Re: testing HS/SR - 1 vs 2 performance - Mailing list pgsql-hackers

From Robert Haas
Subject Re: testing HS/SR - 1 vs 2 performance
Date
Msg-id v2o603c8f071004120407maf4459c4o7404dd2bd94a7401@mail.gmail.com
Whole thread Raw
In response to Re: testing HS/SR - 1 vs 2 performance  (Fujii Masao <masao.fujii@gmail.com>)
Responses Re: testing HS/SR - 1 vs 2 performance  (Jim Mlodgenski <jimmy76@gmail.com>)
Re: testing HS/SR - 1 vs 2 performance  (Aidan Van Dyk <aidan@highrise.ca>)
List pgsql-hackers
On Mon, Apr 12, 2010 at 5:06 AM, Fujii Masao <masao.fujii@gmail.com> wrote:
> On Sat, Apr 10, 2010 at 8:23 AM, Erik Rijkers <er@xs4all.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


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