flush status;
show status like 'Table_lock%';
Variable_name	Value
Table_locks_immediate	0
Table_locks_waited	0
SET SQL_LOG_BIN=0;
drop table if exists t1;
create table t1(n int) engine=myisam;
insert into t1 values(1);
lock tables t1 read;
unlock tables;
lock tables t1 read;
update t1 set n = 3;
unlock tables;
show status like 'Table_lock%';
Variable_name	Value
Table_locks_immediate	3
Table_locks_waited	1
drop table t1;
