Re: I/O performance problem

Giuseppe,

I think your problem is your doing 43285 reads and 24,000 odd disk accesses in order to return 6 rows. This is about 4,000 disk accesses per row returned! The SQL statement may be a little inefficient.

If you post the SQL some of our tuning stars can probably help you.

Dave O'Keeffe

Giuseppe De Donno wrote:
>
> I think to have a degrade of performance in I/O system.
> By SQL TRACE I have the follow report:
>
> call count cpu elapsed disk query
> current rows
> ------- ------ -------- ---------- ---------- ---------- ----------
> ----------
> Parse 1 0.01 0.00 0 0
> 0 0
> Execute 1 0.02 0.00 0 0
> 0 0
> Fetch 1 23.74 42.61 24348 43285
> 6 6
> ------- ------ -------- ---------- ---------- ---------- ----------
> ----------
> total 3 23.77 42.61 24348 43285
> 6 6
>
> Misses in library cache during parse: 0
> Optimizer goal: CHOOSE
>
> The fetch is of ~24 seconds!!!
> Is it a problem of I/O system?
>
> How do i do?
>
> Thank
> Giuseppe

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