On Tue, Mar 22, 2011 at 3:53 PM, Robert Haas <robertmh...@gmail.com> wrote:
> On Tue, Mar 22, 2011 at 11:24 AM, Jeff Janes <jeff.ja...@gmail.com> wrote: > > On Fri, Mar 18, 2011 at 9:19 AM, Robert Haas <robertmh...@gmail.com> > wrote: > >> On Fri, Mar 18, 2011 at 11:14 AM, Kevin Grittner > >> <kevin.gritt...@wicourts.gov> wrote: > >>> Maybe the thing to focus on first is the oft-discussed "benchmark > >>> farm" (similar to the "build farm"), with a good mix of loads, so > >>> that the impact of changes can be better tracked for multiple > >>> workloads on a variety of platforms and configurations. Without > >>> something like that it is very hard to justify the added complexity > >>> of an idea like this in terms of the performance benefit gained. > >> > >> A related area that could use some looking at is why performance tops > >> out at shared_buffers ~8GB and starts to fall thereafter. > > > > Under what circumstances does this happen? Can a simple pgbench -S > > with a large scaling factor elicit this behavior? > > To be honest, I'm mostly just reporting what I've heard Greg Smith say > on this topic. I don't have any machine with that kind of RAM. > I can sponsor a few hours (say 10) of one High-memory on-demand Quadruple Extra Large instance (26 EC2 Compute Units (8 virtual cores with 3.25 EC2 Compute Units each), 1690 GB of local instance storage, 64-bit platform). That's the largest memory AWS has. Let me know if I can help. Regards, -- Gurjeet Singh EnterpriseDB Corporation The Enterprise PostgreSQL Company
