Re: testing HS/SR - 1 vs 2 performance

On Mon, Apr 12, 2010 at 5:06 AM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
> On Sat, Apr 10, 2010 at 8:23 AM, Erik Rijkers <er(at)xs4all(dot)nl> wrote:
>> I understand that in the scale=1000 case, there is a huge
>> cache effect, but why doesn't that apply to the pgbench runs
>> against the standby?  (and for the scale=10_000 case the
>> differences are still rather large)
>
> I guess that this performance degradation happened because a number of
> buffer replacements caused UpdateMinRecoveryPoint() often. So I think
> increasing shared_buffers would improve the performance significantly.

I think we need to investigate this more. It's not going to look good
for the project if people find that a hot standby server runs two
orders of magnitude slower than the primary.

...Robert