information_schema.variables_info DEFAULT_VALUE is incorrect

[together-wang]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

use variables_info to select DEFAULT_VALUE is incorrect.
for example tidb_enable_1pc and tidb_enable_async_commit's DEFAULT is on

mysql> select * from information_schema.variables_info where variable_name in ('tidb_enable_async_commit','tidb_enable_1pc');
+--------------------------+----------------+---------------+---------------+-----------+-----------+-----------------+---------+
| VARIABLE_NAME            | VARIABLE_SCOPE | DEFAULT_VALUE | CURRENT_VALUE | MIN_VALUE | MAX_VALUE | POSSIBLE_VALUES | IS_NOOP |
+--------------------------+----------------+---------------+---------------+-----------+-----------+-----------------+---------+
| tidb_enable_async_commit | SESSION,GLOBAL | OFF           | ON            |      NULL |      NULL | NULL            | NO      |
| tidb_enable_1pc          | SESSION,GLOBAL | OFF           | ON            |      NULL |      NULL | NULL            | NO      |
+--------------------------+----------------+---------------+---------------+-----------+-----------+-----------------+---------+
2 rows in set (0.01 sec)

mysql> show variables like 'tidb_enable_async_commit';
+--------------------------+-------+
| Variable_name            | Value |
+--------------------------+-------+
| tidb_enable_async_commit | ON    |
+--------------------------+-------+
1 row in set (0.01 sec)

mysql> show variables like 'tidb_enable_1pc';
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| tidb_enable_1pc | ON    |
+-----------------+-------+
1 row in set (0.00 sec)

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

information_schema.variables_info DEFAULT_VALUE show correctly

3. What did you see instead (Required)

4. What is your TiDB version? (Required)

master

mysql> select tidb_version();
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tidb_version()                                                                                                                                                                                                                                                             |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Release Version: v7.6.0-alpha
Edition: Community
Git Commit Hash: 918df0ae50568ebc54bd6d89f2d9a49bc9b79b06
Git Branch: heads/refs/tags/v7.6.0-alpha
UTC Build Time: 2023-12-14 04:07:56
GoVersion: go1.21.5
Race Enabled: false
Check Table Before Drop: false
Store: tikv |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

[together-wang]

/found gs