Re: Max shared_buffers

On Thu, Apr 3, 2008 at 11:16 AM, Andrej Ricnik-Bay
<andrej(dot)groups(at)gmail(dot)com> wrote:
> On 04/04/2008, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> wrote:
> > Not entirely true. on 32 bit OS / software, the limit is just under 2
> > Gig.
>
> Where do you get that figure from?
>
> There's an architectural (theoretical) limitation of RAM at 4GB,
> but with the PAE (that pretty much any CPU since the Pentium Pro
> offers) one can happily address 64GB on 32-bit.
>
> Or are you talking about some Postgres limitation?

Note I was talking about running 32 bit postgresql (on either 32 or 64
bit hardware, it doesn't matter) where the limit we've seen in the
perf group over the years has been just under 2G.

I'm extrapolating that on 64 bit hardware, 64 bit postgresql's limit
would be similar, i.e. 2^63-x where x is some small number that keeps
us just under 2^63.

So, experience and reading here for a few years is where I get that
number from. But feel free to test it. It'd be nice to know you
could get >2Gig shared buffer on 32 bit postgresql on some
environment.