MySQL Bugs: #102442: DROP DATABASE succeeds while the database directory on disk remains

Bug #102442	DROP DATABASE succeeds while the database directory on disk remains
Submitted:	1 Feb 2021 19:00	Modified:	2 Feb 2021 22:11
Reporter:	Peiran Song	Email Updates:
Status:	Can't repeat	Impact on me:	None
Category:	MySQL Server: DDL	Severity:	S3 (Non-critical)
Version:	8.0.18	OS:	Linux
Assigned to:		CPU Architecture:	Any

Description:
When the database directory's write permission is removed, the DROP DATABASE command would still succeed. The data dictionary is cleared, however the database directory on disk remains as is. 

In 5.6 and 5.7, the DROP DATABASE command would return an error on permission issue. 

How to repeat:
mysql> create database if not exists test;

shell: $sudo chmod -w <datadir>/test

mysql> drop database test;

shell: $ls -la <datadir>

Suggested fix:
DROP DATABASE should fail with permission error

Hello Peiran,

Thank you for the report and feedback.
I quickly tried to reproduce using latest GA 8.0.23 build but not seeing any issues i.e database directory on disk removed after drop database statement:

-
 bin/mysql -uroot -S /tmp/mysql_ushastry.sock
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 8.0.23 MySQL Community Server - GPL

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> create database if not exists test;
Query OK, 1 row affected (0.02 sec)

-- file system
ls -l 102442/test
total 0

-- shell terminal

chmod -w 102442/test/
ls -l 102442/test
total 0

-- mysql cli - drop database

mysql> drop database test;
Query OK, 0 rows affected (0.02 sec)

mysql>

-- shell terminal

ls -l 102442/test
ls: cannot access 102442/test: No such file or directory

Could you please confirm with 8.0.23 and report us back if you are still seeing the issue with server build details, OS? Thank you!

regards,
Umesh

Hi Umesh, 

Please try create a table in the database and try again. I missed on mentioning that. 

mysql> create database user;
mysql> use user;
mysql> create table users(a int) engine=innodb;
mysql> drop database user;
Query OK, 1 row affected, 1 warning (0.01 sec) 
mysql> show warnings;
Empty set (0.00 sec)

Btw, 'show warnings' didn't work either.