Re: count(*) performance - Mailing list pgsql-performance

From Gábriel Ákos
Subject Re: count(*) performance
Date
Msg-id 4428293E.9080300@i-logic.hu
Whole thread Raw
In response to Re: count(*) performance  ("Luke Lonergan" <llonergan@greenplum.com>)
List pgsql-performance
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@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@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.gabriel@i-logic.hu|Web:  http://www.i-logic.hu=-
-=Tel/fax:+3612367353            |Mobil:+36209278894            =-


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