Will Du
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Will Du
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CCD-410 Warm-up

Question 1 of 2

1

You have a large dataset of key value pairs, where the keys are strings and the values are the integers. For each unique key, you want to identify the largest integer. In writing a MapReduce program to accomplish this, can you take advantage of a combiner?

Select one of the following:

  • No, a combiner would not be useful in this case.

  • Yes.

  • Yes, but the number of unique keys must be known in advance.

  • Yes, as long as all the keys fit into memory on each node.

  • Yes, as long as all the integer values that share the same key fit into memory on each node.

Explanation

Question 2 of 2

1

Given the following code from a MapReduce application:
Job job = new Job(getConf(), "MyMapReduceJob");
Path in = new Path(“source1”, “source2”);
Path out = new Path(“dest1”);
FileInputFormat.setInputPaths(job, in);
FileOutputFormat.setOutputPath(job, out);

Which one of the following statements is true?

Select one of the following:

  • The input for this job will be the contents of the source1/source2 folder

  • The input for this job will be the contents of both the source1 and source2 files

  • The input of this job cannot be determined by the code above

  • The output of this job will be the source1/source2 folder

Explanation