What is distributed cache in Hadoop?

Question

Can anyone explain what is distributed cache in Hadoop?

Answer 1

Distributed cache is a service by Hadoop’s MapReduce framework to cache small to moderate read-only files when needed.

Once a file is cached for a specific job, Hadoop will broadcast them to each DataNode both in the system and in memory, where map and reduce tasks are executed.

When required, it helps to access and read the cache file easily and populate any collection (like an array, or hashmap) in your code.

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This is most frequently asked in interviews and you can check out this blog on Hadoop Interview Questions for other FAQs in an interview with simple and lucid explanations. 

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