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Re: Index rebuild vs. coalesce

From: <bulbultyagi_at_now-india.net.in>
Date: Thu, 22 May 2003 12:56:56 -0800
Message-ID: <F001.005A0AD2.20030522125656@fatcity.com>


Advantages of rebuild over coalesce
1. Can move the index to another tablespace. 2. Can rebuild the index using new storage parameters without dropping the original index.
3. Higher costs because requires more disk space. Coalescing is an in-place data reorganization operation therefore it does not require addintional disk space like rebuild.
4. Creates a new tree this can shrink the height of the tree if applicable. Coalescing will coalesce the leaf blocks within same branch of the tree. 5. Can compute statistics ( not estimate statistics ) while rebuilding indexes.
6. Can convert an existing normal b-tree index into a reverse key index 7. Finally you would rebuild and not coalesce when the table of the index has been moved to another tablespace .
----- Original Message -----
To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Thursday, May 22, 2003 20:47

> What do I get from an index rebuild that I do not get from
> simply coalescing the index?
>
> Thanks,
> Peter Schauss
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: Schauss, Peter
> INET: pschauss_at_northropgrumman.com
>
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Author: <bulbultyagi_at_now-india.net.in
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Received on Thu May 22 2003 - 15:56:56 CDT

Original text of this message

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