References: <cone.1267562557.293175.32557.1000@shelca>
	<alpine.DEB.2.00.1003021313310.5131@asgard.lang.hm>
Message-ID: <cone.1267565781.443763.32557.1000@shelca>
From: Francisco Reyes <lists@stringsutils.com>
To: david@lang.hm
Cc: Pgsql performance <pgsql-performance@postgresql.org>
Subject: Re: 10K vs 15k rpm for analytics
Date: Tue, 02 Mar 2010 16:36:21 -0500
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david@lang.hm writes:

> With sequential scans you may be better off with the large SATA drives as 
> they fit more data per track and so give great sequential read rates.

I lean more towards SAS because of writes.
One common thing we do is create temp tables.. so a typical pass may be:
* sequential scan
* create temp table with subset
* do queries against subset+join to smaller tables.

I figure the concurrent read/write would be faster on SAS than on SATA. I am 
trying to move to having an external enclosure (we have several not in use 
or about to become free) so I could separate the read and the write of the 
temp tables.

Lastly, it is likely we are going to do horizontal partitioning (ie master 
all data in one machine, replicate and then change our code to read parts of 
data from different machine) and I think at that time the better drives will 
do better as we have more concurrent queries.