Question : Using Hadoop mapreduce framework, you have to use org.apache.hadoop.mapred.lib.IdentityMapper java class as a Mapper and /bin/wc as a reducer. Select the correct option from below command.
Correct Answer : Get Lastest Questions and Answer : Explanation: You can supply a Java class as the mapper and/or the reducer. The above example is equivalent to:
Correct Answer : Get Lastest Questions and Answer : Explanation: User can specify stream.non.zero.exit.is.failure as true or false to make a streaming task that exits with a non-zero status to be Failure or Success respectively. By default, streaming tasks exiting with non-zero status are considered to be failed tasks.
Question : You have written your Python code as a Mapper for MapReduce job in a file called "myPythonScript.py". To run MapReduce job, You have to transfer this Python file on each node of the cluster, before starting job. 1. True 2. False
Correct Answer : Get Lastest Questions and Answer : Explanation: You can specify any executable as the mapper and/or the reducer. The executables do not need to pre-exist on the machines in the cluster
1. Increase the block size on all current files in HDFS. 2. Increase the block size on your remaining files. 3. Access Mostly Uused Products by 50000+ Subscribers 4. Increase the amount of memory for the NameNode. 5. Increase the number of disks (or size) for the NameNode.
1. It returns a reference to a different Writable object time. 2. It returns a reference to a Writable object from an object pool. 3. Access Mostly Uused Products by 50000+ Subscribers 4. It returns a reference to a Writable object. The API leaves unspecified whether this is a reused object or a new object. 5. 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.
Question : For each input key-value pair, mappers can emit: 1. As many intermediate key-value pairs as designed. There are no restrictions on the types of those key-value pairs (i.e., they can be heterogeneous). 2. As many intermediate key-value pairs as designed, but they cannot be of the same type as the input key-value pair. 3. Access Mostly Uused Products by 50000+ Subscribers 4. One intermediate key-value pair, but of the same type. 5. As many intermediate key-value pairs as designed, as long as all the keys have the same types and all the values have the same type.