Reschedule another instance of RemoveRestrictedTodos migration

db/post_migrate/20181107054254_remove_restricted_todos_again.rb

+# frozen_string_literal: true
+
+# rescheduling of the revised RemoveRestrictedTodosWithCte background migration
+class RemoveRestrictedTodosAgain < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  disable_ddl_transaction!
+
+  MIGRATION = 'RemoveRestrictedTodos'.freeze
+  BATCH_SIZE = 1000
+  DELAY_INTERVAL = 5.minutes.to_i
+
+  class Project < ActiveRecord::Base
+    include EachBatch
+
+    self.table_name = 'projects'
+  end
+
+  def up
+    Project.where('EXISTS (SELECT 1 FROM todos WHERE todos.project_id = projects.id)')
+      .each_batch(of: BATCH_SIZE) do |batch, index|
+      range = batch.pluck('MIN(id)', 'MAX(id)').first
+
+      BackgroundMigrationWorker.perform_in(index * DELAY_INTERVAL, MIGRATION, range)
+    end
+  end
+
+  def down
+    # nothing to do
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20181101144347) do
+ActiveRecord::Schema.define(version: 20181107054254) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"