Re: dropdb --force

On Thu, Sep 19, 2019 at 12:14 AM Pavel Stehule <pavel.stehule@gmail.com> wrote:
>
> Hi
>
> I am sending updated version - the changes against last patch are two. I use pg_terminate_backed for killing other terminates like Tom proposed. I am not sure if it is 100% practical - on second hand the necessary right to kill other sessions is  almost available - and consistency with pg_terminal_backend has sense. More - native implementation is significantly better then solution implemented outer. I fixed docs little bit - the timeout for logout (as reaction on SIGTERM is only 5 sec).
>
> Regards
>
> Pavel
>
>
I observed one thing with the latest patch:
There is a possibility that in case of drop database failure some
sessions may be terminated.

It can happen in the following scenario:
1) create database test; /* super user creates test database */
2) create user test password 'test@123'; /* super user creates test user */
3) alter user test nosuperuser; /* super user changes test use to non
super user */
4) alter database test owner to test; /* super user set test as test
database owner */

5) psql -d test /* connect to test database as super user - Session 1 */
6) psql -d postgres -U test /* connect to test database as test user -
Session 2 */
7) psql -d postgres -U test /* connect to test database as test user -
Session 3 */

8) drop database (force) test; /* Executed from Session 3 */

Drop database fails in Session 3 with:
ERROR:  must be a superuser to terminate superuser process

Session 2 is terminated, Session 1 is left as it is.

Is the above behaviour ok to terminate session 2 in case of drop
database failure?
Thoughts?

Regards,
Vignesh
EnterpriseDB: http://www.enterprisedb.com