Message-ID: <4C6D76FE.9010407@2ndquadrant.com>
Date: Thu, 19 Aug 2010 14:25:02 -0400
From: Greg Smith <greg@2ndquadrant.com>
User-Agent: Thunderbird 2.0.0.24 (X11/20100317)
MIME-Version: 1.0
To: Philippe Rimbault <primbault@edd.fr>
CC: pgsql-performance@postgresql.org
Subject: Re: Performance on new 64bit server compared to my 32bit
 desktop
References: <4C6CE64D.6070104@edd.fr>
In-Reply-To: <4C6CE64D.6070104@edd.fr>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

Philippe Rimbault wrote:
> I've run "time pgbench -c 50" :
>     server x64 :
>         starting vacuum...end.
>         transaction type: TPC-B (sort of)
>         scaling factor: 1
>         query mode: simple
>         number of clients: 50
>         number of transactions per client: 10
>         number of transactions actually processed: 500/500
>         tps = 523.034437 (including connections establishing)
>         tps = 663.511008 (excluding connections establishing)
>

As mentioned already, most of the difference you're seeing is simply 
that your desktop system has faster individual processor cores in it, so 
jobs where only a single core are being used are going to be faster on it.

The above isn't going to work very well either because the database 
scale is too small, and you're not running the test for very long.  The 
things the bigger server is better at, you're not testing.

Since your smaller system has 2GB of RAM and the larger one 32GB, try 
this instead:

pgbench -i -s 2000
pgbench -c 24 -T 60 -S
pgbench -c 24 -T 300

That will create a much larger database, run some simple SELECT-only 
tests on it, and then run a write intensive one.  Expect to see the 
server system crush the results of the desktop here.  Note that this 
will take quite a while to run--the pgbench initialization step in 
particular is going to take a good fraction of an hour or more, and then 
the actual tests will run for 6 minutes after that.  You can run more 
tests after that without doing the initialization step again, but if you 
run a lot of the write-heavy tests eventually performance will start to 
degrade.

-- 
Greg Smith  2ndQuadrant US  Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com   www.2ndQuadrant.us