SET DEBUG_SYNC='reset';
create table t1 (f1 integer, key k1 (f1)) engine=innodb;
create table t2 (f1 int, f2 int, key(f1), key(f2)) engine=innodb;
create table t3 (f2 int, key(f2)) engine=innodb;
insert into t1 values (10);
insert into t2 values (10, 20);
insert into t3 values (20);
alter table t2 add constraint c1 foreign key (f1)
references t1(f1) on update cascade;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`f1` int(11) DEFAULT NULL,
KEY `k1` (`f1`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`f1` int(11) DEFAULT NULL,
`f2` int(11) DEFAULT NULL,
KEY `f1` (`f1`),
KEY `f2` (`f2`),
CONSTRAINT `c1` FOREIGN KEY (`f1`) REFERENCES `t1` (`f1`) ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=latin1
show create table t3;
Table Create Table
t3 CREATE TABLE `t3` (
`f2` int(11) DEFAULT NULL,
KEY `f2` (`f2`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
SET DEBUG_SYNC='innodb_rename_table_ready SIGNAL update_can_proceed
WAIT_FOR dict_unfreeze';
alter table t2 add constraint z1 foreign key (f2)
references t3(f2) on update cascade;
SET DEBUG_SYNC='innodb_row_update_for_mysql_begin
WAIT_FOR update_can_proceed';
SET DEBUG_SYNC='innodb_dml_cascade_dict_unfreeze SIGNAL dict_unfreeze
WAIT_FOR foreign_free_cache';
update ignore t1 set f1 = 20;
ERROR HY000: Error on rename of './test/t2' to '#sql2-temporary' (errno: 183 - Table is being used in foreign key check)
SET DEBUG_SYNC='now SIGNAL foreign_free_cache';
drop table t2;
drop table t1;
drop table t3;
SET DEBUG_SYNC='reset';