Unsupported modify charset from latin1 to utf8mb4

[bestwoody]

Working Progress

Implementation

• *: Support modify table/column charset from latin1 to utf8/utf8mb4 #34386
• Support check invalid utf8 characters during Alter table ... charset stmts #34562
• Support reorg invalid characters

Bugs

• forbid alter latin1 to utf8mb3 #34720

Docs

• Update releated docs update latin1 as an alias for utf8mb4 docs-cn#9522

Bug Report

Unsupported modify charset from latin1 to utf8mb4

1. Minimal reproduce step (Required)

MySQL [test]> create table t2(a varchar(20) )CHARSET=latin1;
MySQL [test]> insert into t2 values('😊');
MySQL [test]> alter table t2 DEFAULT CHARACTER SET utf8mb4;

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

Query OK

3. What did you see instead (Required)

ERROR 8200 (HY000): Unsupported modify charset from latin1 to utf8mb4

4. What is your TiDB version? (Required)

v5.2.2

[wjhuang2016]

We don't have a plan to support it in a short time.

[bestwoody]

We don't have a plan to support it in a short time.

this affects POC user.

[xiongjiwei]

MySQL [test]> create table t3 (a varchar(20)) charset=utf8mb4;
MySQL [test]> insert into t3 select * from t2;

this shall work