RE: Optimizing a query

Thanks John!
This is a custom code and I am testing it with the hint as this is something that we can control easily.

-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]
Sent: Monday, April 03, 2006 8:25 PM
To: Hameed, Amir; Mladen Gogala
Cc: oracle-l_at_freelists.org
Subject: RE: Optimizing a query

Amir,

I see that this is on an APPS database. Be careful while turning on PQO. The WSH tables can be accessed by a _lot_ of users simultaneously, and assigning a DOP on the table might result in PQ slaves starting up for all queries on that table. If you are tuning a custom report, then of course you can use the parallel hint.

I remember the early days of 11i when some 'duh'leveloper_at_Oracle assign a DOP of 20 to a large table in the hope of making it 'run faster' - it killed our (at that time) 8 CPU machine until we drastically scaled down PARALLEL_MAX_SLAVES . Sun was very happy to sell us a 24 CPU box just for that query!

John

-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Hameed, Amir Sent: Monday, April 03, 2006 4:48 PM
To: Mladen Gogala
Cc: oracle-l_at_freelists.org
Subject: RE: Optimizing a query

Thanks Mladen! The production server does have 40 CPUs. I am looking at the optimization from the RAC standpoint. Would PQO-based FTS be better than regular (buffer-based) FTS in RAC?

-----Original Message-----
From: Mladen Gogala [mailto:gogala_at_sbcglobal.net] Sent: Monday, April 03, 2006 7:01 PM
To: Hameed, Amir
Cc: oracle-l_at_freelists.org
Subject: Re: Optimizing a query

Amir, you don't have any limiting condition. Table apps.WSH_DELIVERY_ASSIGNMENT, according to your query, must be read in its entirety. The most efficient way to do so is the full table scan. Yu can try with /*+ parallel */ if the hardware is such that you can do that.

On 04/03/2006 05:21:46 PM, Hameed, Amir wrote:
> Folks,
> I need to optimize the following query:
>
> SELECT DELIVERY_DETAIL_ID,DELIVERY_ID
> FROM
> ( SELECT MIN(DELIVERY_DETAIL_ID) OVER (PARTITION BY DELIVERY_ID)
> MIN_DELIVERY_DET_ID,
> DELIVERY_DETAIL_ID,DELIVERY_I
> FROM apps.WSH_DELIVERY_ASSIGNMENTS
> )
> WHERE MIN_DELIVERY_DET_ID = DELIVERY_DETAIL_ID /
>
> This table has the following indices:
>
> COL DISTINCT
> INDEX NAME COLUMN NAME POS ROWS
> SELECTIVITY
> ------------------------------ ------------------------- ---
> -----------
> -------
> WSH_DELIVERY_ASSIGNMENTS_N1 DELIVERY_ID 1
630,301
> 8.29
> WSH_DELIVERY_ASSIGNMENTS_N2 PARENT_DELIVERY_ID 1
0
> 0.00
> WSH_DELIVERY_ASSIGNMENTS_N3 DELIVERY_DETAIL_ID 1
7,605,650
> 100.00
> WSH_DELIVERY_ASSIGNMENTS_N4 PARENT_DELIVERY_DETAIL_ID 1
377,456
> 4.96
> WSH_DELIVERY_ASSIGNMENTS_U1 DELIVERY_ASSIGNMENT_ID 1
7,605,650
> 100.00
>
> What would be the best way to optimize it. It currently does a FTS on
> this table. Any help will be appreciated.
> Thanks
> Amir
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

--
Mladen Gogala
http://www.mgogala.com

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