config root man

create table t1 (
a int,
b int not null,
c1 char(255),
c2 char(255),
key k1(b, c1, c2)
)
engine = ndb;
insert into t1(a,b,c1,c2) values
(0, 0, 0, 0),
(1, 1, 1, 1),
(2, 2, 2, 1),
(3, 3, 3, 3),
(4, 4, 4, 4),
(5, 5, 5, 5),
(6, 6, 6, 6),
(7, 7, 7, 7),
(8, 8, 8, 8),
(9, 9, 9, 9);
insert into t1 select a + 10,  b, c1, c2 from t1;
insert into t1 select a + 20,  b, c1, c2 from t1;
insert into t1 select a + 40,  b, c1, c2 from t1;
insert into t1 select a + 80,  b, c1, c2 from t1;
insert into t1 select a + 160, b, c1, c2 from t1;
insert into t1 select a + 320, b, c1, c2 from t1;
insert into t1 select a + 640, b, c1, c2 from t1;
insert into t1 select a + 1280, b, c1, c2 from t1;
explain
select * from t1 as x, t1 as y
where y.b = x.a and y.c1 = x.c1 and y.c2 = x.c1;
id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	x	p0,p1,p2,p3,p4,p5,p6,p7	ALL	NULL	NULL	NULL	NULL	2560	100.00	Parent of 2 pushed join@1; Using where with pushed condition ((`test`.`x`.`a` is not null) and (`test`.`x`.`c1` is not null) and (`test`.`x`.`c1` is not null))
1	SIMPLE	y	p0,p1,p2,p3,p4,p5,p6,p7	ref	k1	k1	516	test.x.a,test.x.c1,test.x.c1	10	100.00	Child of 'x' in pushed join@1
Warnings:
Note	1003	/* select#1 */ select `test`.`x`.`a` AS `a`,`test`.`x`.`b` AS `b`,`test`.`x`.`c1` AS `c1`,`test`.`x`.`c2` AS `c2`,`test`.`y`.`a` AS `a`,`test`.`y`.`b` AS `b`,`test`.`y`.`c1` AS `c1`,`test`.`y`.`c2` AS `c2` from `test`.`t1` `x` join `test`.`t1` `y` where ((`test`.`y`.`c1` = `test`.`x`.`c1`) and (`test`.`y`.`c2` = `test`.`x`.`c1`) and (`test`.`y`.`b` = `test`.`x`.`a`))
select count(*) from t1 as x, t1 as y
where y.b = x.a and y.c1 = x.c1 and y.c2 = x.c1;
count(*)
2304
drop table t1;