Re: Postmaster can't stop with pg_ctl

Thank you for your reply.

On Wed, 25 Apr 2007 09:44:47 -0400
Alvaro Herrera <alvherre(at)commandprompt(dot)com> wrote:

> takuya koide wrote:
>
> > 4) send 'SIGSTOP' signal to postgres
> > # kill -SIGSTOP 3619
> > # ps axuw|grep -i postgres|grep -Ev 'grep|bash|su -'
> > postgres 3507 0.0 1.1 21352 2804 ? S 18:48 0:00
> > /usr/bin/postmaster -p 5432 -D /var/lib/pgsql/data
> > postgres 3509 0.0 0.2 11132 568 ? S 18:48 0:00 postgres: logger process
> > postgres 3514 0.0 0.3 21352 852 ? S 18:48 0:00 postgres: writer process
> > postgres 3515 0.0 0.2 12132 564 ? S 18:48 0:00 postgres: stats buffer process
> > postgres 3516 0.0 0.3 11364 772 ? S 18:48 0:00 postgres: stats collector process
> > postgres 3618 0.0 0.6 8476 1752 pts/3 S+ 18:54 0:00 psql template1
> > postgres 3619 0.0 0.8 22012 2124 ? T 18:54 0:00 postgres:
> > postgres template1 [local] idle
>
> If you "stop" a process by SIGSTOP you must make it run again with
> SIGCONT. Otherwise it's just not processing signals, so it'll obviously
> not shut down. I don't think this is a bug.

I am sorry lack of my talk about SIGSTOP.

[assumed premise]
I have performed PostgreSQL with third-party cluster system and have evaluated
that if PostgreSQL's status become unusual, cluster system can stop PostgreSQL.
So I have used SIGSTOP to create environment like this case.

[result]
This cluster system picked up stalled postgres process and tried to stop
PostgreSQL with /etc/rc.d/init.d/postgresql. but pg_ctl colud not stop it.
(I confirmed that cluster system perform /etc/rc.d/init.d/postgresql)

[expectation]
I expect that pg_ctl can stop PostgreSQL even if postgres processes
or postgres process stalled.

Thank you.
Best Regards
---
Takuya Koide
NEC System Technologies, Ltd.