Use a CTE to remove the query timeout

2 files changed, 33 insertions, 1 deletions

diff --git a/db/migrate/20181002172433_remove_restricted_todos_with_cte.rb b/db/migrate/20181002172433_remove_restricted_todos_with_cte.rb
new file mode 100644
index 00000000000..0a8f4a12266
--- /dev/null
+++ b/db/migrate/20181002172433_remove_restricted_todos_with_cte.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+# rescheduling of the revised RemoveRestrictedTodos background migration
+class RemoveRestrictedTodosWithCte < ActiveRecord::Migration
+  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
diff --git a/db/schema.rb b/db/schema.rb
index 773bfb96b93..4ff0272428a 100644
--- a/db/schema.rb
+++ b/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: 20180924201039) do
+ActiveRecord::Schema.define(version: 20181002172433) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"