Re: Use "average field correlation per hard disk

At 04:08 PM 10/03/2004, Tom Lane wrote:
>None at the moment, but I'm open to suggestions.  It seems like we might
>need different stats for equality probes than range probes.

What about my suggestion from August 2000:

     "There might be a way to side-step the issue here. I assume that
     the index nodes contain a pointer to a record in a file, which
     has some kind of file position. By comparing the file positions
     on one leaf node, and then averaging the node cluster values,
     you might be able to get a pretty good idea of the *real* clustering."

I don't use the CLUSTER command, but I have clustered data and would like 
to be able to take advantage of the fact if possible. *If* the record 
pointers can be used to indicate closeness, then the same approach of 
randomly sampling index nodes would seem to work. Then again, maybe I don't 
know enough about the storage techniques...




----------------------------------------------------------------
Philip Warner                    |     __---_____
Albatross Consulting Pty. Ltd.   |----/       -  \
(A.B.N. 75 008 659 498)          |          /(@)   ______---_
Tel: (+61) 0500 83 82 81         |                 _________  \
Fax: (+61) 03 5330 3172          |                 ___________ |
Http://www.rhyme.com.au          |                /           \|
                                  |    --________--
PGP key available upon request,  |  /
and from pgp.mit.edu:11371       |/