Re: BUG #13643: Should a process dying bring postgresql down, or not?
От | Amir Rohan |
---|---|
Тема | Re: BUG #13643: Should a process dying bring postgresql down, or not? |
Дата | |
Msg-id | 5609B428.6020006@mail.com обсуждение исходный текст |
Ответ на | Re: BUG #13643: Should a process dying bring postgresql down, or not? (Alvaro Herrera <alvherre@2ndquadrant.com>) |
Ответы |
Re: BUG #13643: Should a process dying bring postgresql down,
or not?
(Alvaro Herrera <alvherre@2ndquadrant.com>)
|
Список | pgsql-bugs |
On 09/28/2015 12:06 AM, Alvaro Herrera wrote: > Amir Rohan wrote: >> On 09/27/2015 09:59 PM, Alvaro Herrera wrote: >>> amir.rohan@mail.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> <<<<<<<<<<<<<<< deadprocess >>>> 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] sendingbackup "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 ... > Pardon my earlier HTML response, I had to use the webmail interface at the time. Sending again as text. > > > Sent: Monday, September 28, 2015 at 12:06 AM > From: "Alvaro Herrera" <alvherre@2ndquadrant.com> > To: "Amir Rohan" <amir.rohan@mail.com> > Cc: pgsql-bugs@postgresql.org > Subject: 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.rohan@mail.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. > I *know*. But as you can see that backup process is already underway. That means pg_ctl had returned by then, and I had issued the pg_basebackup command. Since I didn't manually send a SIGSTOP, and postgres was already detached by then, I don't know how it could have gotten suspended. > Since pg_ctl is not normally long-lived, I'm not sure how you ended up > suspending it. > exactly. >> 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 ... > Well, It can teach you which electric socket will electrocute you when poked with a fork. That's useful data. Amir
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