Re: How does Oracle keep B-tree indexes to 3 levels?
- From: "Ryan" <ryan.gaffuri@xxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 5 Feb 2004 23:10:15 -0500
Is oracle the only database that is good at keeping the number of levels in
an index to a minimum? Or is it common amongst the other major dbms?
----- Original Message -----
From: "Cary Millsap" <cary.millsap@xxxxxxxxxx>
To: <oracle-l@xxxxxxxxxxxxx>
Sent: Thursday, February 05, 2004 11:04 PM
Subject: RE: How does Oracle keep B-tree indexes to 3 levels?
> You get a new level only if the parent node splits propagate all the way
> to the index root node. Jonathan Lewis and Steve Adams have some good
> tests in their courses that use block dumps to show how Oracle
> redistributes keys in branch blocks when nodes split.
>
> Yes, Oracle index nodes are one block apiece.
>
>
> Cary Millsap
> Hotsos Enterprises, Ltd.
> http://www.hotsos.com
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>
> -----Original Message-----
> From: oracle-l-bounce@xxxxxxxxxxxxx
> [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Ryan
> Sent: Thursday, February 05, 2004 9:32 PM
> To: oracle-l@xxxxxxxxxxxxx
> Subject: How does Oracle keep B-tree indexes to 3 levels?
>
> I'm taking an academic database class. My professor showed us that when
> you have a block split and the parent node(s) split, you end up with a
> new level. I'm assuming oracle 'redistributes' the pointers instead of
> adding a new level?
> Are index nodes always one block?
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