RE: Composite Index Order VS Query Order ?? , Tuning Docs URL ?.

From: "Cary Millsap" <cary.millsap@xxxxxxxxxx>
To: <oracle-l@xxxxxxxxxxxxx>, <"undisclosed-recipients:"@www.hotsos.com>
Date: Tue, 13 Jul 2004 10:40:50 -0500

1. No. The order of keys in a composite index does NOT need to be in the
same order as the ANDed predicates in your WHERE clause. Now, if you =
have an
ORDER BY clause, it will speed your query if the columns there and the
composite index columns are listed in the same order (because it will =
save a
sort operation).

2. Check Dan Tow's "Tuning SQL" book, published by O'Reilly and =
Associates.


Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
* Nullius in verba *

Upcoming events:
- Performance Diagnosis 101: 7/20 Cleveland, 8/10 Boston, 9/14 San =
Francisco
- SQL Optimization 101: 7/26 Washington DC, 8/16 Minneapolis, 9/20 =
Hartford
- Hotsos Symposium 2005: March 6-10 Dallas
- Visit www.hotsos.com for schedule details...


-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx =
[mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of Ranjeesh K R.
Sent: Tuesday, July 13, 2004 9:54 AM
To: undisclosed-recipients:
Subject: Composite Index Order VS Query Order ?? , Tuning Docs URL ?.

Hi,
I was working on optimising a piece of code which was taking 10hrs + to
execute and all.So my queries are..

#1) Saw a table where the "order of query" on the table and the "order =
of
key"
are different . For faster results shouldn't they be in the same order.

for eg:

Select ...   where A.ID =3D ... and A.Name =3D ...

The Key order on this table A  NOW is Name & ID Order .=20
Shouldn't they be in the order ID , Name ?..


#2) Can anybody recommend me any site , where I will get reliable
information on Tuning PL/SQL ?.


With thanks in advance=20

Ranjeesh


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References:
- Composite Index Order VS Query Order ?? , Tuning Docs URL ?.
  - From: Ranjeesh K R.

RE: Composite Index Order VS Query Order ?? , Tuning Docs URL ?.

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