Remove N+1 caused by question.publishable_results?

[sauloperez]

https://github.com/coopdevs/decidim-module-action_delegator/blob/1c22b438cbd51afcc7ac4cfb41bc70deacb94f5f/app/views/decidim/action_delegator/admin/consultations/results.html.erb#L40

Is causing a couple N+1. That's because for every question we call Decidim's Question#publishable_results? which in turn calls consultation.finished? and responses.order(votes_count: :desc).

This results in the following logs

Decidim::Consultation Load (0.7ms)  SELECT  "decidim_consultations".* FROM "decidim_consultations" WHERE "decidim_consultations"."id" = $1 LIMIT $2  [["id", 1], ["LIMIT", 1]]                
  ↳ /home/pau/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/bundler/gems/decidim-dd26de389f5a/decidim-consultations/app/models/decidim/consultations/question.rb:79                                 
  Decidim::Consultations::Response Exists (0.7ms)  SELECT  1 AS one FROM "decidim_consultations_responses" WHERE "decidim_consultations_responses"."decidim_consultations_questions_id" = $1 LIM
IT $2  [["decidim_consultations_questions_id", 5], ["LIMIT", 1]]                                                                                                                                
  ↳ /home/pau/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/bundler/gems/decidim-dd26de389f5a/decidim-consultations/app/models/decidim/consultations/question.rb:79                                 
  CACHE Decidim::Consultation Load (0.0ms)  SELECT  "decidim_consultations".* FROM "decidim_consultations" WHERE "decidim_consultations"."id" = $1 LIMIT $2  [["id", 1], ["LIMIT", 1]]          
  ↳ /home/pau/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/bundler/gems/decidim-dd26de389f5a/decidim-consultations/app/models/decidim/consultations/question.rb:79                                 
  Decidim::Consultations::Response Exists (1.4ms)  SELECT  1 AS one FROM "decidim_consultations_responses" WHERE "decidim_consultations_responses"."decidim_consultations_questions_id" = $1 LIM
IT $2  [["decidim_consultations_questions_id", 8], ["LIMIT", 1]]                                                                                                                                
  ↳ /home/pau/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/bundler/gems/decidim-dd26de389f5a/decidim-consultations/app/models/decidim/consultations/question.rb:79
  CACHE Decidim::Consultation Load (0.0ms)  SELECT  "decidim_consultations".* FROM "decidim_consultations" WHERE "decidim_consultations"."id" = $1 LIMIT $2  [["id", 1], ["LIMIT", 1]]
  ↳ /home/pau/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/bundler/gems/decidim-dd26de389f5a/decidim-consultations/app/models/decidim/consultations/question.rb:79
  Decidim::Consultations::Response Exists (0.8ms)  SELECT  1 AS one FROM "decidim_consultations_responses" WHERE "decidim_consultations_responses"."decidim_consultations_questions_id" = $1 LIM
IT $2  [["decidim_consultations_questions_id", 6], ["LIMIT", 1]]
  ↳ /home/pau/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/bundler/gems/decidim-dd26de389f5a/decidim-consultations/app/models/decidim/consultations/question.rb:79
  CACHE Decidim::Consultation Load (0.0ms)  SELECT  "decidim_consultations".* FROM "decidim_consultations" WHERE "decidim_consultations"."id" = $1 LIMIT $2  [["id", 1], ["LIMIT", 1]]
  ↳ /home/pau/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/bundler/gems/decidim-dd26de389f5a/decidim-consultations/app/models/decidim/consultations/question.rb:79
  Decidim::Consultations::Response Exists (0.8ms)  SELECT  1 AS one FROM "decidim_consultations_responses" WHERE "decidim_consultations_responses"."decidim_consultations_questions_id" = $1 LIM
IT $2  [["decidim_consultations_questions_id", 7], ["LIMIT", 1]]
  ↳ /home/pau/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/bundler/gems/decidim-dd26de389f5a/decidim-consultations/app/models/decidim/consultations/question.rb:79
  Rendered /home/pau/dev/decidim-module-action_delegator/app/views/decidim/action_delegator/admin/consultations/results.html.erb within layouts/decidim/admin/consultation (20.5ms)
  Rendered /home/pau/.rbenv/versions/2.7.3/lib/ruby/gems/2.7.0/bundler/gems/decidim-dd26de389f5a/decidim-core/app/views/layouts/decidim/_organization_colors.html.erb (0.3ms)
  Decidim::DecidimAwesome::AwesomeConfig Load (1.0ms)  SELECT "decidim_awesome_config".* FROM "decidim_awesome_config" WHERE "decidim_awesome_config"."decidim_organization_id" = $1  [["decidim
_organization_id", 1]]

Proposed solution

The solution is to eager load both the consultation and the responses as part of the query performed from https://github.com/coopdevs/decidim-module-action_delegator/pull/106/files#diff-3e9e68c68f5a828e175f3957f398f80a95e20967f772bfe6be7aba260c01db36R59-R70. At this point, that method should probably be renamed to #results_query. It reaches out to many more tables than just questions.