tidb-4.0 should not support invisible index syntax

[marsishandsome]

Bug Report

tidb-4.0 should not support invisible index syntax

1. Minimal reproduce step (Required)

drop table t_invisible_index;
create table t_invisible_index(a int, index idx_a(a));
alter table t_invisible_index alter index idx_a invisible;

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

MySQL [test]> drop table if exists t_invisible_index
-> ;
Query OK, 0 rows affected (0.22 sec)

MySQL [test]> drop table if exists t_invisible_index;
Query OK, 0 rows affected (0.00 sec)

MySQL [test]> create table t_invisible_index(a int, index idx_a(a));
Query OK, 0 rows affected (0.07 sec)

MySQL [test]> alter table t_invisible_index alter index idx_a invisible;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your TiDB version for the right syntax to use line 1 column 41 near "index idx_a invisible"

3. What did you see instead (Required)

MySQL [test]> drop table t_invisible_index;
Query OK, 0 rows affected (0.19 sec)

MySQL [test]> create table t_invisible_index(a int, index idx_a(a));
Query OK, 0 rows affected (0.08 sec)

MySQL [test]> alter table t_invisible_index alter index idx_a invisible;
Query OK, 0 rows affected (0.00 sec)

MySQL [test]> show create table t_invisible_index;
+-------------------+------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table |
+-------------------+------------------------------------------------------------------------------------------------------------------------------------------------+
| t_invisible_index | CREATE TABLE t_invisible_index (
a int(11) DEFAULT NULL,
KEY idx_a (a)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+-------------------+------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

4. What is your TiDB version? (Required)

Release Version: v4.0.5
Edition: Community
Git Commit Hash: 9c1c212
Git Branch: heads/refs/tags/v4.0.5
UTC Build Time: 2020-08-28 10:07:42
GoVersion: go1.13
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false

[lhy1024]

/label sig/execution

[bb7133]

Hi @marsishandsome , this is actually expected because, for most syntaxes, we support it in the parser firstly to 'improve the compatibility'. You can see this issue: #11486 for more details.