[bug#3919] (Re)-implemented execute handler method.

        return errs.get_dict()

    @listed

    def execute(self, conn, query, command):

        '''

        Execute command on matched objects (must be roles hv or host).

        :param query: the tql query to select objects.

        :param command: the command to execute on each object

        :return: a dict where key is the id of a selected object, and the value

            a tuple (errcode, message) where errcode is (success|error|warn) and

            message an error message or the output of the command in case of

            success.

        '''

        self._check(conn, 'execute', query)

        objects = self._server.list(query, show=set(('r',)))

        errs = Reporter()

        for obj in objects:

            if obj['r'] not in ('hv', 'host'):

                errs.error(obj['id'], 'bad role')

                continue

            try:

                objcon = self._server.get_connection(obj['id'])

            except KeyError:

                errs.error(obj['id'], 'node not connected')

            else:

                returned = objcon.connection.call('execute_command', command)

                errs.success(obj['id'], returned)

        return errs.get_dict()

    @listed

    def dbstats(self, conn):

        '''