From: Joshua D. Drake <jd@commandprompt.com>
To: Mark Wong <markw@osdl.org>
Cc: Luke Lonergan <llonergan@greenplum.com>
Cc: Patrick Welche <prlw1@newn.cam.ac.uk>
Cc: pgsql-performance@postgresql.org
Cc: maryedie@osdl.org
Subject: Re: [PATCHES] COPY FROM performance improvements
Date: Thu, 28 Jul 2005 16:57:24 -0700
Message-ID: <42E970E4.4010902@commandprompt.com> (raw)
In-Reply-To: <200507282343.j6SNhEjA013300@smtp.osdl.org>
References: <42E128BD.2000104@commandprompt.com>
<BF0696FB.9795%llonergan@greenplum.com>
<200507282343.j6SNhEjA013300@smtp.osdl.org>
>>
>>>[root@pq-slave root]# /sbin/hdparm -tT /dev/sda
>>>
>>>/dev/sda:
>>> Timing buffer-cache reads: 1816 MB in 2.00 seconds = 908.00 MB/sec
>>> Timing buffered disk reads: 26 MB in 3.11 seconds = 8.36 MB/sec
>>>[root@pq-slave root]#
>>
>>Can you post the "time dd if=/dev/zero of=bigfile bs=8k count=500000"
>>results? Also do the reverse (read the file) with "time dd if=bigfile
>>of=/dev/null bs=8k".
I didn't see this come across before... here ya go:
time dd if=/dev/zero of=bigfile bs=8k count=500000
500000+0 records in
500000+0 records out
real 1m52.738s
user 0m0.310s
sys 0m36.590s
time dd if=bigfile of=/dev/null bs=8k
time dd if=bigfile of=/dev/null bs=8k
500000+0 records in
500000+0 records out
real 4m38.742s
user 0m0.320s
sys 0m27.870s
FYI on your hardware raid comment... I easily get 50 megs a second on my
3ware controllers and faster on my LSI SATA controllers.
Sincerely,
Joshua D. Drake
>
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To: pgsql-performance@postgresql.org
Cc: jd@commandprompt.com, markw@osdl.org, llonergan@greenplum.com, prlw1@newn.cam.ac.uk, maryedie@osdl.org
Subject: Re: [PATCHES] COPY FROM performance improvements
In-Reply-To: <42E970E4.4010902@commandprompt.com>
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