| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
 |
 | |||
| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
|
| |||
Home -> Community -> Usenet -> c.d.o.misc -> Re: tablescans vs indexed scan
SC wrote:
>
> Hello,
>
> Our database is going very slow (Oracle 7.3.3.6, Open VMS-7.1)
> and we discovered that many queries are performing tablescans
> rather than indexed scans. This is increasing
> Input/Output drastically and hence the database is very slow.
>
> Could anyone please advise me how can I make the query to
> use indexes? I am sure that the indexes exist as we have
> always been using them. So why the performance is going
> down NOW ? Will rebuilding indexes be any help?
> Also how can i detect which indexes are used and
> which ones arent?
>
> Please Help. (please send me an email at s_c_99_at_hotmail.com
> as well)
>
> Thanks.
>
> SC.
Check the statistics on the tables and the optimizer mode..
CHOOSE leans towards full scans
FIRST_ROWS will lean toward index use
You could always go back to rule mode but this is probably not the best option.
HTH
--
"Some days you're the pigeon, and some days you're the statue." Received on Thu Jan 20 2000 - 05:23:14 CST
 |
 |