On 10/17/07, Magnus Hagander <magnus@hagander.net> wrote:
> On Wed, Oct 17, 2007 at 02:40:14AM -0400, Tom Lane wrote:
> > Maybe we should put an #ifdef WIN32 into guc.c to limit max_connections
> > to something we know the platform can stand? It'd be more comfortable
> > if we understood exactly where the limit was, but I think I'd rather
> > have an "I'm sorry Dave, I can't do that" than random-seeming crashes.
>
> Yeayh, that's probably a good idea - except we never managed to figure out
> where the limit is. It appears to vary pretty wildly between different
> machines, for reasons we don't really know why (total RAM has some effect
> on it, but that's not the only one, for example)
I tried generating idle connections in an effort to reproduce
Laurent's problem, but I ran into a local limit instead: for each
backend, postmaster creates a thread and burns 4MB of its 2GB address
space. It fails around 490.
Laurent's issue must depend on other load characteristics. It's
possible to get a trace of DLL loads, but I haven't found a
noninvasive way of doing that. It seems to require a debugger be
attached.
