Re: RE: How does Oracle keep B-tree indexes to 3 levels?
- From: <ryan.gaffuri@xxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Wed, 18 Feb 2004 7:53:48 -0500
the 67% percent full is actually in my college textbook. so its probably =
somewhat standard. =
> =
> From: Tanel P=F5der <tanel.poder.003@xxxxxxx>
> Date: 2004/02/18 Wed AM 07:27:47 EST
> To: <oracle-l@xxxxxxxxxxxxx>
> Subject: Re: RE: How does Oracle keep B-tree indexes to 3 levels?
> =
> 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 t=
here
> 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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> =
> =
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