Re: count(*) performance

From: Gábriel Ákos <akos(dot)gabriel(at)i-logic(dot)hu>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: count(*) performance
Date: 2006-03-27 18:04:46
Message-ID: 4428293E.9080300@i-logic.hu
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Luke Lonergan wrote:

> To test your disk speed, use the following commands and report the times
> here:
>
> time bash -c "dd if=/dev/zero of=bigfile bs=8k count=500000 && sync"

root(at)panther:/fast # time bash -c "dd if=/dev/zero of=bigfile bs=8k
count=500000 && sync"
500000+0 records in
500000+0 records out
4096000000 bytes transferred in 45.469404 seconds (90082553 bytes/sec)
real 0m56.880s
user 0m0.112s
sys 0m18.937s

> time dd if=bigfile of=/dev/null bs=8k

root(at)panther:/fast # time dd if=bigfile of=/dev/null bs=8k
500000+0 records in
500000+0 records out
4096000000 bytes transferred in 53.542147 seconds (76500481 bytes/sec)

real 0m53.544s
user 0m0.048s
sys 0m10.637s

I guess these values aren't that bad :)

--
Üdvözlettel,
Gábriel Ákos
-=E-Mail :akos(dot)gabriel(at)i-logic(dot)hu|Web: http://www.i-logic.hu=-
-=Tel/fax:+3612367353 |Mobil:+36209278894 =-

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