Hortonworks Exam HDPCD Topic 2 Question 52 Discussion

Actual exam question for Hortonworks's HDPCD exam

Question #: 52
Topic #: 2

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

AThe default partitioner assigns key-values pairs to reduces based on an internal random number generator.

BThe 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.

CThe 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.

DThe 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.

EThe 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.

Show Suggested Answer

Suggested Answer: D

The default partitioner computes a hash value for the key and assigns the partition based on this result.

The default Partitioner implementation is called HashPartitioner. It uses the hashCode() method of the key objects modulo the number of partitions total to determine which partition to send a given (key, value) pair to.

In Hadoop, the default partitioner is HashPartitioner, which hashes a record's key to determine which partition (and thus which reducer) the record belongs in.The number of partition is then equal to the number of reduce tasks for the job.

by Veronika at Mar 18, 2024, 03:58 PM

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8 months ago

I think the default partitioner assigns key-values pairs to reducers based on an internal random number generator.

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