Andrew Sullivan <andrew@libertyrms.info> writes:
> I think the "25%" rule of thumb is slightly stale: above some
> threshold, it just falls apart, and lots of people now have machines
> well within that threshold. Heck, I'll bet Bruce's 2-way machine is
> within that threshold.
IIRC, we've not seen much evidence that increasing shared_buffers above
about 10000 delivers any performance boost. That's 80Mb, so the "25%"
rule doesn't get seriously out of whack until you get to a gig or so of
RAM. Which was definitely not common at the time the rule was put
forward, but is now. Probably we should modify the rule-of-thumb to
something like "25%, but not more than 10000 buffers".
regards, tom lane