#90

backend/spec/requests/posts_spec.rb

@@ -57,6 +57,23 @@ RSpec.describe 'Posts API', type: :request do
     post_write_params({ base_version_no: base_version.version_no }.merge(params))
   end
 
+  def count_sql_queries
+    count = 0
+
+    callback = lambda do |_name, _started, _finished, _id, payload|
+      next if payload[:cached]
+      next if ['SCHEMA', 'TRANSACTION'].include?(payload[:name])
+
+      count += 1
+    end
+
+    ActiveSupport::Notifications.subscribed(callback, 'sql.active_record') do
+      yield
+    end
+
+    count
+  end
+
   let!(:tag_name) { TagName.create!(name: 'spec_tag') }
   let!(:tag)      { Tag.create!(tag_name: tag_name, category: :general) }
 
@@ -558,6 +575,59 @@ RSpec.describe 'Posts API', type: :request do
           expect(sibling_ids).to include(sibling_post.id)
         end
       end
+
+      it 'does not issue a query per tag or related post' do
+        user = create_member_user!
+
+        tags =
+            15.times.map do |i|
+              tag_name = TagName.create!(name: "show_query_tag_#{ i }")
+              tag = Tag.create!(tag_name:, category: :general)
+              TagName.create!(name: "show_query_alias_#{ i }", canonical: tag_name)
+              PostTag.create!(post: post_record, tag:)
+              tag
+            end
+
+        tags.each_cons(2) do |parent_tag, child_tag|
+          TagImplication.create!(parent_tag:, tag: child_tag)
+        end
+
+        parent_post = Post.create!(
+          title: 'query parent post',
+          url: 'https://example.com/query-parent-post'
+        )
+        sibling_post = Post.create!(
+          title: 'query sibling post',
+          url: 'https://example.com/query-sibling-post'
+        )
+        child_post = Post.create!(
+          title: 'query child post',
+          url: 'https://example.com/query-child-post'
+        )
+
+        PostImplication.create!(post: post_record, parent_post:)
+        PostImplication.create!(post: sibling_post, parent_post:)
+        PostImplication.create!(post: child_post, parent_post: post_record)
+
+        20.times do |i|
+          related_post = Post.create!(
+            title: "query related post #{ i }",
+            url: "https://example.com/query-related-post-#{ i }"
+          )
+          PostSimilarity.create!(post: post_record,
+                                 target_post: related_post,
+                                 cos: 1.0 - (i / 100.0))
+        end
+
+        query_count =
+            count_sql_queries do
+              get "/posts/#{ post_record.id }",
+                  headers: { 'X-Transfer-Code' => user.inheritance_code }
+            end
+
+        expect(response).to have_http_status(:ok)
+        expect(query_count).to be <= 45
+      end
     end
 
     context 'when post does not exist' do