[GRASS-user] the performance of displaying vector attributes - with MySQL no difference!!

[Zbigniew Perski]

On Mon, 2006-11-13 at 11:51 +1300, Brent Wood wrote:
> Brad Douglas wrote:
> > On Sun, 2006-11-12 at 20:12 +0100, perski at uranos.cto.us.edu.pl wrote:
> >   
> >> I spent some time on it during last days and I sucesfully introduced MySQL database to grass.
> >> Unfortunately during displaying poits with colors from rgb columns THERE IS NO DIFFERENCE in performance comparing to dbf engine. After adding indexes to grassrgb column is still the same.
> >>
> >> Any other ideas hoe to speed up this task?
> >>     
> >
> > There are a number of things that can be done to speed up database
> > queries.  I suggest anyone who is using a true SQL database on the
> > backend, learn how to successfully normalize the database.  Here are a
> > few links about database normalization:
> >
> > http://en.wikipedia.org/wiki/Database_normalization
> > http://dev.mysql.com/tech-resources/articles/intro-to-normalization.html
> >
> > Different databases take different approaches to administration and
> > performance optimizations, but knowledge of SQL92 generally enough for
> > successful normalization.
Hi again,
the problem of my database is that I don't see any way to optimize it.
Imagine if you have 20 thousands of xyz points and want just to
visualize them in different colors (dem-like color scale). Each point
has its unique x,y,z values...
I tried to assign indexes for my "z" column using:
 
	ALTER TABLE my_points ADD INDEX(z_ccordinate);

And I don't see any difference in performance with e.g. v.univar.sh 
So maybe I am doing something wrong?

Cheers

Zbigniew