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RE: When to rebuild the index?

From: Goulet, Dick <DGoulet_at_vicr.com>
Date: Tue, 6 Sep 2005 15:29:17 -0400
Message-ID: <4001DEAF7DF9BD498B58B45051FBEA6502C8B5C9@25exch1.vicorpower.vicr.com>


Jared,  

    I agree. Most indexes require little if any attention. Those that go through rapid growth are worth attention & 99% of the time something in the application is the root cause. We rebuild indexes periodically to placate damagement (read that as Damage Management) so that the end user feels the DBA staff is doing something to handle their pain. Sometimes a little "false" information (politically correct term for a lie) is a good thing, sometimes not. The only good thing I've found comes from a rebuild exercise is that you get back some space in your index tablespace, somewhere between 1 and 5 percent with a definite bias towards the former. In general it's normally an exercise in futility, desperation, or both.


From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Jared Still Sent: Tuesday, September 06, 2005 2:46 PM To: chiragdba_at_gmail.com
Cc: Allen, Brandon; Oracle-L Freelists
Subject: Re: When to rebuild the index?

I don't have time to read the entire article, so I skipped down to the summary:

Re the Academic approach: much evidence has been supplied regarding this.
I am not going to attempt to rehash it. Look on AskTom. Search for Richard
Foote's presenation on index internals.

Re the pragmatic approach: If the users just need a placebo, then lie to them.
Tell them the indexes were rebuilt and they will be happy. Speed increases
do to index rebuilding in an OLTP system are only temporary. It is entirely
possible that rebuilding index will hurt performance as the index blocks

re-split due to inserts.

Oops, there I go, rehashing.

-- 
Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist
11+ years of trying to appear to know what I'm doing.




On 9/6/05, Chirag DBA <chiragdba_at_gmail.com> wrote: 

	Hi,
	 
	http://www.dba-oracle.com/art_dbazine_idx_rebuild.htm
	 
	Here is the very good document for indexes.
	 
	I just found that. 
	
	 
	Regards - Chirag
	
	 
	On 9/6/05, Chirag DBA <chiragdba_at_gmail.com > wrote:



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Received on Tue Sep 06 2005 - 14:31:28 CDT

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