Query cache makes virtual column function RAND() non-random

set global query_cache_type=1;

set query_cache_type=1;

create table t (a int, b float as (rand()));

insert into t (a) values (1);

select * from t;

a	b

1	0.181048

select * from t;

a	b

1	0.181048

set query_cache_type=0;

select * from t;

a	b

1	0.437779