Re: IOWAIT

Hi Tshen,

Have you taken a peep at the execution plan and checked out for any unpredictable behaviour on Oracle's part ? Likely as not, the problem lies there.

Also check out v$session_event, v$session_wait and v$mystat to see if anything obvious pops out.

Cheers

Richard
"tshen" <tshen01_at_hotmail.com> wrote in message news:9Kjw9.988$S44.696_at_news4.srv.hcvlny.cv.net...
> hi,
>
> I have a SQL:
>
> select A.primary_access
> A.user_fname
> A.user_mname
> A.user_lname
> B.address
> B.zip
> C.phone
> C.pager
> from user A ,address B,person C
> where A.user_id=c.user_id
> and A.user_id= B.user_id
> A.valid_ind='Y'
> and A.dummy_ind='N'
> and copy_ind='N';
>
> summary:
> user 980000 rows.
> person 1230000 rows
> address 1560000 rows
>
> RDBMS: 8.1.7
> machine: sunfire
> 4 CPUs(900 MHZ)
> 4G memory (SGA 2G: shared pool 500M
> java pool 50M db buffer 1.6G)
>
> When I run this query, it takes a long time(over 1 min), when I use
> "top" it's shows
> IOWAIT 31%
> USER 25%
>
> How could it be????
> I run this query agaist a much slow machine with smaller SGA, slower
CPU.
> it only take about 4 seconds. so any suggestion?(hardware configuration?)
by
> the way, I create indexes for every involved columns. thanks.
>
> tshen
>
>
>
>
>
Received on Fri Nov 01 2002 - 06:11:46 CST