P2-[4.0 Bug Hunting]-[hex function]-missing padding zeros

[sre-bot]

Description

Bug Hunter issue tidb-challenge-program/bug-hunting-issue#82

---

Bug Report

1. What did you do?

create table table1 (col1 binary(4));
insert into table1 values ('a'),('a ');
select hex(col1) from table1;
alter table table1 modify col1 binary(10);
select hex(col1) from table1;
insert into table1 values ('b'),('b ');
select hex(col1) from table1;

2. What did you expect to see?

mysql> create table table1 (col1 binary(4));
Query OK, 0 rows affected (0.02 sec)

mysql> insert into table1 values ('a'),('a ');
Query OK, 2 rows affected (0.01 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> select hex(col1) from table1;
+-----------+
| hex(col1) |
+-----------+
| 61000000  |
| 61200000  |
+-----------+
2 rows in set (0.00 sec)

mysql> alter table table1 modify col1 binary(10);
Query OK, 2 rows affected (0.13 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> select hex(col1) from table1;
+----------------------+
| hex(col1)            |
+----------------------+
| 61000000000000000000 |
| 61200000000000000000 |
+----------------------+
2 rows in set (0.00 sec)

mysql> insert into table1 values ('b'),('b ');
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> select hex(col1) from table1;
+----------------------+
| hex(col1)            |
+----------------------+
| 61000000000000000000 |
| 61200000000000000000 |
| 62000000000000000000 |
| 62200000000000000000 |
+----------------------+
4 rows in set (0.00 sec)

3. What did you see instead?

mysql> create table table1 (col1 binary(4));
Query OK, 0 rows affected (0.01 sec)

mysql> insert into table1 values ('a'),('a ');
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> select hex(col1) from table1;
+-----------+
| hex(col1) |
+-----------+
| 61000000  |
| 61200000  |
+-----------+
2 rows in set (0.00 sec)

mysql> alter table table1 modify col1 binary(10);
Query OK, 0 rows affected (0.01 sec)

mysql> select hex(col1) from table1;
+-----------+
| hex(col1) |
+-----------+
| 61000000  |
| 61200000  |
+-----------+
2 rows in set (0.00 sec)

mysql> insert into table1 values ('b'),('b ');
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> select hex(col1) from table1;
+----------------------+
| hex(col1)            |
+----------------------+
| 61000000             |
| 61200000             |
| 62000000000000000000 |
| 62200000000000000000 |
+----------------------+
4 rows in set (0.00 sec)

4. What version of TiDB are you using? (tidb-server -V or run select tidb_version(); on TiDB)

Reproducible on master branch:

commit 0d33a845766733fbb9e40dae8b7bf38fb0d3498b (HEAD -> master, origin/master, origin/HEAD)
Author: Zhuomin(Charming) Liu <lzmhhh123@gmail.com>
Date:   Wed May 20 19:54:37 2020 +0800

select tidb_version();

mysql> select tidb_version();
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tidb_version()                                                                                                                                                                                                                           |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Release Version: None
Edition: None
Git Commit Hash: None
Git Branch: None
UTC Build Time: None
GoVersion: go1.13.4
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false |
+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

SIG slack channel

#sig-exec

Score

• 300

Mentor

• @lzmhhh123

[ghost]

Related to #3644

[ou-bing]

/pick-up

[ti-challenge-bot]

Pick up success.

[ti-challenge-bot]

@ou-bing You did not submit PR within 7 days, so give up automatically.

[wjhuang2016]

Duplicate with #3644