Re: Resources for tuning DW (star_transformation fact) queries
- From: "Michael McMullen" <ganstadba@xxxxxxxxxxx>
- To: <somckit.khemmanivanh@xxxxxxxxxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 22 Nov 2005 14:17:37 -0500
I always look for some type of summary functions in the where clause
ie.
where orderdate = (select max(something) from blah where a. = b. )
and then rewrite as analytical.
look for same statement being called over and over and rewrite as with
clause
look for joins which are used just to get a lookup value and rewrite as
in-line selects.
look for things obviously not right. like outerjoins with where conditions
on the outer-joined table,or functions in the where clause
ie
select *
from
a.blah, b.blah
where a.x = b.x(+)
and upper(b.something) = 'xxx'
Mike
ganstadba@xxxxxxxxxxx
----- Original Message -----
From: Khemmanivanh, Somckit
To: oracle-l@xxxxxxxxxxxxx
Sent: Tuesday, November 22, 2005 2:01 PM
Subject: Resources for tuning DW (star_transformation fact) queries
Hi,
Can anyone recommend some resources for getting started on tuning these
types of massive DW queries.
The explain plans on these queries can be pages and pages long, which is a
little overwhelming at first.
I'm looking for some quick tips from the experts to help me get started :)
Thanks much.
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