Merge branch 'dm-discussions-n-plus-1' into 'master'

Resolve N+1 query issue with discussions

Closes #33013

See merge request !11775

3 files changed, 9 insertions, 3 deletions

diff --git a/app/models/concerns/noteable.rb b/app/models/concerns/noteable.rb
index dd1e6630642..c7bdc997eca 100644
--- a/app/models/concerns/noteable.rb
+++ b/app/models/concerns/noteable.rb
@@ -43,7 +43,12 @@ module Noteable
   end
 
   def resolvable_discussions
-    @resolvable_discussions ||= discussion_notes.resolvable.discussions(self)
+    @resolvable_discussions ||=
+      if defined?(@discussions)
+        @discussions.select(&:resolvable?)
+      else
+        discussion_notes.resolvable.discussions(self)
+      end
   end
 
   def discussions_resolvable?
diff --git a/app/models/discussion.rb b/app/models/discussion.rb
index 0b6b920ed66..9b32d573387 100644
--- a/app/models/discussion.rb
+++ b/app/models/discussion.rb
@@ -21,7 +21,8 @@ class Discussion
   end
 
   def self.build_collection(notes, context_noteable = nil)
-    notes.group_by { |n| n.discussion_id(context_noteable) }.values.map { |notes| build(notes, context_noteable) }
+    grouped_notes = notes.group_by { |n| n.discussion_id(context_noteable) }
+    grouped_notes.values.map { |notes| build(notes, context_noteable) }
   end
 
   # Returns an alphanumeric discussion ID based on `build_discussion_id`
diff --git a/app/models/note.rb b/app/models/note.rb
index 60257aac93b..832c68243fb 100644
--- a/app/models/note.rb
+++ b/app/models/note.rb
@@ -110,7 +110,7 @@ class Note < ActiveRecord::Base
     end
 
     def discussions(context_noteable = nil)
-      Discussion.build_collection(fresh, context_noteable)
+      Discussion.build_collection(all.includes(:noteable).fresh, context_noteable)
     end
 
     def find_discussion(discussion_id)