Re: IOT Vs Normal Tables

From: aaaa wwwwww <krisibm_at_lycos.com>
Date: Tue, 19 Dec 2000 18:50:13 -0800
Message-Id: <10715.124979@fatcity.com>
Jared
Some instructors do confuse their students
Rao
--

On Sun, 17 Dec 2000 22:41:04  
 jared still wrote:


>

>Murali,

>

>If your query can be satisfied by the columns in an

>index, and the optimizer chooses that index, the 

>table will not be read at all.

>

>Thus, the IOT will not offer any performance improvements

>in this case.

>

>This is well documented in the Oracle documentation if you

>care to take a look.  ( I'm too lazy tonight to look it up :)

>

>Jared

>

>On Fri, 15 Dec 2000, Murali Vallath wrote:

>

>> 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/

>> 

>> Reply-To: ORACLE-L_at_fatcity.com

>> To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>

>> 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

>> 

>> --

>> Please see the official ORACLE-L FAQ: http://www.orafaq.com

>> --

>> Author: jared still

>>    INET: jkstill_at_teleport.com

>> 

>> Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051

>> San Diego, California        -- Public Internet access / Mailing Lists

>> --------------------------------------------------------------------

>> To REMOVE yourself from this mailing list, send an E-Mail message

>> to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in

>> the message BODY, include a line containing: UNSUB ORACLE-L

>> (or the name of mailing list you want to be removed from).  You may

>> also send the HELP command for other information (like subscribing).

>> 

>> _________________________________________________________________

>> Get your FREE download of MSN Explorer at http://explorer.msn.com

>> 

>> -- 

>> Please see the official ORACLE-L FAQ: http://www.orafaq.com

>> -- 

>> Author: Murali Vallath

>>   INET: murali_vallath_at_hotmail.com

>> 

>> Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051

>> San Diego, California        -- Public Internet access / Mailing Lists

>> --------------------------------------------------------------------

>> To REMOVE yourself from this mailing list, send an E-Mail message

>> to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in

>> the message BODY, include a line containing: UNSUB ORACLE-L

>> (or the name of mailing list you want to be removed from).  You may

>> also send the HELP command for other information (like subscribing).

>> 

>

>Jared Still

>Certified Oracle DBA and Part Time Perl Evangelist ;)

>jkstill_at_teleport.com

>jared_still_at_enron.net

>

>-- 

>Please see the official ORACLE-L FAQ: http://www.orafaq.com

>-- 

>Author: jared still

>  INET: jkstill_at_teleport.com

>

>Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051

>San Diego, California        -- Public Internet access / Mailing Lists

>--------------------------------------------------------------------

>To REMOVE yourself from this mailing list, send an E-Mail message

>to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in

>the message BODY, include a line containing: UNSUB ORACLE-L

>(or the name of mailing list you want to be removed from).  You may

>also send the HELP command for other information (like subscribing).
Received on Tue Dec 19 2000 - 20:50:13 CST