# Checking stack usage
#
# basic tests
#
select variable_value > 0 from information_schema.session_status where variable_name="stack_usage";
variable_value > 0
1
#
# Ensure stack usage is same for each iteration when using WITH recursive
#
create table t1
WITH recursive Fibonacci(PrevN, N, Stack) AS
(
SELECT 0, 1, 0
UNION ALL
SELECT N, PrevN + N, (select variable_value from information_schema.session_status where variable_name="stack_usage")
FROM Fibonacci
WHERE N < 100000
)
SELECT PrevN as N, Stack FROM Fibonacci;
select (select stack from t1 where n=2) = (select stack from t1 where N=75025) as c;
c
1
DROP table t1;
#
# Check stack with recursion
#
set @@max_sp_recursion_depth=20;
create or replace procedure recursion(x int, max int, OUT res int)
begin
select variable_value into res from information_schema.session_status where variable_name="stack_usage";
if (x < max) then
call recursion(x+1, max, res);
end if;
end;
$$
call recursion(0,2,@s1);
call recursion(0,3,@s2);
call recursion(0,4,@s3);
select @s1 > 0 && @s2 > 0 && @s3 > 0;
@s1 > 0 && @s2 > 0 && @s3 > 0
1
drop procedure recursion;
#
# End of 10.5 tests
#