Re: Backend process is still runs even postmaster got killed

>On Fri, Dec 7, 2012 at 7:26 PM, Thalis Kalfigkopoulos
<tkalfigo(at)gmail(dot)com> wrote:

>>On Fri, Dec 7, 2012 at 10:21 AM, Hari Babu <
<mailto:haribabu(dot)kommi(at)huawei(dot)com> haribabu(dot)komm(at)huawei(dot)com>
wrote:

>>Backend processes are still running even if the postmaster got killed and
all other server processes are exited by checking the

>>Postmaster status.

>>And the backend process is providing the service to the client.

>>Is there any problems are possible? If we continue the system for a long
time with the above behavior?

>>Until all these kind of backend processes are exited, postmaster is
failing to start.

>>Manual cleanup is required for these backend processes? Or is there anyway
we can handle?

>Hi Hari.

>

>How exactly do you kill the postmaster? It is suggested you use pg_ctl for
server shutdowns/restarts. Check out the option -m:
>-m SHUTDOWN-MODE can be "smart", "fast", or "immediate"
>Shutdown modes are:
> smart quit after all clients have disconnected
> fast quit directly, with proper shutdown
> immediate quit without complete shutdown; will lead to recovery on
restart

>"Smart" will wait for all your backend processes to terminate (or fail if
it takes too long). If i remember correctly "fast" will cause the postmaster
to exit even if >backends are still up, the equivalent of sending a kill -15
(SIGTERM). And "immediate" is like sending a kill -9 (SIGKILL) i.e. violent
shutdown of everything.
>
>I'm guessing you went for the equivalent of SIGTERM that's why you still
have backends running.

Usually we are using the pg_ctl with shutdown option only.

Actually I thought of asking the postmaster crash scenario, which I have
simulated with kill -9 PID.

I know postmaster crash is a very rare scenario, In this I want to know what
are all the problems can occur?

Regards,

Hari babu.