Re: Process wakeups when idle and power consumption

On 11.05.2011 13:34, Peter Geoghegan wrote:
> On 11 May 2011 09:54, Magnus Hagander<magnus(at)hagander(dot)net> wrote:
>
>> If you're doing this Win32 specific, take a look at
>> src/backend/port/win32/signal.c for an example.
>>
>> If you're not doing this win32-specific, I doubt we really want
>> threads to be involved...
>
> Well, that seems to be the traditional wisdom. It seems sensible to me
> that each process should look out for postmaster death itself though.
> Tom described potential race conditions in looking at ps output...do
> we really want to double the number of auxiliary processes in a single
> release of Postgres?

Uh, no you don't want any new processes on Unix. You want each process
to check for postmaster death every once in a while, like they do today.
The pipe-trick is to make sure the processes wake up promptly to notice
the death when the postmaster dies. You just need to add the
postmaster-pipe to the select() calls we already do.

I'm not sure if on Windows you can similarly just add to the
postmaster-pipe to the WaitForMultipleObjects() calls we already do.
Then you won't need new threads on Windows either.

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