stop slave;
drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
reset master;
reset slave;
drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
start slave;
create table t1(n int);
insert into t1 values(get_lock("lock",2));
select get_lock("lock",2);
get_lock("lock",2)
1
select release_lock("lock");
release_lock("lock")
1
select get_lock("lock",3);
get_lock("lock",3)
1
select * from t1;
n
1
select is_free_lock("lock"), is_used_lock("lock") = connection_id();
is_free_lock("lock")	is_used_lock("lock") = connection_id()
0	1
explain extended select is_free_lock("lock"), is_used_lock("lock");
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
Warnings:
Note	1003	select is_free_lock(_latin1'lock') AS `is_free_lock("lock")`,is_used_lock(_latin1'lock') AS `is_used_lock("lock")`
select is_free_lock("lock2");
is_free_lock("lock2")
1
select is_free_lock(NULL);
is_free_lock(NULL)
NULL
drop table t1;