B-Tree index

From: Norman Dunbar <Norman.Dunbar_at_lfs.co.uk>
Date: Wed, 6 Nov 2002 16:20:49 -0000
Message-ID: <E2F6A70FE45242488C865C3BC1245DA702E3DDDF@lnewton.leeds.lfs.co.uk>

OCP point of note coming up !

And don't forget to check V$INDEX_STATS out as soon as you analyse the index because when you analyse the next index your stats vanish - it one row at a time with this view !

Cheers,
Norman.

Norman Dunbar
Database/Unix administrator
Lynx Financial Systems Ltd.
mailto:Norman.Dunbar_at_LFS.co.uk

Tel: 0113 289 6265
Fax: 0113 289 3146
URL: http://www.Lynx-FS.com
-------------------------------------

-----Original Message-----
From: news_at_igsrsparc2.er.usgs.gov (Janet Walz (GD) x6739) [mailto:news_at_igsrsparc2.er.usgs.gov]On Behalf Of Brian Peasland Posted At: Wednesday, November 06, 2002 3:44 PM Posted To: server
Conversation: B-Tree index
Subject: Re: B-Tree index

Your B-tree index will always be balanced. That's part of its definition! What you really want to check is to see if the leaf nodes are "empty". You can do this by issuing the following command:

ANALYZE INDEX index_name VALIDATE STRUCTURE;

Then query V$INDEX_STATS comparing the deleted leaf nodes to the total number. If this percentage is too high, then rebuild the index.

HTH,
Brian

Harry Sheng wrote:
>
> How can I check if a B-Tree index (suppose it is not too big) is well
> balanced ?
Received on Wed Nov 06 2002 - 10:20:49 CST