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MDEV-17187 table doesn't exist in engine after ALTER of FOREIGN KEY

ha_innobase::open(): Always ignore problems with FOREIGN KEY constraints
(pass DICT_ERR_IGNORE_FK_NOKEY), no matter whether foreign_key_checks
is enabled. Instead, we must report errors when enforcing the FOREIGN KEY
constraints. As a result of ignoring these errors, the tables will be
loaded with dict_foreign_t objects whose foreign_index or referenced_index
will be NULL.

Also, pass DICT_ERR_IGNORE_FK_NOKEY instead of DICT_ERR_IGNORE_NONE
to dict_table_open_on_id_low() in many other cases. Notably, on
CREATE TABLE and ALTER TABLE, we will keep validating the FOREIGN KEY
constraints as before.

dict_table_open_on_name(): If no other flags than
DICT_ERR_IGNORE_FK_NOKEY are set, refuse access to unreadable tables.
Some encryption tests rely on this code path.

For the DML code path, we used to have the problem that when
one of the indexes was missing in dict_foreign_t, we would ignore
the FOREIGN KEY constraint altogether. The following changes
address that.

row_ins_check_foreign_constraints(): Add the parameter pk.
For the primary key, consider also foreign key constraints for which
foreign->foreign_index=NULL (no underlying index is available).

row_ins_check_foreign_constraint(): Report errors also for !check_ref.
Remove a redundant check for srv_read_only_mode.

row_ins_foreign_report_add_err(): Tolerate foreign->foreign_index=NULL.
This commit is contained in:
Marko Mäkelä
2019-08-21 11:38:17 +03:00
parent e279c0076d
commit 9de2e60d74
10 changed files with 173 additions and 55 deletions

View File

@ -161,3 +161,62 @@ c d
6 30
drop table t2, t1;
drop user foo;
#
# MDEV-17187 table doesn't exist in engine after ALTER other tables
# with CONSTRAINTs
#
set foreign_key_checks=on;
create table t1 (id int not null primary key) engine=innodb;
create table t2 (id int not null primary key, fid int not null,
CONSTRAINT fk_fid FOREIGN KEY (fid) REFERENCES t1 (id))engine=innodb;
insert into t1 values (1), (2), (3);
insert into t2 values (1, 1), (2, 1), (3, 2);
set foreign_key_checks=off;
alter table t2 drop index fk_fid;
set foreign_key_checks=on;
delete from t1 where id=2;
ERROR 23000: Cannot delete or update a parent row: a foreign key constraint fails (`test`.`t2`, CONSTRAINT `fk_fid` FOREIGN KEY (`fid`) REFERENCES `t1` (`id`))
insert into t2 values(4, 99);
ERROR 23000: Cannot add or update a child row: a foreign key constraint fails (`test`.`t2`, CONSTRAINT `fk_fid` FOREIGN KEY (`fid`) REFERENCES `t1` (`id`))
select * from t1;
id
1
2
3
select * from t2;
id fid
1 1
2 1
3 2
set foreign_key_checks=off;
delete from t1 where id=2;
insert into t2 values(4, 99);
set foreign_key_checks=on;
select * from t1;
id
1
3
select * from t2;
id fid
1 1
2 1
3 2
4 99
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`id` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
show create table t2;
Table Create Table
t2 CREATE TABLE `t2` (
`id` int(11) NOT NULL,
`fid` int(11) NOT NULL,
PRIMARY KEY (`id`),
CONSTRAINT `fk_fid` FOREIGN KEY (`fid`) REFERENCES `t1` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
drop table t1,t2;
ERROR 23000: Cannot delete or update a parent row: a foreign key constraint fails
drop table t1,t2;
ERROR 42S02: Unknown table 'test.t2'