Re: BUG #15076: postmaster crashes unexpectedly when using up arrow key in psql command

On Thu, Feb 22, 2018 at 4:12 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> =?UTF-8?B?6LaZ5piO5pil?= <mzhao(at)insight-tec(dot)co(dot)jp> writes:
> > So, Let me change my question:
> > If I started the PostgreSQL by pg_ctl command in the same Windows command
> > prompt,
> > Is it possible that pressing Ctrl + C on psql to break query(not session)
> > will send SIGINT to postmaster process unexpectedly?
>
> I don't know much about Windows signal processing, but the log entries you
> show certainly look like that's what happened.
>

Yes, this is unfortunately exactly how it works on Windows.

There is on way to intercept the Ctrl-C and have it not delivered to *all*
processes out of the same session. It can only be added or removed for the
current process (which psql does). So it gets delivered to the backends
which call pg_console_handler, which emulates SIGINT.

On Unix-ish machines it's normal for control-C to send a SIGINT to every
> process that's in the terminal's process group --- *not* just the
> foreground process. So if you launch the postmaster manually you'd better
> make sure that it gets dissociated from the terminal, or you're at risk
> of killing it accidentally. (Or, if you want to leave it connected to
> that terminal, you use another window to run psql etc.) It seems that
> something similar is happening on your Windows setup. I don't know
> the rules for process/terminal association on Windows, so I can't suggest
> what's the right way to do it. I will say though that most people
> run the postmaster as a background service on Windows, rather than
> launching it manually.
>

AFAIC Windows has no way to disassociate a process with a console window in
a similar way.

--
Magnus Hagander
Me: https://www.hagander.net/ <http://www.hagander.net/>
Work: https://www.redpill-linpro.com/ <http://www.redpill-linpro.com/>