Обсуждение: BUG #17698: On SIGTERM, psql terminates, but leaves the statement running

The following bug has been logged on the website:

Bug reference:      17698
Logged by:          Dmitry Astapov
Email address:      dastapov@gmail.com
PostgreSQL version: 14.2
Operating system:   CentOS 7
Description:

Reproduction: start psql, launch a query that will take a while (I used
'select pg_sleep(1234)'), then from another terminal do "kill -TERM <pid of
psql>".
Psql would be terminated, but query would not be, and will keep running
until TCP timeout kicks in and kills the stale connection.

SIGINT, on the other hand, will cause psql will terminate the current
statement.

Perhaps psql could have a SIGTERM handler that does roughly what SIGINT
handler does before terminating the whole process, and would cancel the
current statement (if any)?

On 2022-Nov-25, PG Bug reporting form wrote:

> Reproduction: start psql, launch a query that will take a while (I
> used 'select pg_sleep(1234)'), then from another terminal do
> "kill -TERM <pid of psql>".  Psql would be terminated, but query would
> not be, and will keep running until TCP timeout kicks in and kills the
> stale connection.
> 
> SIGINT, on the other hand, will cause psql will terminate the current
> statement.
> 
> Perhaps psql could have a SIGTERM handler that does roughly what
> SIGINT handler does before terminating the whole process, and would
> cancel the current statement (if any)?

Sure.  I doubt we want to wait until a reply to the cancel request is
obtained, but we could have the sigterm handler at least send it before
terminating.

Why do you send SIGTERM to psql anyway?

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"Thou shalt not follow the NULL pointer, for chaos and madness await
thee at its end." (2nd Commandment for C programmers)

On Mon Jan 16, 2023 at 9:14 AM CST, Alvaro Herrera wrote:
> On 2022-Nov-25, PG Bug reporting form wrote:
>
> > Reproduction: start psql, launch a query that will take a while (I
> > used 'select pg_sleep(1234)'), then from another terminal do
> > "kill -TERM <pid of psql>".  Psql would be terminated, but query would
> > not be, and will keep running until TCP timeout kicks in and kills the
> > stale connection.
> >
> > SIGINT, on the other hand, will cause psql will terminate the current
> > statement.
> >
> > Perhaps psql could have a SIGTERM handler that does roughly what
> > SIGINT handler does before terminating the whole process, and would
> > cancel the current statement (if any)?
>
> Sure.  I doubt we want to wait until a reply to the cancel request is
> obtained, but we could have the sigterm handler at least send it before
> terminating.

I am currently working on a patch for this.

--
Tristan Partin
Neon (https://neon.tech)