Mongoid identity map and fibers

gistfile1.rb

# See: https://github.com/mongoid/mongoid/blob/identity-map/spec/unit/mongoid/identity_map_spec.rb#L367

# In order for the identity map to work when using fibers the 
# entire unit of work must happen on the same fiber since it's using
# thread locals for storage.

# The following example is correct:
fiber = Fiber.new do
  Person.find(id)
  Person.find(id) # This query hits the identity map.
end
fiber.resume

# The following example is incorrect:
Person.find(id)
fiber = Fiber.new do
  Person.find(id) # This query hits the database.
end
fiber.resume