explain analyze causes wrong result when txn is too large

[you06]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

Run TiDB and load data with sysbench.

sysbench --config-file=config oltp_point_select --tables=1 --table-size=500000 prepare

Create table with same schema and load data by explain analyze insert select

create table sbtest2(id int(11) NOT NULL AUTO_INCREMENT, `k` int(11) NOT NULL DEFAULT '0',`c` char(120) NOT NULL DEFAULT '',`pad` char(60) NOT NULL DEFAULT '',PRIMARY KEY (`id`),KEY `k_1` (`k`));
explain analyze insert into sbtest2 select * from sbtest1;

P.S. if we just run insert select without explain analyze, it'll return txn-too-large error.

MySQL [test]> insert into sbtest2 select * from sbtest1;
ERROR 8004 (HY000): Transaction is too large, size: 104857766

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

If the statement execution succeeds, the data in sbtest2 should be the same as sbtest1.

MySQL [test]> select count(1) from sbtest2;
+----------+
| count(1) |
+----------+
|   500000 |
+----------+
1 row in set (2.857 sec)

MySQL [test]> select count(1) from sbtest1;
+----------+
| count(1) |
+----------+
|   500000 |
+----------+
1 row in set (0.242 sec)

3. What did you see instead (Required)

The data in sbtest2 is truncated.

MySQL [test]> select count(1) from sbtest2;
+----------+
| count(1) |
+----------+
|   412825 |
+----------+
1 row in set (2.857 sec)

MySQL [test]> select count(1) from sbtest1;
+----------+
| count(1) |
+----------+
|   500000 |
+----------+
1 row in set (0.242 sec)

The transaction details in TiDB dashboard are missing.

4. What is your TiDB version? (Required)

Release Version: v6.2.0-alpha
Edition: Community
Git Commit Hash: e2fd394fbfaf1ace2bb129c0e7863bd20f087152
Git Branch: heads/refs/tags/v6.2.0-alpha
UTC Build Time: 2022-05-31 14:58:00
GoVersion: go1.18.2
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false
Store: tikv

[zyguan]

A minimal reproducible case:

/* t */ drop table if exists t;
/* t */ create table t (a int primary key);
/* t */ insert into t values (2);
/* t */ set @@tidb_constraint_check_in_place=1;
/* t */ explain analyze insert into t values (1), (2), (3); -- ok
/* t */ select * from t; -- [1, 2]