Can you use MapReduce to perform a relational join on two large tables sharing a key? Assume that the two tables are formatted as comma-separated files in HDFS.

The correct answer is A. Reduce-side join. Join Algorithms in MapReduce / Striped Striped variant variant / Memcached variant Which join to use? / In-memory join > map-side join > reduce-side join / Limitations of each? In-memory join: memory Map-side join: sort order and partitioning Reduce-side join: general purpose

Developing with Apache Spark Core

Question

Options

AReduce-side join
BMap-side join
CIn-memory join
DNo, MapReduce cannot perform relational operations.
ENo, but it can be done with either Pig or Hive.

How the community answered

(19 responses)

A
84% (16)
C
5% (1)
D
11% (2)

Explanation

Join Algorithms in MapReduce / Striped Striped variant variant / Memcached variant * Which join to use? / In-memory join > map-side join > reduce-side join / Limitations of each? In-memory join: memory Map-side join: sort order and partitioning Reduce-side join: general purpose

Topics

#reduce-side join#relational join#MapReduce#large tables

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