RE: bitmap join indexes

From: Gogala, Mladen <MGogala_at_allegientsystems.com>
Date: Wed, 19 Oct 2005 10:03:36 -0400
Message-ID: <A2C7821363A0544987988F6BCCE941B5060915@pegasus.lawaudit.com>

Ottar, I see that you are converting bitmap to rowid and are accessing CL_CENTRAL through some form of B-Tree index. Have you tried all bitmap indexes and star schema? I'm actually an OLTP guy, but the best book on the topic is "Essential Oracle8i Data Warehousing". One of the authors of the book also has an excellent website: http://www.evdbt.com.

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Mladen Gogala
Ext. 121
-----Original Message-----

From: Ottar Soerland [mailto:OSoerland_at_caci.co.uk] Sent: Wednesday, October 19, 2005 5:05 AM To: oracle-l_at_freelists.org
Subject: bitmap join indexes

Hi all,

here's the background to my problem: I have 4 large tables (40 mill records) - each with an id (same id for all of them) and lots (100-300) of low-cardinality columns ('classification'-columns). The objective is to be able to do a fast count of the id's across the tables based on various criteria for the 'classification' columns. I also need to be able to add tables of the same format ideally without having to rebuild the whole thing.

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http://www.freelists.org/webpage/oracle-l Received on Wed Oct 19 2005 - 09:03:21 CDT