Session can access a table that has not been locked in this session.

[CbcWestwolf]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

unlock tables;
drop table if exists t, s;
create table t (c int);
create table s (c int);
insert into s values (1),(2),(3);
insert into t values (1),(2),(3);
lock table t read;
select * from s;

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

tidb > select * from s;
ERROR 1100 (HY000): Table 's' was not locked with LOCK TABLES

3. What did you see instead (Required)

tidb> select * from s;
+------+
| c    |
+------+
|    1 |
|    2 |
|    3 |
+------+
3 rows in set (0.00 sec)

4. What is your TiDB version? (Required)

tidb_version(): Release Version: v5.4.0-alpha-652-g84e051834-dirty
Edition: Community
Git Commit Hash: 84e0518344d9826588db3644fee9065a9e729fef
Git Branch: master
UTC Build Time: 2022-01-09 12:14:35
GoVersion: go1.16
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false

[djshow832]

Is it the same with #28967?

[CbcWestwolf]

Is it the same with #28967?

Not exactly. This issue refers to one session, while the issue you mentioned refers to two sessions.

[bb7133]

I don't think it's a major bug: the table lock is a 'hidden' feature(it is closed by default and not documented). I will mark it as 'minor' bug.

[CbcWestwolf]

/assign