Random record from MongoDB

Question

I am looking to get a random record from a huge (100 million record) mongodb.

What is the fastest and most efficient way to do so? The data is already t

Answer 1

If you're using mongoid, the document-to-object wrapper, you can do the following in Ruby. (Assuming your model is User)

User.all.to_a[rand(User.count)]

In my .irbrc, I have

def rando klass
    klass.all.to_a[rand(klass.count)]
end

so in rails console, I can do, for example,

rando User
rando Article

to get documents randomly from any collection.