HDPCD 無料問題集「Hortonworks Data Platform Certified Developer」

（A）Reducers start copying intermediate key-value pairs from each Mapper as soon as it has completed. The reduce method is called only after all intermediate data has been copied and sorted.

（B）Reducers start copying intermediate key-value pairs from each Mapper as soon as it has completed. The programmer can configure in the job what percentage of the intermediate data should arrive before the reduce method begins.

（C）Reducers start copying intermediate key-value pairs from each Mapper as soon as it has completed. The reduce method is called as soon as the intermediate key-value pairs start to arrive.

（D）Reduce methods and map methods all start at the beginning of a job, in order to provide optimal performance for map-only or reduce-only jobs.

（A）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.

（B）It returns a reference to a different Writable object time.

（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 from an object pool.

（E）It returns a reference to a Writable object. The API leaves unspecified whether this is a reused object or a new object.

（A）The ApplicationMaster requests resources from the ResourceManager

（B）The ResourceManager monitors and restarts any failed Containers of the ApplicationMaster

（C）The ApplicationMaster starts an instance of the ResourceManager within each Container

（D）The ApplicationMaster starts a single instance of the ResourceManager

（A）They would see the current of the file through the last completed block.

（B）They would see no content until the whole file written and closed.

（C）They would see Hadoop throw an ConcurrentFileAccessException when they try to access this file.

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

（A）Flume

（B）Oozie

（C）Pig

（D）Hive

（E）fuse-dfs

（F）Hue

（G）Sqoop

（A）Flume

（B）Oozie

（C）Pig

（D）Hive

（E）Hue

（F）HBase

（G）Sqoop

（A）Each MapReduce task will terminate after executing for 0.2 minutes

（B）The reducers will only output the first 20% of the data passed from the mappers

（C）A random sample of approximately 20% of the data will be output

（D）The SAMPLE command generates an "unexpected symbol" error

（A）The statement is not a valid Hive command

（B）A new table named mytable is created, and the contents of myothertable are copied into mytable

（C）Any existing data in mytable will be overwritten

（D）The contents of myothertable are appended to mytable

（A）Input file splits may cross line breaks. A line that crosses file splits is read by the RecordReader of the split that contains the beginning of the broken line.

（B）Input file splits may cross line breaks. A line that crosses file splits is read by the RecordReaders of both splits containing the broken line.

（C）The input file is split exactly at the line breaks, so each RecordReader will read a series of complete lines.

（D）Input file splits may cross line breaks. A line that crosses file splits is ignored.

（E）Input file splits may cross line breaks. A line that crosses file splits is read by the RecordReader of the split that contains the end of the broken line.

（A）Large-scale graph algorithms that require one-step link traversal.

（B）Algorithms that require applying the same mathematical function to large numbers of
individual binary records.

（C）Text analysis algorithms on large collections of unstructured text (e.g, Web crawls).

（D）Algorithms that require global, sharing states.

（E）Relational operations on large amounts of structured and semi-structured data.