Message-ID: <46027F65.9080909@bandwidth.com>
Date: Thu, 22 Mar 2007 09:06:45 -0400
From: David Brain <dbrain@bandwidth.com>
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To: Bill Moran <wmoran@collaborativefusion.com>
CC: pgsql-performance@postgresql.org
Subject: Re: Potential memory usage issue
References: <460271B9.8050600@bandwidth.com>
	<20070322085037.54780906.wmoran@collaborativefusion.com>
In-Reply-To: <20070322085037.54780906.wmoran@collaborativefusion.com>
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Hi,

Thanks for the response.
Bill Moran wrote:
> In response to David Brain <dbrain@bandwidth.com>:
>> I recently migrated one of our large (multi-hundred GB) dbs from an 
>> Intel 32bit platform (Dell 1650 - running 8.1.3) to a 64bit platform 
>> (Dell 1950 - running 8.1.5).  However I am not seeing the performance 
>> gains I would expect
> 
> What were you expecting?  It's possible that your expectations are
> unreasonable.
> 

Possibly - but there is a fair step up hardware performance wise from a 
1650 (Dual 1.4 Ghz PIII with U160 SCSI) to a 1950 (Dual, Dual Core 2.3 
Ghz Xeons with SAS) - so I wasn't necessarily expecting much from the 
32->64 transition (except maybe the option to go > 4GB easily - although 
currently we only have 4GB in the box), but was from the hardware 
standpoint.

I am curious as to why 'top' gives such different output on the two 
systems - the datasets are large and so I know I benefit from having 
high shared_buffers and effective_cache_size settings.

> Provide more information, for one thing.  I'm assuming from the top output
> that this is some version of Linux, but more details on that are liable
> to elicit more helpful feedback.
> 
Yes the OS is Linux - on the 1650 version 2.6.14, on the 1950 version 2.6.18

Thanks,

David.


-- 
David Brain - bandwidth.com
dbrain@bandwidth.com
919.297.1078