Milestoneish SQL performance partially improved and memoized

Memoize Milestoneish#issues_visible_to_user and counts to reduce lookups
Milstoneish SQL optimised with project, but still slow on GlobalMilestone

app/models/concerns/milestoneish.rb

 module Milestoneish
   def closed_items_count(user)
-    issues_visible_to_user(user).closed.size + merge_requests.closed_and_merged.size
+    memoize_per_user(user, :closed_items_count) do
+      (count_issues_by_state(user)['closed'] || 0) + merge_requests.closed_and_merged.size
+    end
   end
 
   def total_items_count(user)
-    issues_visible_to_user(user).size + merge_requests.size
+    memoize_per_user(user, :total_items_count) do
+      issues_count = count_issues_by_state(user).values.sum
+      issues_count + merge_requests.size
+    end
   end
 
   def complete?(user)
@@ -30,7 +35,10 @@ module Milestoneish
   end
 
   def issues_visible_to_user(user)
-    IssuesFinder.new(user).execute.where(id: issues)
+    memoize_per_user(user, :issues_visible_to_user) do
+      params = try(:project_id) ? { project_id: project_id } : {}
+      IssuesFinder.new(user, params).execute.where(milestone_id: milestoneish_ids)
+    end
   end
 
   def upcoming?
@@ -50,4 +58,18 @@ module Milestoneish
   def expired?
     due_date && due_date.past?
   end
+
+  private
+
+  def count_issues_by_state(user)
+    memoize_per_user(user, :count_issues_by_state) do
+      issues_visible_to_user(user).reorder(nil).group(:state).count
+    end
+  end
+
+  def memoize_per_user(user, method_name)
+    @memoized ||= {}
+    @memoized[method_name] ||= {}
+    @memoized[method_name][user.try!(:id)] ||= yield
+  end
 end

app/models/global_milestone.rb

@@ -24,12 +24,16 @@ class GlobalMilestone
     @first_milestone = milestones.find {|m| m.description.present? } || milestones.first
   end
 
+  def milestoneish_ids
+    milestones.select(:id)
+  end
+
   def safe_title
     @title.to_slug.normalize.to_s
   end
 
   def projects
-    @projects ||= Project.for_milestones(milestones.select(:id))
+    @projects ||= Project.for_milestones(milestoneish_ids)
   end
 
   def state
@@ -49,11 +53,11 @@ class GlobalMilestone
   end
 
   def issues
-    @issues ||= Issue.of_milestones(milestones.select(:id)).includes(:project, :assignee, :labels)
+    @issues ||= Issue.of_milestones(milestoneish_ids).includes(:project, :assignee, :labels)
   end
 
   def merge_requests
-    @merge_requests ||= MergeRequest.of_milestones(milestones.select(:id)).includes(:target_project, :assignee, :labels)
+    @merge_requests ||= MergeRequest.of_milestones(milestoneish_ids).includes(:target_project, :assignee, :labels)
   end
 
   def participants

app/models/milestone.rb

@@ -129,6 +129,10 @@ class Milestone < ActiveRecord::Base
     self.title
   end
 
+  def milestoneish_ids
+    id
+  end
+
   def can_be_closed?
     active? && issues.opened.count.zero?
   end

changelogs/unreleased/jej-memoize-milestoneish-visible-to-user.yml

+---
+title: Milestoneish SQL performance partially improved and memoized
+merge_request: 8146
+author: