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Home -> Community -> Mailing Lists -> Oracle-L -> RE: re Rebuilding Indexes in Oracle Apps -- was RE: RE:
Well, in a small step in our defense, it DOES state at the top of the note:
and in an even larger step, the author of the document has been asked to review and correct it.
Pete
"Controlling developers is like herding cats."
Kevin Loney, Oracle DBA Handbook
"Oh no, it's not. It's much harder than that!"
Bruce Pihlamae, long-term Oracle DBA
-----Original Message-----
Jared.Still_at_radisys.com
Sent: Saturday, October 18, 2003 5:35 AM
To: Multiple recipients of list ORACLE-L
The article states that leaf blocks are not reused, which is indeed
incorrect,
and has been for a very long time.
Hemant K Chitale <hkchital_at_singnet.com.sg> Sent by: ml-errors_at_fatcity.com
10/17/2003 11:42 AM
Please respond to ORACLE-L
To: Multiple recipients of list ORACLE-L
<ORACLE-L_at_fatcity.com>
cc:
Subject: Re: re Rebuilding Indexes in Oracle Apps -- was RE:
RE:
I wonder if "it is not necessary to rebuild indexes" is also a myth.
It IS in some cases necessary
1. Indexes on monotonically increasing values [eg Conrurrent_Request_ID
based on a Sequence
or even on date columns which signify when the record is created] if the
table is also
purged by the same columns frequently
2. Because the disk space used by an Index can be inordinately larged
after a couple of years
and index fast_full_scans are impacted
Have you administered an Oracle Applications database ? hemant
At 03:29 AM 17-10-03 -0800, you wrote:
>Hi Hemant,
>
>One word perfectly describes the Metalink article you highlighted:
>
>Crap ;)
>
>A nice example of how Oracle Corp is the greatest myth generator of them
>all !! It's all rather sad and embarressing isn't.
>
>Thanks for the headsup. Anyone in a position to get the note removed ?
>
>Cheers
>
>Richard
>
> >Quoting Metalink Note 182699.1 bde_rebuild.sql Validates and Rebuilds
>Fragmentated Indexes (8.0->9.0)
> >
> >Index fragmentation occurs when a key value changes, and the index row is
> >deleted from one place (Leaf Block) and inserted into another.
> >
> > Deleted Leaf Rows are not reused. Therefore indexes whose columns are
> >subject to value change must be rebuilt periodically since they become
>naturally fragmentated.
> >
> >An index is considered to be 'fragmentated' when more than 20% of its
Leaf
>Rows space is
> >empty because of the implicit deletes caused by indexed columns value
>changes.
> >
> >Fragmentated indexes degrade the performance of index range scan
>operations.
>
>
>--
>Please see the official ORACLE-L FAQ: http://www.orafaq.net
>--
>Author: Richard Foote
> INET: richard.foote_at_bigpond.com
>
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Hemant K Chitale
Oracle 9i Database Administrator Certified Professional
My personal web site is : http://hkchital.tripod.com
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Hemant K Chitale INET: hkchital_at_singnet.com.sg Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- 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). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Pete Sharman INET: peter.sharman_at_oracle.com Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- 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 Fri Oct 17 2003 - 17:09:24 CDT
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