[Mapserver-users] PostGIS / Shapefile Performance Question

[Lowther, David W]

Hi List,

Has anybody experimented with drawing / query time of features from
shapefiles vs. features from PostGIS?

My experience (and it is extremely limited) is as follows. This is why I am
asking about your experiences.

Drawing a layer based on a shapefile that is located on the same physical
drive as mapserver is faster then drawing that same layer from PostGIS
running on a separate machine. But obviously this is a result of several
factors including the network connection (in this case 100 megabit on both
machines), the hardware in the Postgres server (in this case 233mhz, 128mb
ram), and the traffic (in this case just what I am doing by testing).

Are there certain situations in which the access to PostGIS might be quicker
then a shapefile, say when zoomed in closely or zoomed way out or when doing
a point based query?

Is there a point where the number of features in a layer would cause PostGIS
or shapefiles to perform better?

What if I put a monster of a machine in place as the postgres server? Could
I build a postgres server that would be as fast as shapefiles local to
mapserver?

What happens as the application scales? If I saw traffic like mapquest.com
or something would shapefiles be faster than PostGIS?

Sorry if this seems irrelevant or silly line of questions. I just have a
conflict between the convenience / queryability of PostGIS and the speed of
shapefiles.

Thanks,

Dave Lowther