From: Joshua D. Drake <jd@commandprompt.com>
To: mlunnon@rwa-net.co.uk
Cc: Sven Geisler <sgeisler@aeccom.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Limited performance on multi core server
Date: Wed, 12 Dec 2007 07:47:00 -0800
Message-ID: <47600274.40009@commandprompt.com> (raw)
In-Reply-To: <475FED09.2030102@rwa-net.co.uk>
References: <475FB50B.8060701@rwa-net.co.uk>
<475FCF1E.7030608@aeccom.com>
<475FED09.2030102@rwa-net.co.uk>
Matthew Lunnon wrote:
> Hi Sven,
>
> Does this mean that one option I have is to use a multi core Intel based
> server instead of an AMD based server?
Wow... hold on.
>> I remember that I also an issue with AMD Opterons before Pg 8.1
>> There is a specific Opteron behaviour on shared memory locks which adds
>> a extra "penalty" during the execution time for Pg code before 8.1.
I would like to see some proof of this.
>> I can you provide my patch for Pg 8.0 which should be adaptable for Pg
>> 7.4 if you can compile PostgreSQL.
>>
The real answer here is to upgrade to 8.1.10 or 8.2.5. 64bit if you can.
>>> I have a 4 * dual core 64bit AMD OPTERON server with 16G of RAM, running
>>> postgres 7.4.3. This has been recompiled on the server for 64 stored
>>> procedure parameters, (I assume this makes postgres 64 bit but are not
This type of machine, assuming you have decent IO available will
generally be very fast with anything >= 8.1.
>>> changes to postgresql.sql:
>>>
>>> max_connections = 500
>>> shared_buffers = 96000
Way to high for 7.4. Way to low for 8.1 or above (based on what you
mention your work load is)
>>> sort_mem = 10240
Based on your specs this actually may be fine but I would suggest
reviewing it after you upgrade.
>>> effective_cache_size = 1000000
>>>
Again, too low for 8.1 or above.
Sincerely,
Joshua D. Drake
--
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To: pgsql-performance@postgresql.org
Cc: jd@commandprompt.com, mlunnon@rwa-net.co.uk, sgeisler@aeccom.com
Subject: Re: Limited performance on multi core server
In-Reply-To: <47600274.40009@commandprompt.com>
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