Gather issuable metadata to avoid n+ queries on index viewissue_25900_2

3 files changed, 19 insertions, 0 deletions

diff --git a/app/models/award_emoji.rb b/app/models/award_emoji.rb
index 46b17479d6d..6937ad3bdd9 100644
--- a/app/models/award_emoji.rb
+++ b/app/models/award_emoji.rb
@@ -16,6 +16,14 @@ class AwardEmoji < ActiveRecord::Base
   scope :downvotes, -> { where(name: DOWNVOTE_NAME) }
   scope :upvotes,   -> { where(name: UPVOTE_NAME) }
 
+  class << self
+    def votes_for_collection(ids, type)
+      select('name', 'awardable_id', 'COUNT(*) as count').
+        where('name IN (?) AND awardable_type = ? AND awardable_id IN (?)', [DOWNVOTE_NAME, UPVOTE_NAME], type, ids).
+        group('name', 'awardable_id')
+    end
+  end
+
   def downvote?
     self.name == DOWNVOTE_NAME
   end
diff --git a/app/models/concerns/issuable.rb b/app/models/concerns/issuable.rb
index 3517969eabc..bfb54e878fc 100644
--- a/app/models/concerns/issuable.rb
+++ b/app/models/concerns/issuable.rb
@@ -15,6 +15,11 @@ module Issuable
   include Taskable
   include TimeTrackable
 
+  # This object is used to gather issuable meta data for displaying
+  # upvotes, downvotes and notes count for issues and merge requests
+  # lists avoiding n+1 queries and improving performance.
+  IssuableMeta = Struct.new(:upvotes, :downvotes, :notes_count)
+
   included do
     cache_markdown_field :title, pipeline: :single_line
     cache_markdown_field :description
diff --git a/app/models/note.rb b/app/models/note.rb
index bf090a0438c..029fe667a45 100644
--- a/app/models/note.rb
+++ b/app/models/note.rb
@@ -108,6 +108,12 @@ class Note < ActiveRecord::Base
       Discussion.for_diff_notes(active_notes).
         map { |d| [d.line_code, d] }.to_h
     end
+
+    def count_for_collection(ids, type)
+      user.select('noteable_id', 'COUNT(*) as count').
+        group(:noteable_id).
+        where(noteable_type: type, noteable_id: ids)
+    end
   end
 
   def cross_reference?