overflow_test.rb

require 'mongo'

c = Mongo::Connection.new

c['test']['nums'].remove
c['test']['nums'].save({:n => 2147483635})

1000.times do
  c['test']['nums'].update({}, {"$inc" => {:n => 1}})
  p c['test']['nums'].find_one
  if c['test']['nums'].find_one({:n => {"$type" => 16}})
    p "Int"
  elsif c['test']['nums'].find_one({:n => {"$type" => 18}})
    p "long"
  end
end