fixed n+1 query jobs#index

app/controllers/jobs_controller.rb

@@ -3,7 +3,7 @@ class JobsController < ApplicationController
     if job_params.present?
       search
     else
-      @jobs = Job.includes(:company, :cities_jobs, :cities).page(params[:page]).per(Job::JOB_PER_PAGE)
+      @jobs = Job.sort_by_date.page(params[:page]).per(Job::JOB_PER_PAGE)
     end
   end
 
@@ -17,7 +17,7 @@ class JobsController < ApplicationController
     if job_params.key?(:model) && job_params.key?(:slug) # search by model
       model = params[:model].classify.constantize
       @target = model.find_by(slug: job_params[:slug])
-      @jobs = @target.jobs.includes(:company, :cities_jobs, :cities).page(params[:page]).per(Job::JOB_PER_PAGE)
+      @jobs = @target.jobs.sort_by_date.page(params[:page]).per(Job::JOB_PER_PAGE)
     end
   end
 

app/controllers/top_controller.rb

 class TopController < ApplicationController
   def index
     @total_job = Job.count
-    @latest_jobs = Job.latest
+    @latest_jobs = Job.sort_by_date.limit(Job::LATEST_JOBS_LIMIT)
     @top_cities = City.top_jobs
     @top_industries = Industry.top_jobs
   end

app/models/job.rb

@@ -9,7 +9,7 @@ class Job < ApplicationRecord
   has_many :favorite_jobs, dependent: :destroy
   has_many :history_job, dependent: :destroy
 
-  def self.latest
-    joins(:cities).includes(:cities, :cities_jobs, :company).order(created_at: :desc).limit(LATEST_JOBS_LIMIT)
+  def self.sort_by_date
+    joins(:cities).includes(:cities, :cities_jobs, :company).order(created_at: :desc)
   end
 end

app/views/jobs/index.html.slim

@@ -21,8 +21,7 @@
         p.job-salary.text-success
           | Salary: #{job.salary}
         ul.list-unstyled
-          - city_list = job.cities
-          = show_location(city_list)
+          = show_location(job.cities)
         .job-desc
           = truncate(simple_format(job.description), escape: false, length: 250)
       hr.my-4