Re: IOWAIT

Assuming that you have done a good job and compared the database situation on both machines (including objects, indexes, statistics, session settings, table sizes and data distribution), you may have contention in the buffer cache or on physical devices. Try to rule out devices first, load the associated disks with some work and run your query.

Regs
AK

tshen wrote:

> 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 Mon Nov 04 2002 - 01:05:25 CST