versions

# File activerecord/lib/active_record/schema_migration.rb, line 76
    def versions
      sm = Arel::SelectManager.new(arel_table)
      sm.project(arel_table[primary_key])
      sm.order(arel_table[primary_key].asc)

      @pool.with_connection do |connection|
        connection.select_values(sm, "#{self.class} Load")
      end
    end