Re: [HACKERS] has anybody else used r-tree indexes in 6.5?

I read through some of the papers about R-trees and GIST about a year
ago,
and it seems that estimating costs for R-tree searches (and GIST
searches) is
not so straightforward as B-Trees. 

Hellerstein et al. 1995 write 
	"...currently such estimates are reasonably accurate for B+ trees
and   	less so for R-Trees. Recently, some work on R-tree cost
estimation 		has been done by [FK94], but more work is required to bring
this to 		bear on GISTs in general...." 

The reference that they give is 

[FK94] Christos Faloutsos and Ibrahim Kamel. "Beyond Uniformity and
Independence: Analysis of R-trees using the concept of fractal
dimension.
Proc. 13th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database
Systems, pp 4--13, Minneapolis, May 1994


I don't have the Faloustos paper.  The R-tree code authors, and the GIST
authors just used the B-Tree code as an expedient solution. 

Bernie Frankpitt