[Bug]: alter add foreign key concurrent 50 threads reported w-w conflict error

[heni02]

Is there an existing issue for the same bug?

• I have checked the existing issues.

Branch Name

2.0-dev

Commit ID

d570bbd

Other Environment Information

- Hardware parameters:
- OS type:
- Others:

Actual Behavior

测试场景：alter table add foreign key并发50执行5分钟
测试结果：sql报错w-w conflict
测试sql：alter table table_{id} add constraint fk_{id} foreign key(col2) references fk_01(col1);（100个表创建外键依赖fk_01 col1列）

单独顺序执行是可以的

ddl：
create table concurrent_test.fk_01(col1 int not null primary key,col2 int);insert into concurrent_test.fk_01 values (90,5983),(100,734),(190,50);
create table concurrent_test.table_$i(col1 bigint primary key auto_increment,col2 int)

另外同时并发alter add foreign和alter drop foreign key测试，两个sql也是会报w-w conflict

Expected Behavior

No response

Steps to Reproduce

1. git clone mo-load工具
2. 准备mo 100个表数据：
 mysql -h 127.0.0.1 -udump -P6001 -p111 -e "drop database if exists concurrent_test;create database concurrent_test;create table concurrent_test.fk_01(col1 int not null primary key,col2 int);insert into concurrent_test.fk_01 values (90,5983),(100,734),(190,50);"

for i in {1..100}; do mysql -h 127.0.0.1 -udump -P6001 -p111 -e "create table concurrent_test.table_$i(col1 bigint primary key auto_increment,col2 int)";done
3.执行并发50测试
cd mo-load
./start.sh -h 127.0.0.1  -b concurrent_test -c cases/ddl/alter_add_drop_foreign_key/ （此命令是同时并发alter add和drop foreign key，如果只单独并发alter add，vim cases/ddl/alter_add_drop_foreign_key/run.yaml删除-name："alter_drop_fk"以下一段case，再执行该命令即可）

如果

Additional information

No response

[ouyuanning]

根本原因是当设计到外键的时候。是有更改外键表的schema的。而没有给外键表加锁造成的