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Re: Hardware/OS recommendations for large databases (

From: Mark Kirkwood <markir(at)paradise(dot)net(dot)nz>
To: Luke Lonergan <llonergan(at)greenplum(dot)com>
Cc: stange(at)rentec(dot)com, Greg Stark <gsstark(at)mit(dot)edu>, Dave Cramer <pg(at)fastcrypt(dot)com>, Joshua Marsh <icub3d(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Hardware/OS recommendations for large databases (
Date: 2005-11-22 05:10:24
Message-ID: 4382A840.3030401@paradise.net.nz (view raw or flat)
Thread:
Lists: pgsql-performance
Luke Lonergan wrote:

> So that leaves the question - why not more than 64% of the I/O scan rate?
> And why is it a flat 64% as the I/O subsystem increases in speed from
> 333-400MB/s?
> 

It might be interesting to see what effect reducing the cpu consumption 
  entailed by the count aggregation has - by (say) writing a little bit 
of code to heap scan the desired relation (sample attached).

Cheers

Mark





Attachment: fastcount.c
Description: text/plain (978 bytes)

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