activerecord - MongoDB vs MySQL

Question

I used to build Ruby on Rails apps with MySQL.

MongoDB currently become more and more famous and I am now starting to give it a try.

The problem is, I don't know the underlying theory of how MongoDB is working (am using mongoid gem if it matter)

So I would like to have a comparison on the performance between using MySQL+ActiveRecord and model generated by mongoid gem, could anyone help me to figure it out?

Answer 1

The article entitled: What the heck are you actually using NoSQL for? does a very good job at presenting the pros and cons of using NoSQL.

Edit: Also read http://blog.fatalmind.com/2011/05/13/choosing-nosql-for-the-right-reason/ blog post too

Re-edit: I found some recent material (published in 2014) on this topic that I consider to be relevant: What’s left of NoSQL?