From 5f94c29adab94c1f101b3961f5c52637d5c98ed5 Mon Sep 17 00:00:00 2001
From: Neil Lalonde <neillalonde@gmail.com>
Date: Tue, 17 Jun 2014 17:01:13 -0400
Subject: [PATCH] Add index on topic_links post_id. Remove a redundant index.

---
 ...7193351_add_and_remove_indexes_on_topic_links.rb | 13 +++++++++++++
 1 file changed, 13 insertions(+)
 create mode 100644 db/migrate/20140617193351_add_and_remove_indexes_on_topic_links.rb

diff --git a/db/migrate/20140617193351_add_and_remove_indexes_on_topic_links.rb b/db/migrate/20140617193351_add_and_remove_indexes_on_topic_links.rb
new file mode 100644
index 000000000..1ddbf6e8f
--- /dev/null
+++ b/db/migrate/20140617193351_add_and_remove_indexes_on_topic_links.rb
@@ -0,0 +1,13 @@
+class AddAndRemoveIndexesOnTopicLinks < ActiveRecord::Migration
+  def up
+    # Index (topic_id) is a subset of (topic_id, post_id, url)
+    remove_index :topic_links, :topic_id
+
+    add_index :topic_links, :post_id
+  end
+
+  def down
+    remove_index :topic_links, :post_id
+    add_index :topic_links, :topic_id
+  end
+end