Merge branch 'issue-18036' into 'master'

Cache assigned issue and merge request count. Closes #18036 and #18035

See merge request !4378

6 files changed, 62 insertions, 2 deletions

diff --git a/CHANGELOG b/CHANGELOG
index 2467a45c0eb..dedaf9090a2 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -27,6 +27,7 @@ v 8.9.0 (unreleased)
   - Measure queue duration between gitlab-workhorse and Rails
   - Make authentication service for Container Registry to be compatible with < Docker 1.11
   - Add Application Setting to configure Container Registry token expire delay (default 5min)
+  - Cache assigned issue and merge request counts in sidebar nav
 
 v 8.8.3
   - Fix incorrect links on pipeline page when merge request created from fork
diff --git a/app/models/concerns/issuable.rb b/app/models/concerns/issuable.rb
index 2326a395cb8..50f5b749e38 100644
--- a/app/models/concerns/issuable.rb
+++ b/app/models/concerns/issuable.rb
@@ -68,6 +68,14 @@ module Issuable
     strip_attributes :title
 
     acts_as_paranoid
+
+    after_save :update_assignee_cache_counts, if: :assignee_id_changed?
+
+    def update_assignee_cache_counts
+      # make sure we flush the cache for both the old *and* new assignee
+      User.find(assignee_id_was).update_cache_counts if assignee_id_was
+      assignee.update_cache_counts if assignee
+    end
   end
 
   module ClassMethods
diff --git a/app/models/user.rb b/app/models/user.rb
index 15b6cbc2255..172845c9d25 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -776,6 +776,23 @@ class User < ActiveRecord::Base
     notification_settings.find_or_initialize_by(source: source)
   end
 
+  def assigned_open_merge_request_count(force: false)
+    Rails.cache.fetch(['users', id, 'assigned_open_merge_request_count'], force: force) do
+      assigned_merge_requests.opened.count
+    end
+  end
+
+  def assigned_open_issues_count(force: false)
+    Rails.cache.fetch(['users', id, 'assigned_open_issues_count'], force: force) do
+      assigned_issues.opened.count
+    end
+  end
+
+  def update_cache_counts
+    assigned_open_merge_request_count(force: true)
+    assigned_open_issues_count(force: true)
+  end
+
   private
 
   def projects_union
diff --git a/app/views/layouts/nav/_dashboard.html.haml b/app/views/layouts/nav/_dashboard.html.haml
index 43532b0c155..306ebd5fcf7 100644
--- a/app/views/layouts/nav/_dashboard.html.haml
+++ b/app/views/layouts/nav/_dashboard.html.haml
@@ -30,13 +30,13 @@
       = icon('exclamation-circle fw')
       %span
         Issues
-        %span.count= number_with_delimiter(current_user.assigned_issues.opened.count)
+        %span.count= number_with_delimiter(current_user.assigned_open_issues_count)
   = nav_link(path: 'dashboard#merge_requests') do
     = link_to assigned_mrs_dashboard_path, title: 'Merge Requests', class: 'dashboard-shortcuts-merge_requests' do
       = icon('tasks fw')
       %span
         Merge Requests
-        %span.count= number_with_delimiter(current_user.assigned_merge_requests.opened.count)
+        %span.count= number_with_delimiter(current_user.assigned_open_merge_request_count)
   = nav_link(controller: :snippets) do
     = link_to dashboard_snippets_path, title: 'Snippets' do
       = icon('clipboard fw')
diff --git a/spec/models/issue_spec.rb b/spec/models/issue_spec.rb
index 87b3d8d650a..b87d68283e6 100644
--- a/spec/models/issue_spec.rb
+++ b/spec/models/issue_spec.rb
@@ -269,4 +269,21 @@ describe Issue, models: true do
       end
     end
   end
+
+  describe 'cached counts' do
+    it 'updates when assignees change' do
+      user1 = create(:user)
+      user2 = create(:user)
+      issue = create(:issue, assignee: user1)
+
+      expect(user1.assigned_open_issues_count).to eq(1)
+      expect(user2.assigned_open_issues_count).to eq(0)
+
+      issue.assignee = user2
+      issue.save
+
+      expect(user1.assigned_open_issues_count).to eq(0)
+      expect(user2.assigned_open_issues_count).to eq(1)
+    end
+  end
 end
diff --git a/spec/models/merge_request_spec.rb b/spec/models/merge_request_spec.rb
index 118e1e22a78..a4c55cc2fd0 100644
--- a/spec/models/merge_request_spec.rb
+++ b/spec/models/merge_request_spec.rb
@@ -438,4 +438,21 @@ describe MergeRequest, models: true do
       expect(mr.participants).to include(note1.author, note2.author)
     end
   end
+
+  describe 'cached counts' do
+    it 'updates when assignees change' do
+      user1 = create(:user)
+      user2 = create(:user)
+      mr = create(:merge_request, assignee: user1)
+
+      expect(user1.assigned_open_merge_request_count).to eq(1)
+      expect(user2.assigned_open_merge_request_count).to eq(0)
+
+      mr.assignee = user2
+      mr.save
+
+      expect(user1.assigned_open_merge_request_count).to eq(0)
+      expect(user2.assigned_open_merge_request_count).to eq(1)
+    end
+  end
 end