Eric Lemoine wrote:
Hi
I've observed that mapserv image rendering performance decreases
significantly with the number of layers. I currently have 500+ layers
in my mapfile and I see a huge performance hit if I decrease this
number to around 10. Is this expected? I use mapserver 4.10.
Thanks,
Sorry if this question has already been answered.
--
Eric
Eric,
I think Ed McNierney did some performance tests on this issue (you might
be able to find it in the archives).
Anyway the up shot is that you have to parse and allocate objects for
all the layers, symbols, styles, etc that are defined in all the layers
and this takes time.
There is also a performance hit if you are using projection definitions
because parsing all the projection init definitions is very time
consuming. Frank W. might have more info on this. I think some people
have made stripped down projection files with only the projections that
they are using, to speed this up for production use.
-Steve W
