tidb: `length` result is wrong after modify column length

Description

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

create table t(a int, b binary(22));
insert into t set b='test';
alter table t modify b binary(33);
insert into t set b='test1';
select length(b) from t;

1. What did you expect to see?

+-----------+
| length(b) |
+-----------+
|        33 |
|        33 |
+-----------+

1. What did you see instead?

+-----------+
| length(b) |
+-----------+
|        22 |
|        33 |
+-----------+

1. What version of TiDB are you using (tidb-server -V)?

SIG slack channel

#sig-exec

Score

• 300

Mentor

• @qw4990