Which of the following writables can be used to know value from a mapper/reducer?
Nullwritable
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IntWritable
Text
None of the Option is Correct
Category: Hadoop MapReduce
Distributed cache files can’t be accessed in Reducer.
Distributed cache files can’t be accessed in Reducer.
FALSE
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TRUE
Some
None of the Option is Correct
Which of the following class is responsible for converting inputs to key-value (c) Pairs of Map Reduce?
Which of the following class is responsible for converting inputs to key-value (c) Pairs of Map Reduce
RecordReader
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InputSplit
FileInputFormat
Mapper
What should be an upper limit for counters of a Map Reduce job?
What should be an upper limit for counters of a Map Reduce job?
~50
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~150
~15
~5s
Which of the following type of joins can be performed in Reduce side join operation?
Which of the following type of joins can be performed in Reduce side join operation?
All Options are Correct
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Left Outer Join
Right Outer Join
Full Outer Join
Number of mappers is decided by the
Number of mappers is decided by the
Input Splits
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Available heap memory
Available Mapper slots
Mappers specified by the programmer
Reduce side join is useful for
Reduce side join is useful for
Very large datasets
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Very small data sets
One small and other big data sets
One big and other small datasets
Which of the following operations can’t use Reducer as combiner also?
Which of the following operations can’t use Reducer as combiner also?
Group by Average
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Group by Count
Group by Minimum
Group by Maximum
Point out the wrong statement.
Point out the wrong statement.
Reducer has 2 primary phases
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Increasing the number of reduces increases the framework overhead, but increases load balancing and lowers the cost of failures
It is legal to set the number of reduce-tasks to zero if no reduction is desired
The framework groups Reducer inputs by keys (since different mappers may have output the same key) in the sort stage
Point out the correct statement.
Point out the correct statement.
All Options are Correct
Excellent ! Your Answer is Correct. Explanation: Reporters can be used to set application-level status messages and update Counters.
Applications can use the Reporter to report progress
The Hadoop MapReduce framework spawns one map task for each InputSplit generated by the InputFormat for the job
The intermediate, sorted outputs are always stored in a simple (key-len, key, value-len, value) format