Re: RE: How does Oracle keep B-tree indexes to 3 levels?

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Thu, 19 Feb 2004 19:39:17 -0000
Message-ID: <006701c3f720$10a1f710$6702a8c0@Primary>

I believe the following covers the significant points - but I am not certain how accurate it is:

B-tree splits 50/50 on full

B+tree does the same, but leaf nodes have

forward and backward pointers

B*tree attempts to move rows to adjacent leafs if they can, and split 2 leafs into 3 if they can't (and maintain forward and backward pointers).

Regards

Jonathan Lewis
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Original Message ----- From: "Powell, Mark D" <mark.powell_at_eds.com> To: <oracle-l_at_freelists.org> Sent: Thursday, February 19, 2004 2:56 PM Subject: RE: RE: How does Oracle keep B-tree indexes to 3 levels?

OK, What is the high level difference between a B*Tree and a B+Tree? When I was in college I remember discussions on Btrieve and (Balanced) Binary trees, where each node has at most two children. The terminology seems to have changed over the years. Fortunately we never got to Red/Black trees and a couple of other variations.

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Received on Thu Feb 19 2004 - 13:39:17 CST