Re: Index based database?

From: DA Morgan <damorgan_at_psoug.org>
Date: Sun, 17 Dec 2006 14:19:58 -0800
Message-ID: <1166393994.945333@bubbleator.drizzle.com>

EscVector wrote:
> Geoff Muldoon wrote:

>> Junk_at_webthere.com says...
>>> DA Morgan wrote:
>>>> Is is a "real" warehouse designed as one or just a copy of an OLTP schema?
>>>> Are they being used?
>>>> What index type?
>>> 1.  Kimbal Based Warehouse no legacy OLTP and no ODS, designed for
>>> warehouse/reporting
>>>
>>> 2.  Indexes being used:  not always - but that's another issue.
>>>
>>> 3.  Index type = B*Tree, all B*Tree
>> It is often common for indexes in a DW to be bitmap rather than b-tree.
>>
>> Good book by Bert Scalzo specifically on Oracle/DW/star schemas is worth a
>> read.
>>
>> GM

>
> Yes, I have all of Bert's books, the toad suff is a little old now.
> Kimball's too; autographed even.
>
> Thanks for the reply, it indicates I still have my sanity. Bitmap is
> key, but we have none on this database.

"Innocently" ask your data modeler the following question:

"When, in Oracle, should I consider creating bitmap, bitmap join, compressed, iot, cluster, and other index types rather than the default B*Tree indexes?"

The answer will tell you everything you need to know. And I suspect I already know what it will be.

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu
(replace x with u to respond)
Puget Sound Oracle Users Group
www.psoug.org

Received on Sun Dec 17 2006 - 16:19:58 CST