Re: Processor speed relative to postgres transactions per second - Mailing list pgsql-general

From Merlin Moncure
Subject Re: Processor speed relative to postgres transactions per second
Date
Msg-id b42b73151003300722p6cc13d89lf10a80c462a2a366@mail.gmail.com
Whole thread Raw
In response to Processor speed relative to postgres transactions per second  (Chris Barnes <compuguruchrisbarnes@hotmail.com>)
List pgsql-general
On Mon, Mar 29, 2010 at 12:42 PM, Chris Barnes
<compuguruchrisbarnes@hotmail.com> wrote:
>
> We have two camps that think that the speed of cpu processors is/aren't
> relative to the number of transactions that postgres that can performed per
> second.
>
> I am of the opinion that is we throw the faster processors at the database
> machine, there will be better performance.

which tastes better, a round fruit or a oval fruit? :-).

postgres can become i/o bound or cpu bound depending on the
application, or specific things you are doing.  if your application is
highly latency sensitive, then more cpu power is always nice.

cpu and i/o have completely different cost/performance scaling metrics:
cpu is very cheap to scale up to a point (when you hit limits of x86
at current levels) then becomes extremely expensive.  cpu bound
problems tend to degrade relatively well when your limit is hit.

i/o is expensive to scale but has relatively linear relationship
between cost and performance.  i/o bottleneck can bring your server to
a crawl, and sometimes comes out of nowhere when you nudge the work
the db has to do just a hair exceeding your system's ability to cope.

merlin

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