batch_cop with union_scan return wrong result when using dynamic partition prune

[windtalker]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

mysql> show create table employees;
+-----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table     | Create Table                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
+-----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| employees | CREATE TABLE `employees` (
  `id` int(11) NOT NULL,
  `fname` varchar(30) DEFAULT NULL,
  `lname` varchar(30) DEFAULT NULL,
  `hired` date NOT NULL DEFAULT '1970-01-01',
  `separated` date DEFAULT '9999-12-31',
  `job_code` int(11) DEFAULT NULL,
  `store_id` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin
PARTITION BY RANGE (`store_id`)
(PARTITION `p0` VALUES LESS THAN (6),
 PARTITION `p1` VALUES LESS THAN (11),
 PARTITION `p2` VALUES LESS THAN (16),
 PARTITION `p3` VALUES LESS THAN (21),
 PARTITION `p4` VALUES LESS THAN (MAXVALUE)) |
+-----------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
mysql> alter table test.employees set tiflash replica 1;
mysql> set tidb_partition_prune_mode=dynamic; begin; insert into test.employees values(100,'aa','aa','2020-01-01',null,10,10); set session tidb_allow_batch_cop=2; select count(*) from test.employees;
+----------+
| count(*) |
+----------+
|        0 |
+----------+

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

mysql> set tidb_partition_prune_mode=dynamic; begin; insert into test.employees values(100,'aa','aa','2020-01-01',null,10,10); set session tidb_allow_batch_cop=2; select count(*) from test.employees;
+----------+
| count(*) |
+----------+
|        1 |
+----------+

3. What did you see instead (Required)

mysql> set tidb_partition_prune_mode=dynamic; begin; insert into test.employees values(100,'aa','aa','2020-01-01',null,10,10); set session tidb_allow_batch_cop=2; select count(*) from test.employees;
+----------+
| count(*) |
+----------+
|        0 |
+----------+

4. What is your TiDB version? (Required)

master @ 41fb3e7