perf: batch preload hashtags/tags/category/user names in get_videos to avoid N+1 queries

app/controllers/video_pros_controller.rb

@@ -240,18 +240,33 @@ class VideoProsController < ApplicationController
   end
 
   private
-  def get_videos(video_images, show_url, custom_data_field={})
-    @autoplay_video = custom_data_field[:autoplay_video] rescue "0"
-    @hide_video_tools = custom_data_field[:hide_video_tools] == "1" rescue false
-    videos = []
-    video_images.each_with_index do |video_image,i|
+   def get_videos(video_images, show_url, custom_data_field={})
+     @autoplay_video = custom_data_field[:autoplay_video] rescue "0"
+     @hide_video_tools = custom_data_field[:hide_video_tools] == "1" rescue false
+
+     video_image_ids = video_images.map(&:id)
+     hashtaggings_by_video = Hashtagging.where(:hashtaggable_id.in => video_image_ids, :hashtaggable_type => "VideoImage").group_by(&:hashtaggable_id)
+     all_hashtag_ids = hashtaggings_by_video.values.flatten.map(&:hashtag_id).compact.uniq
+     hashtags_by_id = Hashtag.where(:id.in => all_hashtag_ids).to_a.index_by(&:id)
+
+     taggings_by_video = Tagging.where(:taggable_id.in => video_image_ids, :taggable_type => "VideoImage").group_by(&:taggable_id)
+     all_tag_ids = taggings_by_video.values.flatten.map(&:tag_id).compact.uniq
+     tags_by_id = Tag.where(:id.in => all_tag_ids).to_a.index_by(&:id)
+
+     all_category_ids = video_images.map(&:category_id).compact.uniq
+     categories_by_id = Category.where(:id.in => all_category_ids).to_a.index_by(&:id)
+
+     id_name_mapping = User.where(:id.in=>video_images.map(&:update_user_id).compact.uniq).pluck(:id, "member_name.#{I18n.locale}").map{|k,v| [k.to_s, (v ? v.values.last : nil)]}.to_h
+
+     videos = []
+     video_images.each_with_index do |video_image,i|
        if video_image.language_enabled.include?(I18n.locale.to_s)
         snapshot_url = video_image.get_snapshot_url
         next if snapshot_url.nil?
-        video_post_agency = video_image.post_agency(@video_pro_setting)
+        video_post_agency = video_image.post_agency(@video_pro_setting, id_name_mapping)
         video_postdate = video_image.postdate.to_s
-        video_category = video_image.category_title
-        video_tags = video_image.tags
+        video_category = video_image.category_title(categories_by_id[video_image.category_id])
+        video_tags = video_image.tags((taggings_by_video[video_image.id] || []).map{|tg| tags_by_id[tg.tag_id]}.compact)     
         video_tags = (video_tags.count > 0 ? video_tags.collect{|tag| {"video_tag" => tag.name}} : [{"video_tag" => video_category}])
         statuses = video_image.statuses_with_classname
         video_desc = video_image.desc

app/models/video_image.rb

@@ -89,9 +89,11 @@ class VideoImage
   def inc_count
     self.class.where(:id=>self.id).update_all({"$inc"=>{"view_count"=>1}})
   end
-  def category_title
-    self.category.title rescue ""
+  
+  def category_title(preloaded_category=nil)
+    self.category(preloaded_category).title rescue ""
   end
+  
   def post_agencies_translations
     if defined?(OrbitHelper::SharedHash) && OrbitHelper::SharedHash
       OrbitHelper::SharedHash['video_pro'][:post_agencies_translations] rescue VideoProSetting.first.post_agencies_translations
@@ -102,7 +104,8 @@ class VideoImage
   def get_override_post_agency
     self.post_agencies_translations[I18n.locale.to_s][self.override_post_agency] rescue ""
   end
-  def post_agency(video_pro_setting=nil)
+  
+  def post_agency(video_pro_setting=nil, id_name_mapping=nil)
     if self.use_override_post_agency
       self.get_override_post_agency
     else
@@ -112,16 +115,17 @@ class VideoImage
       if video_pro_setting && video_pro_setting.enable_name_mapping
         tmp = video_pro_setting.user_mapping[self.update_user_id] rescue nil
         if tmp.blank?
-          user_name = User.where(:id=>self.update_user_id).pluck(:member_name).first[I18n.locale.to_s] rescue nil
+          user_name = id_name_mapping ? id_name_mapping[self.update_user_id] : (User.where(:id=>self.update_user_id).pluck(:member_name).first[I18n.locale.to_s] rescue nil)
         else
           user_name = tmp
         end
       else
-        user_name = User.where(:id=>self.update_user_id).pluck(:member_name).first[I18n.locale.to_s] rescue nil
+        user_name = id_name_mapping ? id_name_mapping[self.update_user_id] : (User.where(:id=>self.update_user_id).pluck(:member_name).first[I18n.locale.to_s] rescue nil)
       end
       user_name
     end
   end
+
   def generate_video_snapshot
     if self.video_file?
       self.default_video_snapshot = true