Forking without resetting the Connection.

fork_fail.rb

require 'rubygems'
require 'mongo'

# A class to store our DB object
class Foo
  def self.db
    @@db ||= Mongo::Connection.new['stuff']
  end
end

# Now insert some data
10.times do |n|
  Foo.db['things'].save({:a => n})
end

# Now fork. You'll almost always see an exception here.
if !Kernel.fork
  puts "This is the child!"
  10.times do
    p "Child 0: #{Foo.db['things'].find_one}"
  end
else
  puts "This is the parent"
  10.times do
    p "Parent: #{Foo.db['things'].find_one}"
  end
end