SET @saved_dbug = @@SESSION.debug_dbug;
set session debug_dbug="+d,optimizer_innodb_icp";
create table `t1` (`c1` char(1) default null,`c2` char(10) default null,
key (`c1`))
engine=innodb default charset=latin1;
insert into `t1` values ('3',null);
select * from `t1` where `c1`='3' for update;
c1	c2
3	NULL
drop table `t1`;
SET debug_dbug= @saved_dbug;