Is there an example implementation of MapReduce without using Hadoop?

Question

Java

Hello!
Is there an example implementation of MapReduce without using Hadoop?
If in the context of the task, then (example):
There are N database servers, with the same table structure and with a different data set.
I want to send a request to all N servers and get one response.
Thanks in advance!

Answer 1

The MapReduce paradigm is implemented, for example, in mongodb. You can play there. In general, the paradigm itself comes from functional languages, so look in their direction. If Java is closer, then I advise Clojure.
As for your task, I can’t suggest anything for classic relational databases, but something similar is now being developed in the direction of NewSQL databases.