Hi all,

Not sure if this is useful, but it might be good to file and reference
somewhere.

Regards and best wishes,

Justin Clift

-------- Original Message --------
Subject: Re: [GENERAL] Unisersal B-Tree
Date: Mon, 30 Apr 2001 17:59:49 +0200
From: Jï¿½rg Schulz <jschulz@sgbs.de>
Organization: Gebï¿½udereinigung Schulz
To: "Justin Clift" <justin@postgresql.org>
References: <9cb797$642$1@news.tht.net>
<3AEB9B33.EA886A2B@postgresql.org> <001b01c0d143$b9b33f40$0600a8c0@opal>
<3AED60D9.37A9028A@postgresql.org>

> Do you mind if I forward this email to the pgsql-hackers@postgresql.org
> mailing list?
>
Of cource you can forward it. Maybe you can correct my bad english :-)

Jï¿½rg Schulz

----- Original Message -----
From: "Justin Clift" <justin@postgresql.org>
To: "Jï¿½rg Schulz" <jschulz@sgbs.de>
Sent: Monday, April 30, 2001 2:55 PM
Subject: Re: [GENERAL] Unisersal B-Tree


> Hi Jï¿½rg,
>
> I know we have indices and sub-indices, but this also sounds
> interesting.
>
> Do you mind if I forward this email to the pgsql-hackers@postgresql.org
> mailing list?
>
> Regards and best wishes,
>
> Justin Clift
>
> Jï¿½rg Schulz wrote:
> >
> > Hi Cliff,
> >
> > I've read an article in the german magazine c't (2001/1 P174) about this
> > new astonishing method. After I realized that none of the major commercial
> > databases implement this for now (afaik there is only one database on the
> > market "Transbase HyperCube" www.transaction.de), I thought it would be a great
> > chance for an open source database. I even think it's a "must have feature"
> > in the near future.
> >
> > But what is it about? It can dramatically speed up queries that run over more
> > than one index. Think of a query like this:
> >
> > select a,b,c from table where ( a>min_a and a<max_a ) and ( b>min_b and b<max_b )
> >
> > In a conventional implementation you have two indexes on attributes a and b.
> > But to run this query the database engine profits only from one index. It has
> > to run through all the values of the other. This gets even worse if you use more
> > constraints, and this scheme is typical for things like OLAP.
> >
> > With the new methode you add one UB-index that embraces a and b. And you run
> > only once through this index.
> >
> > There are a number of papers available under mistral.in.tum.de that explain
> > the basic concepts.
> >
> > Regards,
> >
> > Jï¿½rg Schulz
> >
> > ----- Original Message -----
> > From: "Justin Clift" <justin@postgresql.org>
> > To: "JXrg Schulz" <jschulz@sgbs.de>
> > Sent: Sunday, April 29, 2001 6:40 AM
> > Subject: Re: [GENERAL] Unisersal B-Tree
> >
> > > Hi Jï¿½rg,
> > >
> > > What advantages do they have?
> > >
> > > Regards and best wishes,
> > >
> > > Justin Clift
> > >
> > > JXrg Schulz wrote:
> > > >
> > > > Are there any plans to implement UB-Trees
> > > > multidimensional indexes?
> > > >
> > > > Jï¿½rg Schulz
> > > >
> > > > ---------------------------(end of broadcast)---------------------------
> > > > TIP 6: Have you searched our list archives?
> > > >
> > > > http://www.postgresql.org/search.mpl
> > >
> > > --
> > > "My grandfather once told me that there are two kinds of people: those
> > > who work and those who take the credit. He told me to try to be in the
> > > first group; there was less competition there."
> > >      - Indira Gandhi
> > >
>
> --
> "My grandfather once told me that there are two kinds of people: those
> who work and those who take the credit. He told me to try to be in the
> first group; there was less competition there."
>      - Indira Gandhi
>

Tue, 01 May 2001 08:53:31 +1000
Justin Clift <justin@postgresql.org>
[Fwd: Re: [GENERAL] Unisersal B-Tree]
> ... Think of a query like this:
> 
> select a,b,c from table where ( a>min_a and a<max_a ) and ( b>min_b and b<max_b )
> 
> In a conventional implementation you have two indexes on attributes a and b.
> But to run this query the database engine profits only from one index. It has
> to run through all the values of the other. This gets even worse if you use more
> constraints, and this scheme is typical for things like OLAP.
> 
> With the new methode you add one UB-index that embraces a and b. And you run
> only once through this index.

And this is different from a multicolumn btree index how?

I looked at the referenced website when this message first went by,
and was unhappy at the apparently proprietary nature of the technology
(not to mention the excessive hype ratio).  I lost interest ...

			regards, tom lane

Fri, 04 May 2001 15:56:10 -0400
Tom Lane <tgl@sss.pgh.pa.us>
Re: [Fwd: Re: [GENERAL] Unisersal B-Tree] 