TiDB returns wrong result for cartesian join

[windtalker]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

mysql> show create table t1_1;
+-------+----------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                   |
+-------+----------------------------------------------------------------------------------------------------------------+
| t1_1  | CREATE TABLE `t1_1` (
  `col1` double DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+-------+----------------------------------------------------------------------------------------------------------------+
1 row in set (0.03 sec)

mysql> show create table t2_1;
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                                                      |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------+
| t2_1  | CREATE TABLE `t2_1` (
  `col1` varchar(20) DEFAULT NULL,
  `col2` double DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin |
+-------+---------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.04 sec)

mysql> select * from t1_1;
+--------+
| col1   |
+--------+
| 12.991 |
+--------+
1 row in set (0.06 sec)

mysql> select * from t2_1;
+------+--------+
| col1 | col2   |
+------+--------+
| NULL |     87 |
| NULL | -9.183 |
| NULL | -9.183 |
+------+--------+
3 rows in set (0.14 sec)
mysql> set session tidb_isolation_read_engines='tikv';
Query OK, 0 rows affected (0.04 sec)

mysql> explain select t1.col1, t2.col1, t2.col2 from t1_1 t1 inner join  t2_1 t2 on t1.col1 not in (1,t2.col1,t2.col2) order by 1,2,3;
+-------------------------------+---------+-----------+---------------+------------------------------------------------------------------------------------------------------------------+
| id                            | estRows | task      | access object | operator info                                                                                                    |
+-------------------------------+---------+-----------+---------------+------------------------------------------------------------------------------------------------------------------+
| Sort_8                        | 3.00    | root      |               | test.t1_1.col1, test.t2_1.col1, test.t2_1.col2                                                                   |
| └─HashJoin_12                 | 3.00    | root      |               | CARTESIAN inner join, other cond:not(in(test.t1_1.col1, 1, cast(test.t2_1.col1, double BINARY), test.t2_1.col2)) |
|   ├─TableReader_14(Build)     | 1.00    | root      |               | data:TableFullScan_13                                                                                            |
|   │ └─TableFullScan_13        | 1.00    | cop[tikv] | table:t1      | keep order:false, stats:pseudo                                                                                   |
|   └─TableReader_16(Probe)     | 3.00    | root      |               | data:TableFullScan_15                                                                                            |
|     └─TableFullScan_15        | 3.00    | cop[tikv] | table:t2      | keep order:false, stats:pseudo                                                                                   |
+-------------------------------+---------+-----------+---------------+------------------------------------------------------------------------------------------------------------------+
6 rows in set (0.04 sec)

mysql> select t1.col1, t2.col1, t2.col2 from t1_1 t1 inner join  t2_1 t2 on t1.col1 not in (1,t2.col1,t2.col2) order by 1,2,3;
+--------+------+--------+
| col1   | col1 | col2   |
+--------+------+--------+
| 12.991 | NULL | -9.183 |
| 12.991 | NULL | -9.183 |
+--------+------+--------+
2 rows in set (0.04 sec)

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

mysql> select t1.col1, t2.col1, t2.col2 from t1_1 t1 inner join  t2_1 t2 on t1.col1 not in (1,t2.col1,t2.col2) order by 1,2,3;
Empty set (0.00 sec)

3. What did you see instead (Required)

mysql> select t1.col1, t2.col1, t2.col2 from t1_1 t1 inner join  t2_1 t2 on t1.col1 not in (1,t2.col1,t2.col2) order by 1,2,3;
+--------+------+--------+
| col1   | col1 | col2   |
+--------+------+--------+
| 12.991 | NULL | -9.183 |
| 12.991 | NULL | -9.183 |
+--------+------+--------+
2 rows in set (0.04 sec)

4. What is your TiDB version? (Required)

mysql> select tidb_version();
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tidb_version()                                                                                                                                                                                                                                                                                                           |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Release Version: v5.2.0-alpha-14-g75388187f
Edition: Community
Git Commit Hash: 75388187f3865db18bc70ca1ef30260d85dba2e2
Git Branch: master
UTC Build Time: 2021-06-08 09:21:55
GoVersion: go1.16.4
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false |
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.06 sec)

[ChenPeng2013]

The latest version TiDB-v5.2.0-alpha-118-ga6f52fb45 does't have this issue

[windtalker]

I can reproduce it using the latest commit 58d8b960fa69fe829cf328fe486f8f14d0d9a2b3

[ChenPeng2013]

repro steps

use test;
drop table if exists t1_1, t2_1;
CREATE TABLE `t1_1` (
  `col1` double DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;
CREATE TABLE `t2_1` (
  `col1` varchar(20) DEFAULT NULL,
  `col2` double DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;
insert into t1_1 values(12.991);
insert into t2_1(col2) values(87), (-9.183), (-9.183);
analyze table t1_1;
analyze table t2_1;
select t1.col1, t2.col1, t2.col2 from t1_1 t1 inner join  t2_1 t2 on t1.col1 not in (1,t2.col1,t2.col2) order by 1,2,3;

[zz-jason]

@guo-shaoge PTAL

[guo-shaoge]

After (*builtinInRealSig) evalInt, OtherConditions in HashJoin become invalid.

Before: t1.c1 in (1, t2.c1, t2.c2)

After: t1.c1 in (t2.c2, t2.c2, t2.c2)

This code snippet describes what happend.

[ti-srebot]

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