drop table if exists t1;
create table t1 (a int) engine=innodb;
begin;
insert into t1 values(1);
flush tables with read lock;
select * from t1;
a
 commit;
select * from t1;
a
unlock tables;
begin;
select * from t1 for update;
a
1
begin;
 select * from t1 for update;
 flush tables with read lock;
commit;
a
1
unlock tables;
drop table t1;