Re: [GENERAL] Shutting down a warm standby database in 8.2beta3

Stephen Harris <lists(at)spuddy(dot)org> writes:
> On Fri, Nov 17, 2006 at 10:49:39PM -0500, Tom Lane wrote:
>> This does not apply to signals originated by the postmaster --- it
>> doesn't even know that the child process is doing a system(), much less
>> have any way to signal the grandchild. Ugh.

> Why not, after calling fork() create a new process group with setsid() and
> then instead of killing the recovery thread, kill the whole process group
> (-PID rather than PID)? Then every process (the recovery thread, the
> system, the script, any child of the script) will all receive the signal.

This seems like a good answer if setsid and/or setpgrp are universally
available. I fear it won't work on Windows though :-(. Also, each
backend would become its own process group leader --- does anyone know
if adding hundreds of process groups would slow down any popular
kernels?

[ thinks for a bit... ] Another issue is that there'd be a race
condition during backend start: if the postmaster tries to kill -PID
before the backend has managed to execute setsid, it wouldn't work.

regards, tom lane