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@commandprompt.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.