Re: RE: How does Oracle keep B-tree indexes to 3 levels?
- From: Tanel Põder <tanel.poder.003@xxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 18 Feb 2004 14:27:47 +0200
Hi Jonathan,
Is this a public paper you're talking about?
Tanel.
> ** Footnote - I used to believe it was supposed to
> be at 75% because on average a block was somewhere
> between half full and full - but I've given a reference to a
> paper that demonstrates that the failure to merge in real
> time leaves Oracle with a lower value. I haven't yet found
> time to read the paper, though.
>
>
> Regards
>
> Jonathan Lewis
> http://www.jlcomp.demon.co.uk
>
> The educated person is not the person
> who can answer the questions, but the
> person who can question the answers -- T. Schick Jr
>
>
> Next public appearances:
> March 2004 Hotsos Symposium - The Burden of Proof
> March 2004 Charlotte NC OUG - CBO Tutorial
> April 2004 Iceland
>
>
> One-day tutorials:
> http://www.jlcomp.demon.co.uk/tutorial.html
>
>
> Three-day seminar:
> see http://www.jlcomp.demon.co.uk/seminar.html
> ____UK___February
> ____UK___June
>
>
> The Co-operative Oracle Users' FAQ
> http://www.jlcomp.demon.co.uk/faq/ind_faq.html
>
>
> ----- Original Message -----
> From: <ryan.gaffuri@xxxxxxx>
> To: <oracle-l@xxxxxxxxxxxxx>
> Sent: Friday, February 06, 2004 1:58 PM
> Subject: Re: RE: How does Oracle keep B-tree indexes to 3 levels?
>
>
> so nodes can be as sparse as having 1-2 pointers in them? Doesnt this
> increase the size of the tree and decrease performance?
>
> also, does oracle use 'sparse' indexes. With standard dense indexes there
is
> a pointer to every record in the table. With sparse indexes you get
pointers
> to a range of records.
>
> For example.
>
> You have a column with
>
> 1
> 2
> 3
> 4
> 5
>
>
> You might have a pointer to '1' and a pointer to '5'. Does oracle use
this?
> >
>
>
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