MDEV-22934 Table disappear after two alter table command

Problem: ======= InnoDB drops the column which has foreign key relations on it. So it tries to load the foreign key during rename process of copy algorithm even though the foreign_key_check is disabled. Solution: ======== During alter copy algorithm, InnoDB ignores the error while loading the foreign key constraint if foreign key check is disabled. It should throw the warning about failure of the foreign key constraint when foreign key check is disabled.

Author: Thirunarayanan

mysql-test/suite/innodb/r/foreign_key.result

@@ -659,6 +659,7 @@ SET GLOBAL innodb_purge_rseg_truncate_frequency = @saved_frequency;
 # MDEV-17187 table doesn't exist in engine after ALTER other tables
 # with CONSTRAINTs
 #
+call mtr.add_suppression("\\[Warning\\] InnoDB: In ALTER TABLE `test`\\.`t2` has or is referenced in foreign key constraints which are not compatible with the new table definition.");
 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,
@@ -714,4 +715,30 @@ 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'
+#
+# MDEV-22934 Table disappear after two alter table command
+#
+CREATE TABLE t1(f1 INT NOT NULL AUTO_INCREMENT,
+f2 INT NOT NULL,
+PRIMARY KEY (f1), INDEX (f2))ENGINE=InnoDB;
+CREATE TABLE t2(f1 INT NOT NULL,
+f2 INT NOT NULL, f3 INT NOT NULL,
+PRIMARY KEY(f1, f2), UNIQUE KEY(f2),
+CONSTRAINT `t2_ibfk_1` FOREIGN KEY (f2) REFERENCES t1(f2) ON DELETE CASCADE,
+CONSTRAINT `t2_ibfk_2` FOREIGN KEY (f1) REFERENCES t1(f1) ON DELETE CASCADE
+) ENGINE=InnoDB;
+SET FOREIGN_KEY_CHECKS=0;
+ALTER TABLE t2 DROP PRIMARY KEY, ADD PRIMARY KEY(f3), ALGORITHM=INPLACE;
+ALTER TABLE t2 DROP INDEX `f2`, ALGORITHM=COPY;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+ `f1` int(11) NOT NULL,
+ `f2` int(11) NOT NULL,
+ `f3` int(11) NOT NULL,
+ PRIMARY KEY (`f3`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
+CREATE TABLE t2 (f1 INT NOT NULL)ENGINE=InnoDB;
+ERROR 42S01: Table 't2' already exists
+DROP TABLE t2, t1;
 # End of 10.2 tests

mysql-test/suite/innodb/r/innodb.result

@@ -2598,7 +2598,6 @@ set foreign_key_checks=0;
 create table t2 (a varchar(10), foreign key (a) references t1(a)) engine = innodb;
 create table t1(a varchar(10) primary key) engine = innodb;
 alter table t1 modify column a int;
-Got one of the listed errors
 set foreign_key_checks=1;
 drop table t2,t1;
 set foreign_key_checks=0;
@@ -2607,6 +2606,7 @@ create table t1(a varchar(10) primary key) engine = innodb DEFAULT CHARSET=latin
 alter table t1 convert to character set utf8;
 set foreign_key_checks=1;
 drop table t2,t1;
+call mtr.add_suppression("\\[Warning\\] InnoDB: In ALTER TABLE `test`.`t1` has or is referenced in foreign key constraints which are not compatible with the new table definition.");
 set foreign_key_checks=0;
 create table t2 (a varchar(10), foreign key (a) references t1(a)) engine = innodb DEFAULT CHARSET=latin1;
 create table t3(a varchar(10) primary key) engine = innodb DEFAULT CHARSET=utf8;

mysql-test/suite/innodb/t/foreign_key.test

@@ -657,6 +657,8 @@ SET GLOBAL innodb_purge_rseg_truncate_frequency = @saved_frequency;
 --echo # with CONSTRAINTs
 --echo #
 
+call mtr.add_suppression("\\[Warning\\] InnoDB: In ALTER TABLE `test`\\.`t2` has or is referenced in foreign key constraints which are not compatible with the new table definition.");
+
 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,
@@ -698,6 +700,27 @@ drop table t1,t2;
 --error ER_BAD_TABLE_ERROR
 drop table t1,t2;
 
+--echo #
+--echo # MDEV-22934 Table disappear after two alter table command
+--echo #
+CREATE TABLE t1(f1 INT NOT NULL AUTO_INCREMENT,
+f2 INT NOT NULL,
+PRIMARY KEY (f1), INDEX (f2))ENGINE=InnoDB;
+CREATE TABLE t2(f1 INT NOT NULL,
+f2 INT NOT NULL, f3 INT NOT NULL,
+PRIMARY KEY(f1, f2), UNIQUE KEY(f2),
+CONSTRAINT `t2_ibfk_1` FOREIGN KEY (f2) REFERENCES t1(f2) ON DELETE CASCADE,
+CONSTRAINT `t2_ibfk_2` FOREIGN KEY (f1) REFERENCES t1(f1) ON DELETE CASCADE
+) ENGINE=InnoDB;
+
+SET FOREIGN_KEY_CHECKS=0;
+ALTER TABLE t2 DROP PRIMARY KEY, ADD PRIMARY KEY(f3), ALGORITHM=INPLACE;
+ALTER TABLE t2 DROP INDEX `f2`, ALGORITHM=COPY;
+SHOW CREATE TABLE t2;
+--error ER_TABLE_EXISTS_ERROR
+CREATE TABLE t2 (f1 INT NOT NULL)ENGINE=InnoDB;
+DROP TABLE t2, t1;
+
 --echo # End of 10.2 tests
 
 --source include/wait_until_count_sessions.inc

mysql-test/suite/innodb/t/innodb.test

@@ -1662,7 +1662,6 @@ drop table t1;
 set foreign_key_checks=0;
 create table t2 (a varchar(10), foreign key (a) references t1(a)) engine = innodb;
 create table t1(a varchar(10) primary key) engine = innodb;
--- error 1025,1025
 alter table t1 modify column a int;
 set foreign_key_checks=1;
 drop table t2,t1;
@@ -1678,6 +1677,7 @@ drop table t2,t1;
 
 # test that RENAME does not allow invalid charsets when f_k_c is 0
 
+call mtr.add_suppression("\\[Warning\\] InnoDB: In ALTER TABLE `test`.`t1` has or is referenced in foreign key constraints which are not compatible with the new table definition.");
 set foreign_key_checks=0;
 create table t2 (a varchar(10), foreign key (a) references t1(a)) engine = innodb DEFAULT CHARSET=latin1;
 create table t3(a varchar(10) primary key) engine = innodb DEFAULT CHARSET=utf8;

storage/innobase/row/row0mysql.cc

@@ -4536,12 +4536,20 @@ row_rename_table_for_mysql(
 if (err != DB_SUCCESS) {
 
 if (old_is_tmp) {
-ib::error() << "In ALTER TABLE "
+/* In case of copy alter, ignore the
+loading of foreign key constraint
+when foreign_key_check is disabled */
+ib::error_or_warn(trx->check_foreigns)
+<< "In ALTER TABLE "
 << ut_get_name(trx, new_name)
 << " has or is referenced in foreign"
 " key constraints which are not"
 " compatible with the new table"
 " definition.";
+if (!trx->check_foreigns) {
+err = DB_SUCCESS;
+goto funct_exit;
+}
 } else {
 ib::error() << "In RENAME TABLE table "
 << ut_get_name(trx, new_name)