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Re: SQL Tuning Question

From: Karl R. <kreitsch_at_zdnetonebox.com>
Date: 2000/05/11
Message-ID: <06da2e58.ac5cbb4b@usw-ex0105-034.remarq.com>#1/1

Hello Roy

Try to us an bitmap-index on this column

Bitmapindexes includes NULL-Valued-Columns too

In Server -Concepts for 8i you can read in Chapter Schemaobjects  10-35 you can read :

Bitmap Indexes and Nulls
Bitmap indexes include rows that have NULL values, unlike most other types of
indexes. Indexing of nulls can be useful for some types of SQL statements, such as
queries with the aggregate function COUNT.

Importent is that the table is not heavy accessed with updates on the index column because bitmapped-indexes are locking many rows due to their design!

A Buffer Cache Hit Rate with 50% is amazing, there seems to be some gfull-tablecans ond different tables.

Regards
/Karl

Karl Reitschuster
Senior Consultant CSC Ploenzke AG
Oracle Databases, Implementation, Performance-Tuning <!Jesus is Lord!>
* Sent from RemarQ http://www.remarq.com The Internet's Discussion Network * The fastest and easiest way to search and participate in Usenet - Free! Received on Thu May 11 2000 - 00:00:00 CDT

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