APACHE-HADOOP-DEVELOPER Online Practice Questions and Answers

MapReduce v2 (MRv2/YARN) is designed to address which two issues?

A. Single point of failure in the NameNode.

B. Resource pressure on the JobTracker.

C. HDFS latency.

D. Ability to run frameworks other than MapReduce, such as MPI.

E. Reduce complexity of the MapReduce APIs.

F. Standardize on a single MapReduce API.

What is the term for the process of moving map outputs to the reducers?

A. Reducing

B. Combining

C. Partitioning

D. Shuffling and sorting

What data does a Reducer reduce method process?

A. All the data in a single input file.

B. All data produced by a single mapper.

C. All data for a given key, regardless of which mapper(s) produced it.

D. All data for a given value, regardless of which mapper(s) produced it.

Workflows expressed in Oozie can contain:

A. Sequences of MapReduce and Pig. These sequences can be combined with other actions including forks, decision points, and path joins.

B. Sequences of MapReduce job only; on Pig on Hive tasks or jobs. These MapReduce sequences can be combined with forks and path joins.

C. Sequences of MapReduce and Pig jobs. These are limited to linear sequences of actions with exception handlers but no forks.

D. Iterntive repetition of MapReduce jobs until a desired answer or state is reached.

Which TWO of the following statements are true regarding Hive? Choose 2 answers A. Useful for data analysts familiar with SQL who need to do ad-hoc queries

B. Offers real-time queries and row level updates

C. Allows you to define a structure for your unstructured Big Data

D. Is a relational database

You use the hadoop fs –put command to write a 300 MB file using and HDFS block size of 64 MB. Just after this command has finished writing 200 MB of this file, what would another user see when trying to access this life?

A. They would see Hadoop throw an ConcurrentFileAccessException when they try to access this file.

B. They would see the current state of the file, up to the last bit written by the command.

C. They would see the current of the file through the last completed block.

D. They would see no content until the whole file written and closed.

Assuming default settings, which best describes the order of data provided to a reducer's reduce method:

A. The keys given to a reducer aren't in a predictable order, but the values associated with those keys always are.

B. Both the keys and values passed to a reducer always appear in sorted order.

C. Neither keys nor values are in any predictable order.

D. The keys given to a reducer are in sorted order but the values associated with each key are in no predictable order

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.

A NameNode in Hadoop 2.0 manages ______________.

A. Two namespaces: an active namespace and a backup namespace

B. A single namespace

C. An arbitrary number of namespaces

D. No namespaces

Consider the following two relations, A and B.

A Pig JOIN statement that combined relations A by its first field and B by its second field would produce what output?

A. 2 Jim Chris 2 3 Terry 3 4 Brian 4

B. 2 cherry 2 cherry 3 orange 4 peach

C. 2 cherry Jim, Chris 3 orange Terry

4 peach Brian

D. 2 cherry Jim 2 2 cherry Chris 2 3 orange Terry 3 4 peach Brian 4