article-followers: fast migration to move followers from settings to table

Rodrigo Souto · Rodrigo Souto
1 parent 45c0df82
Showing 1 changed file with 12 additions and 0 deletions Show diff stats
db/migrate/20151105175041_create_article_followers.rb
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+class CreateArticleFollowers < ActiveRecord::Migration
+  def self.up
+    execute("CREATE TABLE article_followers AS (SELECT profiles.id AS person_id, t.id AS article_id, clock_timestamp() AS since FROM (SELECT articles.id, regexp_split_to_table(replace(replace(substring(articles.setting FROM ':followers:[^:]*'), ':followers:', ''), '- ', ''), '\n') AS follower FROM articles) t INNER JOIN users ON users.email = follower INNER JOIN profiles ON users.id = profiles.user_id WHERE follower != '');")
+    add_index :article_followers, :person_id
+    add_index :article_followers, :article_id
+    add_index :article_followers, [:person_id, :article_id], :unique => true
+  end
+
+  def self.down
+    drop_table :article_followers
+  end
+end
...	...	@@ -0,0 +1,12 @@
	1	+class CreateArticleFollowers < ActiveRecord::Migration
	2	+ def self.up
	3	+ execute("CREATE TABLE article_followers AS (SELECT profiles.id AS person_id, t.id AS article_id, clock_timestamp() AS since FROM (SELECT articles.id, regexp_split_to_table(replace(replace(substring(articles.setting FROM ':followers:[^:]*'), ':followers:', ''), '- ', ''), '\n') AS follower FROM articles) t INNER JOIN users ON users.email = follower INNER JOIN profiles ON users.id = profiles.user_id WHERE follower != '');")
	4	+ add_index :article_followers, :person_id
	5	+ add_index :article_followers, :article_id
	6	+ add_index :article_followers, [:person_id, :article_id], :unique => true
	7	+ end
	8	+
	9	+ def self.down
	10	+ drop_table :article_followers
	11	+ end
	12	+end
...	...