Could insert duplicate values into a unique index with global index

[Defined2014]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

set tidb_enable_global_index=true;
CREATE TABLE `t` (
  `a` int(11) NOT NULL,
  `b` int(11) DEFAULT NULL,
  `c` int(11) DEFAULT NULL,
  PRIMARY KEY (`a`) /*T![clustered_index] CLUSTERED */,
  UNIQUE KEY `idx1` (`b`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin
PARTITION BY HASH (`a`) PARTITIONS 5;

begin;
insert into t values (1, 2, 3);
insert into t values (2, 2, 3);

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

mysql> insert into t values (2, 2, 3);
ERROR 1062 (23000): Duplicate entry '2' for key 't.idx1'

3. What did you see instead (Required)

insert success

4. What is your TiDB version? (Required)

mysql> select tidb_version();
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tidb_version()                                                                                                                                                                                                                                                           |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Release Version: v8.0.0-alpha-719-gc7d4c9cebb
Edition: Community
Git Commit Hash: c7d4c9cebb207bf5bf4dd4e532c44fe9ad753774
Git Branch: master
UTC Build Time: 2024-04-07 08:23:01
GoVersion: go1.21.5
Race Enabled: false
Check Table Before Drop: false
Store: unistore |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

[Defined2014]

Caused by #42312, but it still has some problems.

A test case, it should return error

create table test_global ( a int, b int, c int)
partition by range( a ) (
	partition p1 values less than (10),
	partition p2 values less than (20),
	partition p3 values less than (30)
);
alter table test_global add unique index idx_b (b);
begin;
insert into test_global values (1, 1, 1), (8, 8, 8), (11, 11, 11), (12, 12, 12);
update test_global set a = 2, b = 12 where a = 11; -- it should return error