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RE: Weirdness

From: Johnston, Tim <TJohnston_at_quallaby.com>
Date: Thu, 25 Oct 2001 11:56:18 -0700
Message-ID: <F001.003B4D80.20011025115523@fatcity.com> 









Maybe you post the explain plans from the two scenarios with the statistics of your run times?  Did you run the test multiple times?  Was there any other activity on the system while running your tests?



Tim




-----Original Message-----


From: Kimberly Smith [mailto:kimberly.smith_at_gmd.fujitsu.com]
Sent: Thursday, October 25, 2001 1:17 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: Weirdness





That is my whole question.  I did make it an IOT and performance
suffered.  I was surprised by that.




-----Original Message-----


Sent: Thursday, October 25, 2001 9:36 AM
To: Multiple recipients of list ORACLE-L





Kimberly - Have you considered making this an index-organized table?
Available in the most recent versions of Oracle.
Dennis Williams


DBA



Lifetouch, Inc.


dwilliams_at_lifetouch.com





-----Original Message-----


Sent: Thursday, October 25, 2001 11:16 AM
To: Multiple recipients of list ORACLE-L





Its one index with all the columns.  This is why I was thinking it would
be the same or similar performance.  The execution path is fine and 
considering how many rows I am dealing with the execution is more then
fine.  I was trying to reduce storage and speed up the loads a bit.




-----Original Message-----


Sent: Thursday, October 25, 2001 1:40 AM
To: Multiple recipients of list ORACLE-L





Depends whether each column has a separate index on it, or all columns are
in a single concatenated index.  An IOT is like the latter - it's only going
to help if you are always using the same (or similar) access path.  




Oracle doesn't go to a table if it can get all the values it needs from an
index.  So, I suspect that the performance of an IOT may not be any better
than a suitable concatenated index.  It simply saves you from storing the
data twice.




> -----Original Message-----

> From: Kimberly Smith [mailto:kimberly.smith_at_gmd.fujitsu.com]

> Sent: 24 October 2001 18:55

> To: Multiple recipients of list ORACLE-L

> Subject: Weirdness

> 

> 

> Oracle 8.1.7.1 on HPUX 11 

> 

> I have a table that I have just indexed every column.  This 

> has improved the

> query performance however, its going to slow down the load.  

> Thing that has

> me confused is that I tried this as an IOT and it actually 

> hurt performance.

> This table is joined to another table 3xs.  The table I made 

> an IOT has >2

> million rows and the other table has >6 million rows.  

> Shouldn't the IOT

> table have had similar performance to having every column indexed?

> 

> 

> 

> ________________________________________

> Kimberly Smith

> GMD Fujitsu

> Database Administrator

> (503) 669-6050

> 

> -- 

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

> -- 

> Author: Kimberly Smith


>   INET: kimberly.smith_at_gmd.fujitsu.com




> 

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> 








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-- 
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-- 
Author: Kimberly Smith
  INET: kimberly.smith_at_gmd.fujitsu.com


Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
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-- 
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-- 
Author: DENNIS WILLIAMS
  INET: DWILLIAMS_at_LIFETOUCH.COM


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San Diego, California        -- Public Internet access / Mailing Lists
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-- 
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-- 
Author: Kimberly Smith
  INET: kimberly.smith_at_gmd.fujitsu.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
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Received on Thu Oct 25 2001 - 13:56:18 CDT












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