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https://issues.apache.org/jira/browse/MAPREDUCE-1434?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12831608#action_12831608
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Owen O'Malley commented on MAPREDUCE-1434:
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One approach might be to have a subclass of InputFormat, such as:
{code}
public abstract class IncrementalInputFormat extends InputFormat {
InputSplit[] getNewInputSplits(JobContext context) throws IOException;
}
{code}
and such input formats return any "new" splits that they have found since the
last time the method was called.
> Dynamic add input for one job
> -----------------------------
>
> Key: MAPREDUCE-1434
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-1434
> Project: Hadoop Map/Reduce
> Issue Type: New Feature
> Environment: 0.19.0
> Reporter: Xing Shi
>
> Always we should firstly upload the data to hdfs, then we can analize the
> data using hadoop mapreduce.
> Sometimes, the upload process takes long time. So if we can add input during
> one job, the time can be saved.
> WHAT?
> Client:
> a) hadoop job -add-input jobId inputFormat ...
> Add the input to jobid
> b) hadoop job -add-input done
> Tell the JobTracker, the input has been prepared over.
> c) hadoop job -add-input status jobid
> Show how many input the jobid has.
> HOWTO?
> Mainly, I think we should do three things:
> 1. JobClinet: here JobClient should support add input to a job, indeed,
> JobClient generate the split, and submit to JobTracker.
> 2. JobTracker: JobTracker support addInput, and add the new tasks to the
> original mapTasks. Because the uploaded data will be
> processed quickly, so it also should update the scheduler to support pending
> a map task till Client tells the Job input done.
> 3. Reducer: the reducer should also update the mapNums, so it will shuffle
> right.
> This is the rough idea, and I will update it .
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