Stale read failed for read-committed isolation when autocommit=0

[lcwangchao]

Bug Report

Stale read failed for read-committed isolation

1. Minimal reproduce step (Required)

drop table if exists t1;
create table t1(id int primary key);
set tx_isolation = 'READ-COMMITTED';
set autocommit=0;
select * from t1 as of timestamp now() where id=1;

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

mysql> select * from t1 as of timestamp now() where id=1;
Empty set (0.00 sec)

3. What did you see instead (Required)

mysql> select * from t1 as of timestamp now() where id=1;
ERROR 8024 (HY000): invalid transaction

4. What is your TiDB version? (Required)

master

[zyguan]

Hi, @lcwangchao , which commit do you use? I only got some E1146: Table 'test.t1' doesn't exist occasionally with latest master (55a38cb).

[lcwangchao]

@zyguan sorry, the previous description is not right and I just modified it. This error occurs when read-committed and autocommit=0 .

[zyguan]

It seems ts future won't be prepared since #29393 , tidb tried to active transaction for the point select statement (as the following stack shown), and then invalid transaction got returned here. @Yisaer could you take a look?

github.com/pingcap/tidb/executor.(*executorBuilder).getSnapshotTS
        /home/zyguan/src/pingcap/tidb/executor/builder.go:1502
github.com/pingcap/tidb/executor.(*executorBuilder).buildPointGet
        /home/zyguan/src/pingcap/tidb/executor/point_get.go:51