FTWRL on a non-replication server reports state "Waiting while replication worker thread pool is busy"

--connect(con1,localhost,root,,)

--let $conid= `select connection_id()`

--delimiter $

--send

  LOOP FLUSH TABLES WITH READ LOCK ; END LOOP $

--delimiter ;

--connection default

while (! $res)

{

  --let $res= `select * from information_schema.processlist where state = 'Waiting while replication worker thread pool is busy'`

}

--echo $res

--eval kill $conid

connect con1,localhost,root,,;

LOOP FLUSH TABLES WITH READ LOCK ; END LOOP $

connection default;

5	root	localhost	test	Query	0	Waiting while replication worker thread pool is busy	FLUSH TABLES WITH READ LOCK	0.060	0	0	0.000	75928	81072	0	186	FLUSH TABLES WITH READ LOCK	2476401

kill 5;