Recursive CTE: view usage between 2 same query executions changes explain NOTE

create table t1; insert into table ...

explain exended with_recursive_query;

create view v1 as with_recursive_query; select * from v1;

drop view v1;

explain extended with_recursive_query;

set default_storage_engine=myisam;

create table  folks(id int, name char(32), dob date, father int, mother int) charset=latin1;

insert into folks values

(100, 'Me', '2000-01-01', 20, 30),

(20, 'Dad', '1970-02-02', 10, 9),

(30, 'Mom', '1975-03-03', 8, 7),

(10, 'Grandpa Bill', '1940-04-05', null, null),

(9, 'Grandma Ann', '1941-10-15', null, null),

(25, 'Uncle Jim', '1968-11-18', 8, 7),

(98, 'Sister Amy', '2001-06-20', 20, 30),

(7, 'Grandma Sally', '1943-08-23', null, 6),

(8, 'Grandpa Ben', '1940-10-21', null, null),

(6, 'Grandgrandma Martha', '1923-05-17', null, null),

(67, 'Cousin Eddie', '1992-02-28', 25, 27),

(27, 'Auntie Melinda', '1971-03-29', null, null);

let $q= with recursive 

ancestors

as

(

  select *

    from folks

      where name = 'Me' and dob = '2000-01-01'

  union 

  select p.id, p.name, p.dob, p.father, p.mother

    from folks as p, ancestors AS a

      where p.id = a.father or p.id = a.mother

)

select * from ancestors;

eval explain extended $q;

eval create view v1 as $q;

show create view v1;

select * from v1;

drop view v1;

eval explain extended $q;

drop table folks;