Re: BUG #16145: Not able to terminate active session

On Tue, Dec 03, 2019 at 01:18:50PM +0000, PG Bug reporting form wrote:
>The following bug has been logged on the website:
>
>Bug reference:      16145
>Logged by:          MOHAN KUMAR DORAIRAJ
>Email address:      [email protected]
>PostgreSQL version: 11.2
>Operating system:   Red Hat Enterprise Linux Server release 7.6 (Maipo
>Description:
>
>Not able to terminate active session even though used below commands
>
>postgres=# SELECT pg_cancel_backend(16647);
> pg_cancel_backend
>-------------------
> t
>(1 row)
>
>postgres=# SELECT pg_terminate_backend(16647);
> pg_terminate_backend
>----------------------
> t
>(1 row)
>
>postgres=#  select pid,application_name FROM pg_stat_activity where
>application_name IS  NOT NULL AND state = 'active';
>  pid  |    application_name
>-------+------------------------
> 16647 | PostgreSQL JDBC Driver
> 19879 | psql
>

So what is happening in 16647? What query is it running? Can you attach
gdb to it and show us the backtrace?

It's probably running some CPU-intensive piece of code, not checking the
flags set by signal handlers, or something like that.

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services