Q.1
The Mapper implementation processes one line at a time via _________ method.
  • a) map
  • b) reduce
  • c) mapper
  • d) reducer
Q.2
Point out the correct statement.
  • a) Mapper maps input key/value pairs to a set of intermediate key/value pairs
  • b) Applications typically implement the Mapper and Reducer interfaces to provide the map and reduce methods
  • c) Mapper and Reducer interfaces form the core of the job
  • d) None of the mentioned
Q.3
The Hadoop MapReduce framework spawns one map task for each __________ generated by the InputFormat for the job.
  • a) OutputSplit
  • b) InputSplit
  • c) InputSplitStream
  • d) All of the mentioned
Q.4
Users can control which keys (and hence records) go to which Reducer by implementing a custom?
  • a) Partitioner
  • b) OutputSplit
  • c) Reporter
  • d) All of the mentioned
Q.5
Point out the wrong statement.
  • a) The Mapper outputs are sorted and then partitioned per Reducer
  • b) The total number of partitions is the same as the number of reduce tasks for the job
  • c) The intermediate, sorted outputs are always stored in a simple (key-len, key, value-len, value) format
  • d) None of the mentioned
Q.6
Applications can use the ____________ to report progress and set application-level status messages.
  • a) Partitioner
  • b) OutputSplit
  • c) Reporter
  • d) All of the mentioned
Q.7
The right level of parallelism for maps seems to be around _________ maps per-node.
  • a) 1-10
  • b) 10-100
  • c) 100-150
  • d) 150-200
Q.8
The number of reduces for the job is set by the user via _________
  • a) JobConf.setNumTasks(int)
  • b) JobConf.setNumReduceTasks(int)
  • c) JobConf.setNumMapTasks(int)
  • d) All of the mentioned
Q.9
The framework groups Reducer inputs by key in _________ stage.
  • a) sort
  • b) shuffle
  • c) reduce
  • d) none of the mentioned
Q.10
The output of the reduce task is typically written to the FileSystem via _____________
  • a) OutputCollector.collect
  • b) OutputCollector.get
  • c) OutputCollector.receive
  • d) OutputCollector.put
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