RE: consistency in cost?

Forgive my ignorance but I thought hints were only for cost based optimizer.

Have you checked in case anybody has changed any parameters while the system is running as I know that changing the hash_area_size can change the execution plan?. Are you using parallelism as if a table had to be recreated for any reason and its degree changed it might do a FTS?

Cheers

Iain Nicoll

-----Original Message-----
Sent: 08 May 2001 17:31
To: Multiple recipients of list ORACLE-L

Jared,
The only difference is about a weeks worth of extra data. Well, the hardware is also different (Ultra450 vs. Ultra 5000. Also 1 vs 4 CPU). But regardless, shouldn't init.ora optimizer_mode=choose be identical to optimizer_mode=rule with hint=choose? If I have the time, I'll try to set up a couple of systems and examine by moving stats and taking some 10053 dumps. (one of the ones giving me a problem is in production so I have limited play time there).

Henry

-----Original Message-----
Sent: Tuesday, May 08, 2001 12:56 AM
To: ORACLE-L_at_fatcity.com; Henry Poras

Henry,

You say 'nearly identical'.

What are the differences?

Are the 2 databases on the same platform?

If not, what are the differences, hardware and OS?

Jared

On Monday 07 May 2001 21:55, Henry Poras wrote:
> I am working with an 8.1.6 database on Solaris 2.6 and I am wondering if
> there is any consistency in the optimizer. We have two nearly identical
> databases (one a clone from two weeks ago). A five table join has nearly
> the identical execution plan on the two databases. The difference is in
the
> access method of the fourth table in the join; in one case it is accessed
> by a FTS and in the other, by Index. This difference has a large effect on
> performance. Statistics are nearly identical for this table in both
> databases (I looked at dba_tables, dba_indexes, dba_col_tables). Also, the
> init.ora is the same. When I changed the optimizer_mode to rule and added
a
> 'choose' hint to the query, the execution plan was different again. I will
> look into this a bit further and post my results. Just wondering about
> other's experiences. Thanks.
>
> Henry

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Henry Poras
  INET: Henry.Poras_at_ctp.com

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).
-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Nicoll, Iain (Calanais)
  INET: iain.nicoll_at_calanais.com

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).