lease

# File activerecord/lib/active_record/connection_adapters/abstract_adapter.rb, line 298
      def lease
        if in_use?
          msg = +"Cannot lease connection, "
          if @owner == ActiveSupport::IsolatedExecutionState.context
            msg << "it is already leased by the current thread."
          else
            msg << "it is already in use by a different thread: #{@owner}. "                     "Current thread: #{ActiveSupport::IsolatedExecutionState.context}."
          end
          raise ActiveRecordError, msg
        end

        @owner = ActiveSupport::IsolatedExecutionState.context
      end