Data too long when setting @@tidb_cloud_storage_uri

[tangenta]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

Previously, global variable value cannot have more than 1024 characters:

mysql> desc mysql.global_variables;
+----------------+---------------+------+------+---------+-------+
| Field          | Type          | Null | Key  | Default | Extra |
+----------------+---------------+------+------+---------+-------+
| VARIABLE_NAME  | varchar(64)   | NO   | PRI  | NULL    |       |
| VARIABLE_VALUE | varchar(1024) | YES  |      | NULL    |       |
+----------------+---------------+------+------+---------+-------+
2 rows in set (0.00 sec)

However, S3 URI is easy to exceed 1024 if it consists of multiple query parameters.

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

No error.

3. What did you see instead (Required)

ERROR 1406 (22001): Data too long for column 'VARIABLE_VALUE' at row 1; 

4. What is your TiDB version? (Required)

9224f62