Re: Postgresql and multithreading

This in many ways is a bogus argument in that 1) postgresql runs on more
then just Linux and 2) amount of memmory that can be addressed by a
process is tunable up to the point that it reaches a hardware limitation.

It also should be noted that when a process reaches such a size that it
better have a good reason. Now let us do a gedanken experiment and say
you do have a good reason - fork a couple of these and your machine will
thrash like nothing else ... also that whole hardware limitation will come
into play more sooner then later ...

On 21 Oct 2002, Doug McNaught wrote:

> "Steve Wolfe" <nw(at)codon(dot)com> writes:
>
> > On the recurring debate of threading vs. forking, I was giving it a fwe
> > thoughts a few days ago, particularly with concern to Linux's memory model.
> >
> > On IA32 platforms with over 4 gigs of memory, any one process can only
> > "see" up to 3 or 4 gigs of that. Having each postmaster fork off as a new
> > process obviously would allow a person to utilize very copious quantities of
> > memory, assuming that (a) they were dealing with concurrent PG sessions, and
> > (b) PG had reason to use the memory.
> >
> > I'm not entirely clear on threading in Linux - would it provide the same
> > benefits, or would it suddenly lock you into a 3-gig memory space?
>
> Linux threads are basically processes that share the same VM space, so
> you'd be limited to 3GB or whatever, since that's what a VM space can
> "see".
>
> -Doug
>
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