From: Richard Huxton <dev@archonet.com>
To: H.J. Sanders <hjs@rmax.nl>
Cc: pgsql-performance@postgresql.org
Subject: Re: x206-x225
Date: Fri, 10 Mar 2006 13:40:22 +0000
Message-ID: <441181C6.3040401@archonet.com> (raw)
In-Reply-To: <GMEAJIDMNDKCIHMMHDFLCEKHDHAA.hjs@rmax.nl>
References: <GMEAJIDMNDKCIHMMHDFLCEKHDHAA.hjs@rmax.nl>
H.J. Sanders wrote:
> X206 IBM X226
> ---------------------- -------------------
> processor Pentium 4 3.2
> Ghz Xeon 3.0 Ghz
> main memory 1.25
> GB 4 GB
> discs 2 x SCSI RAID1 10000RPM
> 1 x ATA 7200 RPM
Noting that the SCSI discs are on the *slower* machine.
> Time at X206 Time at X226
> -------------------- ------------------
> insert record (1 to 10000) 6 sec. 41 sec.
> select record (1 to 10000) 4 4
> delete record (1 to 10000) 6 41
>
>
> This is ofcourse a totally unexpected results (you should think off the
> opposite).
Your ATA disk is lying about disk caching being turned off. Assuming
each insert is in a separate transaction, then it's not going to do
10,000 / 6 = 1667 transactions/sec - that's faster than it's rotational
speed.
> Funny is that the select time is the same for both machines.
Because you're limited by the speed to read from RAM.
By the way - these sort of tests are pretty much meaningless in any
practical terms.
--
Richard Huxton
Archonet Ltd
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To: pgsql-performance@postgresql.org
Cc: dev@archonet.com, hjs@rmax.nl
Subject: Re: x206-x225
In-Reply-To: <441181C6.3040401@archonet.com>
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