> -----Original Message-----
> From: mlw [mailto:markw@mohawksoft.com]
> Sent: Tuesday, May 07, 2002 7:58 AM
> To: Marc G. Fournier
> Cc: Tom Lane; PostgreSQL-development
> Subject: Re: [HACKERS] OK, lets talk portability.
>
>
> "Marc G. Fournier" wrote:
> >
> > On Tue, 7 May 2002, mlw wrote:
> >
> > > Tom Lane wrote:
> > > > And no, I don't want to undo those changes. Especially
> not if the
> > > > only reason for it is to not have to use Cygwin on
> Windows. Most
> > > > of these changes made the startup code substantially simpler,
> > > > faster, and more reliable.
> > >
> > > Then I think the notion of a pure Windows version is dead
> in the water.
> > > Writing a fork()-like API for Windows is, of course,
> doable as evidenced
> > > by cygwin, and from a general theory seems like a pretty straight
> > > forward thing to do (with a few low level tricks of
> course) but the
> > > details are pretty scary.
> >
> > How is Apache doing this? I believe they do allow the
> pre-forked model to
> > work, so how are they getting around those limitations?
>
> Apache and PostgreSQL are quite different in their
> requirements of shared
> memory. Apache (2.x) simply uses CreateProcess and passes
> duplicate file
> handles.
The way to make CreateProcess() work for PostgreSQL is very simple.
By the time of the fork(), not much has been done. Some needed
calculations can simply be stored into shared memory (which is trivial
to implement). Some other tasks can simply be executed by the cloned
process, exactly as they were executed in the server.
Using fork() on Win32 is pointless, hopless, awful. Don't even think
about it. It's a death warrant.