Query with distinct got wrong result

[pcqz]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

https://asktug.com/t/topic/93576

CREATE TABLE test_distinct (
id bigint(18) NOT NULL COMMENT '主键',
b bigint(18) NOT NULL COMMENT '用户ID',
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
insert into test_distinct values
(123456789101112131,223456789101112131),(123456789101112132,223456789101112131);

select distinct b from test_distinct where id in (123456789101112131,123456789101112132);

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

+--------------------+
| b                  |
+--------------------+
| 223456789101112131 |
+--------------------+
1 row in set (0.01 sec)

3. What did you see instead (Required)

+--------------------+
| b                  |
+--------------------+
| 223456789101112131 |
| 223456789101112131 |
+--------------------+
2 rows in set (0.01 sec)

4. What is your TiDB version? (Required)

v5.0.1

[xiongjiwei]

mysql> desc select distinct b from test_distinct where id in (123456789101112131,123456789101112132);
+-------------------+---------+------+----------------------------------------+------------------------------+
| id                | estRows | task | access object                          | operator info                |
+-------------------+---------+------+----------------------------------------+------------------------------+
| Batch_Point_Get_1 | 2.00    | root | table:test_distinct, index:PRIMARY(id) | keep order:false, desc:false |
+-------------------+---------+------+----------------------------------------+------------------------------+
1 row in set (0.00 sec)

mysql> desc select distinct b from test_distinct;
+--------------------------+----------+-----------+---------------------+-------------------------------------------------------------------------------------------+
| id                       | estRows  | task      | access object       | operator info                                                                             |
+--------------------------+----------+-----------+---------------------+-------------------------------------------------------------------------------------------+
| HashAgg_6                | 8000.00  | root      |                     | group by:test.test_distinct.b, funcs:firstrow(test.test_distinct.b)->test.test_distinct.b |
| └─TableReader_11         | 10000.00 | root      |                     | data:TableFullScan_10                                                                     |
|   └─TableFullScan_10     | 10000.00 | cop[tikv] | table:test_distinct | keep order:false, stats:pseudo                                                            |
+--------------------------+----------+-----------+---------------------+-------------------------------------------------------------------------------------------+
3 rows in set (0.00 sec)

it's about point_get

[winoros]

Emm, distinct should not be converted to point get in the fast path.

[ti-srebot]

Please edit this comment or add a new comment to complete the following information

Not a bug

1. Remove the 'type/bug' label
2. Add notes to indicate why it is not a bug

Duplicate bug

1. Add the 'type/duplicate' label
2. Add the link to the original bug

Bug

Note: Make Sure that 'component', and 'severity' labels are added
Example for how to fill out the template: #20100

1. Root Cause Analysis (RCA) (optional)

2. Symptom (optional)

3. All Trigger Conditions (optional)

4. Workaround (optional)

5. Affected versions

6. Fixed versions