Re: Immediate shutdown and system(3)

Hi,

On Mon, Mar 2, 2009 at 4:59 PM, Heikki Linnakangas
<heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
> Fujii Masao wrote:
>>
>> On Fri, Feb 27, 2009 at 6:52 PM, Heikki Linnakangas
>> <heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
>>>
>>> I'm leaning towards option 3, but I wonder if anyone sees a better
>>> solution.
>>
>> 4. Use the shared memory to tell the startup process about the shutdown
>> state.
>> When a shutdown signal arrives, postmaster sets the corresponding shutdown
>> state to the shared memory before signaling to the child processes. The
>> startup
>> process check the shutdown state whenever executing system(), and
>> determine
>> how to exit according to that state. This solution doesn't change any
>> existing
>> behavior of pg_standby. What is your opinion?
>
> That would only solve the problem for pg_standby. Other programs you might
> use as a restore_command or archive_command like "cp" or "rsync" would still
> core dump on the SIGQUIT.

Right. I've just understood your intention. I also agree with option 3 if nobody
complains about lack of backward compatibility of pg_standby. If no, how about
using SIGUSR2 instead of SIGINT for immediate shutdown of only the archiver
and the startup process. SIGUSR2 by default terminates the process.
The archiver already uses SIGUSR2 for pgarch_waken_stop, so we need to
reassign that function to another signal (SIGINT is suitable, I think).
This solution doesn't need signal multiplexing. Thought?

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center