Using embeds on a child association to improve performance of sorting?

问题

I have a contact and a lead. They are completely two independent models. I have a leads page where I can query against leads, sort by leads and do other work on leads. Also, a contact can be created without a lead. However, a contact can has_one lead. So I set up my models like so:

class Contact
  include Mongoid::Document
  has_one :lead

  field :reference_number
  field :some_date
end

class Lead
  include Mongoid::Document
  belongs_to :contact

  field :status
end

Here is the problem. On the leads page, I want to sort leads by the reference_number which is an attribute of the contact. Because Contact and Lead are independent models, I cannot embed a lead into a contact, because I need to query leads on their own. So embed_one is NOT a solution. The other option I first tried was sorting using ruby, but with 10,000+ documents, this was extremely slow and quickly faded as a solution:

Lead.order_by( id: all.sort_by { |lead| lead.contact.reference_number }.map(&:id) )

So the only remaining solution is using some type of cache. First, I tried using a hash field like this:

class Lead
  ...
  field :denormalized_fields, type: Hash, default: {}

But this is not good either, because I still cannot sort by key/value pairs in a hash. This would not work:

Lead.order_by(denormalized_fields['reference_number'] => 'asc')

So I only have one remaining idea, but I am not sure if this is a good solution either. I introduce a new document called ParentAttribute:

class ParentAttribute
  include Mongoid::Document

  field :reference_number
end

class Contact
  include Mongoid::Document
  has_one :parent_attribute
  has_one :lead
end

class Lead
  include Mongoid::Document
  belongs_to :contact
  embeds_one :parent_attribute
end

Now when I create a contact, rather than storing fields in Contact, I store it in ParentAttribute. And a Contact will still has_one lead, but I can also query against the attributes in Lead:

Lead.order_by(:'parent_attributes.reference_number' => 'asc')

I have no other ideas. Can I get some insights into my issue here?

来源：https://stackoverflow.com/questions/52358962/using-embeds-on-a-child-association-to-improve-performance-of-sorting

标签

ruby-on-rails

mongodb

mongoid