[Benchmarking] split contour files are different

[Jeff McKenna]

Iván Sánchez Ortega wrote:
> The real world case is 4000 shapefiles for the contour lines. Each from a 
> different year, different source, and different fields set to null.

exactly what I was going to say to you, commonly I have a theme split 
into hundreds or thousands of files (think of U.S. counties as an 
example).  So for me to have one contour layer for each county file 
(over 3,000) in a single configuration file is ha, quite funny.

-jeff