Re: BUG #13643: Should a process dying bring postgresql down, or not?

Amir Rohan wrote:
> On 09/27/2015 09:59 PM, Alvaro Herrera wrote:
> > amir(dot)rohan(at)mail(dot)com wrote:
> >
> >> postgres 2181 0.0 0.1 134468 9504 pts/0 T 03:34 0:00 /usr/local/pgsql/bin/postgres -D /home/local/pg/s1
> >> postgres 2183 0.0 0.0 134576 4168 ? Ss 03:34 0:00 postgres: checkpointer process
> >> postgres 2184 0.0 0.0 134604 2844 ? Ss 03:34 0:00 postgres: writer process
> >> postgres 2185 0.0 0.0 134468 2780 ? Ss 03:34 0:00 postgres: wal writer process
> >> postgres 2186 0.0 0.0 0 0 ? Zs 03:34 0:00 [postgres] <defunct> <<<<<<<<<<<<<<< dead process
> >> postgres 2187 0.0 0.0 127300 2204 ? Ss 03:34 0:00 postgres: stats collector process
> >> postgres 2193 0.0 0.0 118164 2696 pts/0 T 03:34 0:00 pg_basebackup -D /home/local/pg/backup -p 57833 --format=t -x
> >> postgres 2194 0.0 0.0 134916 6016 ? Ss 03:34 0:00 postgres: wal sender process user1 [local] sending backup "pg_basebackup base backup"
> >
> > That postmaster is in STOPped mode is the issue here. That doesn't
> > happen unless you take specific action to do that.
>
> I hadn't noticed that. That looks like I suspended pg_ctl during start,
> but with the backup in progress already, it's not clear how I managed
> that state. There was no kill -SIGSTOP involved...

Suspending a process *is* sending sigstop. You may not have sent
sigstop explicitely, but the shell would have done it if you suspended
the process.

Since pg_ctl is not normally long-lived, I'm not sure how you ended up
suspending it.

> After killing some subprocesses in random I do see postgres
> restarting the whole group once one goes down, if/once its
> running/unsuspended.

Well, doing things randomly is unlikely to teach you much ...

--
Álvaro Herrera http://www.2ndQuadrant.com/
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