最新的高品質 Apache-Hadoop-Developer 考試練習題庫

Which process describes the lifecycle of a Mapper?

• A. The TaskTracker spawns a new Mapper to process all records in a single input split.
• B. The JobTracker spawns a new Mapper to process all records in a single file.
• C. The TaskTracker spawns a new Mapper to process each key-value pair.
• D. The JobTracker calls the TaskTracker's configure () method, then its map () method and finally its close () method.

You have just executed a MapReduce job. Where is intermediate data written to after being emitted from the Mapper's map method?

• A. Intermediate data in streamed across the network from Mapper to the Reduce and is never written to disk.
• B. Into in-memory buffers that spill over to the local file system of the TaskTracker node running the Mapper.
• C. Into in-memory buffers on the TaskTracker node running the Mapper that spill over and are written into HDFS.
• D. Into in-memory buffers that spill over to the local file system (outside HDFS) of the TaskTracker node running the Reducer
• E. Into in-memory buffers on the TaskTracker node running the Reducer that spill over and are written into HDFS.

Analyze each scenario below and indentify which best describes the behavior of the default partitioner?

• A. The default partitioner computes the hash of the key and divides that valule modulo the number of reducers. The result determines the reducer assigned to process the key-value pair.
• B. The default partitioner computes the hash of the key. Hash values between specific ranges are associated with different buckets, and each bucket is assigned to a specific reducer.
• C. The default partitioner assigns key-values pairs to reduces based on an internal random number generator.
• D. The default partitioner computes the hash of the value and takes the mod of that value with the number of reducers. The result determines the reducer assigned to process the key-value pair.
• E. The default partitioner implements a round-robin strategy, shuffling the key-value pairs to each reducer in turn. This ensures an event partition of the key space.

Review the following data and Pig code:

What command to define B would produce the output (M,62,95l02) when invoking the DUMP operator on B?

• A. B = JOIN A BY (gender = = 'M' AND zip = = '95102');
• B. B= GROUP A BY (zip = = '95102' AND gender = = 'M');
• C. B = FILTER A BY (zip = = '95102' AND gender = = M");
• D. B= FOREACH A BY (gender = = 'M' AND zip = = '95102');

Which one of the following statements is FALSE regarding the communication between DataNodes and a federation of NameNodes in Hadoop 2.0?

• A. DataNodes send periodic block reports to all the NameNodes.
• B. Each DataNode registers with all the NameNodes.
• C. DataNodes send periodic heartbeats to all the NameNodes.
• D. Each DataNode receives commands from one designated master NameNode.