empty result when query contains "in (v1, v2 .. )"

[ChenPeng2013]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

use test;
drop table if exists IDT_RP2205;
CREATE TABLE `IDT_RP2205` (   `COL1` tinyint(11) DEFAULT '24' COMMENT 'NUMERIC UNIQUE INDEX') ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin PARTITION BY RANGE ( `COL1`%44 ) (   PARTITION `P0` VALUES LESS THAN (0),   PARTITION `P1` VALUES LESS THAN (10),   PARTITION `P2` VALUES LESS THAN (20),   PARTITION `P3` VALUES LESS THAN (30),   PARTITION `P4` VALUES LESS THAN (40),   PARTITION `P5` VALUES LESS THAN (50),   PARTITION `PMX` VALUES LESS THAN (MAXVALUE) );
insert into IDT_RP2205 values(127);
select * from IDT_RP2205 where col1 in (127);
select * from IDT_RP2205 where col1 in (127,127);

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

mysql> select * from IDT_RP2205 where col1 in (127);
+------+
| COL1 |
+------+
|  127 |
+------+
1 row in set (0.01 sec)

mysql> select * from IDT_RP2205 where col1 in (127,127);
+------+
| COL1 |
+------+
|  127 |
+------+

3. What did you see instead (Required)

mysql> select * from IDT_RP2205 where col1 in (127);
+------+
| COL1 |
+------+
|  127 |
+------+
1 row in set (0.01 sec)

mysql> select * from IDT_RP2205 where col1 in (127,127);
Empty set (0.00 sec)

4. What is your TiDB version? (Required)

master 3edbab3 and release-5.0-rc 760c7d1

[guo-shaoge]

/assign @guo-shaoge

[crazycs520]

related issue: #22898 @tiancaiamao PTAL

[guo-shaoge]

We got bug in partition prune for in expr. We directly use 127 to get partition, but actually we should use 127%xxx.

mysql> explain select * from IDT_RP2205 where col1 in (127,127);
+-------------------------+----------+-----------+---------------------------------+------------------------------------+
| id                      | estRows  | task      | access object                   | operator info                      |
+-------------------------+----------+-----------+---------------------------------+------------------------------------+
| TableReader_9           | 10.00    | root      |                                 | data:Selection_8                   |
| └─Selection_8           | 10.00    | cop[tikv] |                                 | in(test.idt_rp2205.col1, 127, 127) |
|   └─TableFullScan_7     | 10000.00 | cop[tikv] | table:IDT_RP2205, partition:pmx | keep order:false, stats:pseudo     |
+-------------------------+----------+-----------+---------------------------------+------------------------------------+
3 rows in set (0.00 sec)

mysql> explain select * from IDT_RP2205 where col1 in (127);
+-------------------------+---------+-----------+--------------------------------+--------------------------------+
| id                      | estRows | task      | access object                  | operator info                  |
+-------------------------+---------+-----------+--------------------------------+--------------------------------+
| TableReader_9           | 0.00    | root      |                                | data:Selection_8               |
| └─Selection_8           | 0.00    | cop[tikv] |                                | eq(test.idt_rp2205.col1, 127)  |
|   └─TableFullScan_7     | 1.00    | cop[tikv] | table:IDT_RP2205, partition:p1 | keep order:false, stats:pseudo |
+-------------------------+---------+-----------+--------------------------------+--------------------------------+
3 rows in set (0.00 sec)

PS: why the second plan is correct: in expr is rewrite as equal expr.

[ti-srebot]

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1. Root Cause Analysis (RCA) (optional)

2. Symptom (optional)

3. All Trigger Conditions (optional)

4. Workaround (optional)

5. Affected versions

[v4.0.0:v4.0.11],[v5.0.0-rc]

6. Fixed versions

master