Re: IOT Vs Normal Tables

Jared,

Since the index and data are stored together, my impression on this subject was IOT's will save you the extra I/O for the data lookup.

With the B-TREE index structure being common, the savings should be in the data lookup.

Also, from the Oracle Internals class I had the opportunity to attend in October, at Hustone TX, the instructor told us that with 9i the data dictionary will be using IOT.

I have not tested it myself, but these are from training, conversations and reading knowledge.

Murali Vallath
Oracle Certified DBA
http://www8.ewebcity.com/muralivallath
http://www.summerksyus.com/

From: jared still <jkstill_at_teleport.com> Reply-To: ORACLE-L_at_fatcity.com
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> Subject: Re: IOT Vs Normal Tables
Date: Wed, 13 Dec 2000 20:35:31 -0800

On Wed, 13 Dec 2000, Sanjay Kumar wrote:

> Hi,
>
> Can anyone tell me how to see the performance differences of using IOTs
over the normal tables.
>
> Sanjay
>

I don't think you will see any performance increase from an IOT.

You can get the same performance if your query can be satisfied by an index without reading the table. i.e. the index has all the columns to satisfy the query.

IOT's just save space and complicate your life. :)

Jared Still
Certified Oracle DBA and Part Time Perl Evangelist ;) jkstill_at_teleport.com
jared_still_at_enron.net

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