-1111
> Project: Hadoop
> Issue Type: New Feature
> Components: mapred
> Affects Versions: 0.12.0
> Environment: all
> Reporter: Alejandro Abdelnur
> Attachments: patch-1111.txt, patch-1111.txt, patch-1111.txt
>
>
> Currently clients have to poll the JobTracker to find if a job has completed
> or not.
> When invoking Hadoop from other systems is desirable to have a notification
> mechanism on job completion.
> The notification approach simplifies the client waiting for completion and
> removes load from the JobTracker as polling can be avoided.
> Proposed solution:
> When the JobTracker processes the completion of a job (success and failure)
> if the job configuration has a jobEnd.notificationUrl property it will make a
> HTTP GET request to the specified URL.
> The jobEnd.notificationUrl property may include 2 variables in it '${jobId}'
> and '${jobStatus}'. if they are present, they will be replaced with tehe job
> ID and status of the job and the URL will be invoked.
> Two additional properties, 'jobEnd.retries' and 'jobEnd.retryInterval', will
> indicate retry behavior.
> Not to delay the JobTracker processing while doing notifications, a
> ConsumerProducer Queue will be used to queue up job notification upon
> completion.
> A daemon thread will consume job notifications from the above Queue and will
> make the URL invocation.
> On notification failure, the job notification is queue up again on the
> notification queue.
> The queue will be a java.util.concurrent.DelayQueue. This will make job
> notifications (on retries) to be avaiable on the consumer side only when the
> retry time is up.
> The changes will be done in the JobTracker and in the LocalJobRunner.
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