gitlab-org--gitlab-foss/db/post_migrate/20181107054254_remove_restricted_todos_again.rb

# frozen_string_literal: true

# rescheduling of the revised RemoveRestrictedTodosWithCte background migration
class RemoveRestrictedTodosAgain < ActiveRecord::Migration[4.2]
  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