When can a reduce class also serve as a combiner without affecting the output of a MapReduce program?
When can a reduce class also serve as a combiner without affecting the output of a MapReduce
program?
Calling the next () method:
In the reducer, the MapReduce API provides you with an iterator over Writable values. Calling the
next () method:
The NameNode uses RAM for the following purpose:
The NameNode uses RAM for the following purpose:
Determine how many Mappers will run?
Your cluster’s HDFS block size in 64MB. You have directory containing 100 plain text files, each of
which is 100MB in size. The InputFormat for your job is TextInputFormat. Determine how many
Mappers will run?
Which mode of operation in Hadoop allows you to most closely simulate a production cluster while using a singl
You want to run Hadoop jobs on your development workstation for testing before you submit them
to your production cluster. Which mode of operation in Hadoop allows you to most closely simulate
a production cluster while using a single machine?
How many keys will be passed to the reducer?
You have the following key value pairs as output from your Map task:
(The, 1)
(Fox, 1)
(Runs, 1)
(Faster, 1)
(Than, 1)
(The, 1)
(Dog, 1)
How many keys will be passed to the reducer?
All keys used for intermediate output from mappers must do which of the following:
All keys used for intermediate output from mappers must do which of the following:
Which statement is most accurate about the ordering of these values?
In a MapReduce job, the reducer receives all values associated with the same key. Which
statement is most accurate about the ordering of these values?
What is the behavior of the default partitioner?
What is the behavior of the default partitioner?
Which of the following is true?
During the standard sort and shuffle phase of MapReduce, keys and values are passed to
reducers. Which of the following is true?