SET STORAGE_ENGINE = 'tokudb';
DROP TABLE IF EXISTS t1,t2;
#
# Bug#50843: Filesort used instead of clustered index led to
#            performance degradation.
#
create table t1(f1 int not null primary key, f2 int);
create table t2(f1 int not null, key (f1));
insert into t1 values (1,1),(2,2),(3,3);
insert into t2 values (1),(2),(3);
explain select t1.* from t1 left join t2 using(f1) group by t1.f1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	NULL	PRIMARY	4	NULL	1	
1	SIMPLE	t2	ref	f1	f1	4	test.t1.f1	2	Using index
alter table t1 drop primary key;
alter table t1 add clustering index (f1);
explain select t1.* from t1 left join t2 using(f1) group by t1.f1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	NULL	f1	4	NULL	1	
1	SIMPLE	t2	ref	f1	f1	4	test.t1.f1	2	Using index
drop table t1,t2;
#