From c1972f8438dbe37a1c377f9b367c68573e562496 Mon Sep 17 00:00:00 2001
From: Guo Xiang Tan <tgx_world@hotmail.com>
Date: Thu, 21 Jun 2018 09:44:49 +0800
Subject: [PATCH] PERF: Add index_topic_id_percent_rank_on_posts.

Speeds up the `Posts#summary` mode query for large topics.
---
 ...621013807_add_index_topic_id_percent_rank_on_posts.rb | 9 +++++++++
 1 file changed, 9 insertions(+)
 create mode 100644 db/migrate/20180621013807_add_index_topic_id_percent_rank_on_posts.rb

diff --git a/db/migrate/20180621013807_add_index_topic_id_percent_rank_on_posts.rb b/db/migrate/20180621013807_add_index_topic_id_percent_rank_on_posts.rb
new file mode 100644
index 00000000000..d7a2f1f81d7
--- /dev/null
+++ b/db/migrate/20180621013807_add_index_topic_id_percent_rank_on_posts.rb
@@ -0,0 +1,9 @@
+class AddIndexTopicIdPercentRankOnPosts < ActiveRecord::Migration[5.2]
+  def up
+    add_index :posts, [:topic_id, :percent_rank], order: { percent_rank: :asc }
+  end
+
+  def down
+    remove_index :posts, [:topic_id, :percent_rank]
+  end
+end