To use a lava user-defined function (UDF) with Pig what must you do?
A. Define an alias to shorten the function name
B. Pass arguments to the constructor of UDFs implementation class
C. Register the JAR file containing the UDF
D. Put the JAR file into the userandapos;s home folder in HDFS
You write MapReduce job to process 100 files in HDFS. Your MapReduce algorithm uses TextInputFormat: the mapper applies a regular expression over input values and emits key- values pairs with the key consisting of the matching text, and the value containing the filename and byte offset. Determine the difference between setting the number of reduces to one and settings the number of reducers to zero.
A. There is no difference in output between the two settings.
B. With zero reducers, no reducer runs and the job throws an exception. With one reducer, instances of matching patterns are stored in a single file on HDFS.
C. With zero reducers, all instances of matching patterns are gathered together in one file on HDFS. With one reducer, instances of matching patterns are stored in multiple files on HDFS.
D. With zero reducers, instances of matching patterns are stored in multiple files on HDFS. With one reducer, all instances of matching patterns are gathered together in one file on HDFS.
In the reducer, the MapReduce API provides you with an iterator over Writable values. What does calling the next () method return?
A. It returns a reference to a different Writable object time.
B. It returns a reference to a Writable object from an object pool.
C. It returns a reference to the same Writable object each time, but populated with different data.
D. It returns a reference to a Writable object. The API leaves unspecified whether this is a reused object or a new object.
E. It returns a reference to the same Writable object if the next value is the same as the previous value, or a new Writable object otherwise.
Given the following Hive command:
INSERT OVERWRITE TABLE mytable SELECT * FROM myothertable;
Which one of the following statements is true?
A. The contents of myothertable are appended to mytable
B. Any existing data in mytable will be overwritten
C. A new table named mytable is created, and the contents of myothertable are copied into mytable
D. The statement is not a valid Hive command
On a cluster running MapReduce v1 (MRv1), a TaskTracker heartbeats into the JobTracker on your cluster, and alerts the JobTracker it has an open map task slot.
What determines how the JobTracker assigns each map task to a TaskTracker?
A. The amount of RAM installed on the TaskTracker node.
B. The amount of free disk space on the TaskTracker node.
C. The number and speed of CPU cores on the TaskTracker node.
D. The average system load on the TaskTracker node over the past fifteen (15) minutes.
E. The location of the InsputSplit to be processed in relation to the location of the node.
When is the earliest point at which the reduce method of a given Reducer can be called?
A. As soon as at least one mapper has finished processing its input split.
B. As soon as a mapper has emitted at least one record.
C. Not until all mappers have finished processing all records.
D. It depends on the InputFormat used for the job.
You wrote a map function that throws a runtime exception when it encounters a control character in input data. The input supplied to your mapper contains twelve such characters totals, spread across five file splits. The first four file splits each have two control characters and the last split has four control characters.
Indentify the number of failed task attempts you can expect when you run the job with mapred.max.map.attempts set to 4:
A. You will have forty-eight failed task attempts
B. You will have seventeen failed task attempts
C. You will have five failed task attempts
D. You will have twelve failed task attempts
E. You will have twenty failed task attempts
Consider the following two relations, A and B.
What is the output of the following Pig commands?
X = GROUP A BY S1;
DUMP X;
A. Option A
B. Option B
C. Option C
D. Option D
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?
A. Run all the nodes in your production cluster as virtual machines on your development workstation.
B. Run the hadoop command with the -jt local and the -fs file:///options.
C. Run the DataNode, TaskTracker, NameNode and JobTracker daemons on a single machine.
D. Run simldooop, the Apache open-source software for simulating Hadoop clusters.
Given a directory of files with the following structure: line number, tab character, string: Example: 1abialkjfjkaoasdfjksdlkjhqweroij 2kadfjhuwqounahagtnbvaswslmnbfgy 3kjfteiomndscxeqalkzhtopedkfsikj You want to send each line as one record to your Mapper. Which InputFormat should you use to complete
the line: conf.setInputFormat (____.class) ; ?
A. SequenceFileAsTextInputFormat
B. SequenceFileInputFormat
C. KeyValueFileInputFormat
D. BDBInputFormat
