Concurrent Column Type Change would cause inconsistent schema and data

[wjhuang2016]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

create table test(a int, b int);
insert into test values (1, 1);
alter table test change column b b double; /* in session 1 */
alter table test change column b b double; /* in session 2 */
select * from test;

2. What did you expect to see? (Required)

No error

3. What did you see instead (Required)

mysql> select * from test;
ERROR 1105 (HY000): insufficient bytes to decode value

4. What is your TiDB version? (Required)

5.1 5.2 5.3 master

[github-actions]

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