silent_mode and LINUX_OOM_ADJ

Excerpts from Heikki Linnakangas's message of vie jun 24 07:01:57 -0400 2011:

While reviewing Peter Geoghegan's postmaster death patch, I noticed that
if you turn on silent_mode, the LINUX_OOM_ADJ code in fork_process()
runs when postmaster forks itself into background. That re-enables the
OOM killer in postmaster, if you've disabled it in the startup script by
adjusting /proc/self/oom_adj. That seems like a bug, albeit a pretty
minor one.

This may be a dumb question, but what is the purpose of silent_mode?
Can't you just use nohup?

I think silent_mode is an artifact from when our daemon handling in
general was a lot more primitive (I bet there wasn't even pg_ctl then).
Maybe we could discuss removing it altogether.

--
Álvaro Herrera <alvherre@commandprompt.com>
The PostgreSQL Company - Command Prompt, Inc.
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

On Fri, Jun 24, 2011 at 16:37, Alvaro Herrera
<alvherre@commandprompt.com> wrote:

Excerpts from Heikki Linnakangas's message of vie jun 24 07:01:57 -0400 2011:

While reviewing Peter Geoghegan's postmaster death patch, I noticed that
if you turn on silent_mode, the LINUX_OOM_ADJ code in fork_process()
runs when postmaster forks itself into background. That re-enables the
OOM killer in postmaster, if you've disabled it in the startup script by
adjusting /proc/self/oom_adj. That seems like a bug, albeit a pretty
minor one.

This may be a dumb question, but what is the purpose of silent_mode?
Can't you just use nohup?

I think silent_mode is an artifact from when our daemon handling in
general was a lot more primitive (I bet there wasn't even pg_ctl then).
Maybe we could discuss removing it altogether.

If I'm not entirely mistaken, it's on by default in SuSE RPMs. I don't
have a box with access right now, but I've come across it a couple of
times recently with clients, and I think that's how it is. Might want
to doublecheck with the suse maintainer if there's a particular reason
they do that...

--
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/

On 27.06.2011 10:23, Magnus Hagander wrote:

On Fri, Jun 24, 2011 at 16:37, Alvaro Herrera
<alvherre@commandprompt.com> wrote:

Excerpts from Heikki Linnakangas's message of vie jun 24 07:01:57 -0400 2011:

While reviewing Peter Geoghegan's postmaster death patch, I noticed that
if you turn on silent_mode, the LINUX_OOM_ADJ code in fork_process()
runs when postmaster forks itself into background. That re-enables the
OOM killer in postmaster, if you've disabled it in the startup script by
adjusting /proc/self/oom_adj. That seems like a bug, albeit a pretty
minor one.

This may be a dumb question, but what is the purpose of silent_mode?
Can't you just use nohup?

I think silent_mode is an artifact from when our daemon handling in
general was a lot more primitive (I bet there wasn't even pg_ctl then).
Maybe we could discuss removing it altogether.

If I'm not entirely mistaken, it's on by default in SuSE RPMs. I don't
have a box with access right now, but I've come across it a couple of
times recently with clients, and I think that's how it is. Might want
to doublecheck with the suse maintainer if there's a particular reason
they do that...

Yep, seems to be so. Max, you're the maintainer of the PostgreSQL SuSE
RPMs, right? Can you comment on the above?

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com

Hi Heikki,

On Mon, 27 Jun 2011 at 12:10, Heikki Linnakangas wrote:

Max, you're the maintainer of the PostgreSQL SuSE RPMs, right?

my first name is Reinhard, but aside from that, you are right. ;)

Can you comment on the above?

I enabled it many years ago when (IIRC) it was needed in conjunction
with "logging_collector = on" to get proper logging and especially log
rotation. It might very well be that it is not needed anymore and
suggestions for doing it better are welcome.

cu
Reinhard

--
SUSE LINUX Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer, HRB 16746 (AG Nürnberg)

On 27.06.2011 12:38, Reinhard Max wrote:

On Mon, 27 Jun 2011 at 12:10, Heikki Linnakangas wrote:

Max, you're the maintainer of the PostgreSQL SuSE RPMs, right?

my first name is Reinhard, but aside from that, you are right. ;)

Sorry :-)

Can you comment on the above?

I enabled it many years ago when (IIRC) it was needed in conjunction
with "logging_collector = on" to get proper logging and especially log
rotation. It might very well be that it is not needed anymore and
suggestions for doing it better are welcome.

It seems to me you could just stop setting silent_mode. If you want to
capture any early errors at startup into a log file, like silent_mode
does to postmaster.log, you can redirect stdout and stderr in the
startup script. pg_ctl start -l postmaster.log will do the same.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com

On Tue, 28 Jun 2011 at 10:40, Heikki Linnakangas wrote:

It seems to me you could just stop setting silent_mode. If you want
to capture any early errors at startup into a log file, like
silent_mode does to postmaster.log, you can redirect stdout and
stderr in the startup script. pg_ctl start -l postmaster.log will do
the same.

OK, thanks. I'll try that next time I touch the packages.

cu
Reinhard

--
SUSE LINUX Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer, HRB 16746 (AG Nürnberg)