class MigrateIssuesToGhostUser < ActiveRecord::Migration[4.2] include Gitlab::Database::MigrationHelpers DOWNTIME = false disable_ddl_transaction! class User < ActiveRecord::Base self.table_name = 'users' end class Issue < ActiveRecord::Base self.table_name = 'issues' include ::EachBatch end def reset_column_in_migration_models ActiveRecord::Base.clear_cache! ::User.reset_column_information ::Namespace.reset_column_information end def up reset_column_in_migration_models # we use the model method because rewriting it is too complicated and would require copying multiple methods ghost_id = ::User.ghost.id Issue.where('NOT EXISTS (?)', User.unscoped.select(1).where('issues.author_id = users.id')).each_batch do |relation| relation.update_all(author_id: ghost_id) end end def down end end