Skip site navigation (1) Skip section navigation (2)

Re: Equivalent praxis to CLUSTERED INDEX?

From: Mischa Sandberg <ischamay(dot)andbergsay(at)activestateway(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Equivalent praxis to CLUSTERED INDEX?
Date: 2004-08-26 21:46:13
Message-ID: FSsXc.56332$X12.9135@edtnps84 (view raw or flat)
Thread:
Lists: pgsql-performance
Sheer nitpick here...

A B-tree is where the records (data) live at all levels of the tree;
B+ tree is where the records are only at the leaf level.
That's what Knuth calls them, anyway.

Clustered indexes for all known dbs are true B+ trees.
Nonclustered indexes could be B-trees (probably aren't),
since there's no big fanout penalty for storing the little
(heap) row locators everywhere at all levels.

J. Andrew Rogers wrote:
> As far as I know, Oracle does it by having a B-Tree organized heap (a
> feature introduced around v8 IIRC), basically making the primary key
> index and the heap the same physical structure.  
...

In response to

pgsql-performance by date

Next:From: Gregory S. WilliamsonDate: 2004-08-26 22:36:21
Subject: Re: Equivalent praxis to CLUSTERED INDEX?
Previous:From: Mischa SandbergDate: 2004-08-26 21:41:04
Subject: Re: Equivalent praxis to CLUSTERED INDEX?

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group