Re: scaling beyond 4 processors

In the last exciting episode, vogler(at)cipsoft(dot)com wrote:
> Hello everyone!
>
> Since our current Postgres server, a quad Xeon system, finally can't
> keep up with our load anymore we're ready to take the next step.
>
> So the question is: Has anyone experiences with running Postgres on
> systems with more than 4 processors in a production environment?
> Which systems and architectures are you using (e.g. IBM xseries, IBM
> pseries, HP Proliant, Sun Fire, 8- way Opteron)? How about conflicts
> between Postgres' shared memory approach and the NUMA architecture
> of most multi-processor machines?

The perhaps odd thing is that just about any alternative to quad-Xeon
is likely to be _way_ better. There are some context switching
problems that lead to it being remarkably poorer than you'd expect.
Throw in less-than ideal performance of the PAE memory addressing
system and it seems oddly crippled overall.

We've been getting pretty good results with IBM pSeries systems;
they're expensive, but definitely very fast.

Preliminary results with Opterons are also looking very promising.
One process seemed about 25x as fast on a 4-way 8GB Opteron as it was
on a 4-way 8GB Xeon, albeit with enough differences to make the
comparison dangerous.
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