Tikv lead function inconsistent behavior with tidb

[yibin87]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

set tidb_opt_projection_push_down = 'on';
CREATE TABLE t (c1 VARCHAR(10),
j1 JSON,
i1 INT,
b1 BLOB,
d1 DOUBLE,
e1 DECIMAL(5,4),
e2 DECIMAL(5,2));
INSERT INTO t VALUES (null, '[6]', 6, '6', 6.0, 10.0/3, 20.0/3),
('7', null , 7, '7', 7.0, 10.0/3, 20.0/3),
('8', '[8]' , 7, '8', 8.0, 10.0/3, 20.0/3),
('9', '[9]' , null, '9', 9.0, 10.0/3, 20.0/3),
('0', '[0]' , 0, null, 0.0, 10.0/3, 20.0/3),
('1', '[1]' , 1, '1', null, 10.0/3, 20.0/3),
('2', '[2]' , 2, '2', 2.0, null, 20.0/3),
('3', '[3]' , 3, '3', 3.0, 10.0/3, null);
SELECT LEAD(i1, 100, e1) OVER () lie1, IFNULL(i1, e1) ifn_ie1 FROM t;

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

lie1 ifn_ie1
3.3333 6.0000
3.3333 7.0000
3.3333 7.0000
3.3333 3.3333
3.3333 0.0000
3.3333 1.0000
NULL 2.0000
3.3333 3.0000

3. What did you see instead (Required)

3.3333 6
3.3333 7
3.3333 7
3.3333 3.3333
3.3333 0
3.3333 1
NULL 2
3.3333 3

4. What is your TiDB version? (Required)

| Release Version: v7.4.0-alpha-2012-gfe01d11df6-dirty
Edition: Community
Git Commit Hash: fe01d11
Git Branch: div_increase_prec
UTC Build Time: 2024-03-15 08:10:07

[yibin87]

Checked tidb's consistent with mysql.

[yibin87]

/assign @yibin87

[yibin87]

Narrow down the case:

mysql> SELECT IFNULL(i1, e1) ifn_ie1 FROM t;
+---------+
| ifn_ie1 |
+---------+
|       6 |
|       7 |
|       7 |
|  3.3333 |
|       0 |
|       1 |
|       2 |
|       3 |
+---------+
8 rows in set (0.00 sec)

[yibin87]

Should be closed by tikv/tikv#16914.

[yibin87]

Actually duplicated with #51879