VS: [mapserver-users] Mapserver search performance

[Rahkonen Jukka]

Hi,

Shptree will help and stopwatch will tell you how much. Without spatial
index Mapserver needs to go through the whole shapefile every time. Have
a try, it will not take very many seconds to run shptree. Make different
requests, take times with and without .qix files and you will some
numbers. Change the requests and request order (query 1 with
.qix/withour qix, query 2 without .qix/with .qix) so that you can see if
you are actually testing the speed of disk access and memory cache
access and not the effect of having spatial index.
By adding DEBUG 5 for your layer you don't need stopwatch but you'll get
timings into ms_errorfile.


-Jukka Rahkonen-

Varun saraf wrote:

> 
> Hello Everyone,
> 
> I have programmed a GIS application using Mapserver, Google maps and
> Tilecache. The functionality of this GIS application is to extract the
> data (from the dbf file) for all features (Points) within a randomly
> drawn user shape and doing some statistical operation on that data. I
> use an NQUERY mode with MAPSHAPE attribute to get all the data for the
> user drawn shape. Mapserver takes aout 5-10 seconds for a small shape
> (a couple of square miles) but as the shape gets bigger (hundreds of
> square miles), the time taken to fetch all data related to the
> features/points lying in the shape grows exponentially (Upto 2 hours
> for some shapes). Until now, we were restricting the maximum area a
> shape can have but we have to get rid of that. Is there a way to
> improve the performance in any way? Will SHPTREE work for this
> purpose? The features are currently points only but we may move to
> polygons in future. We use the .shp files for the shapes. Is it
> advantageous to move to a database instead? If yes, what database
> works best?
> 
> What I did notice is that for any given request to mapserver, however
> large the shape, the CPU utilization never crosses 12%. Can we improve
> performance by increasing the RAM or maybe move to a solid state hard
> drive? There is also the possibility of moving this application to
> Cloud computing. Anything that will improve the performance actually.
> Can someone point me in the right direction as to what might be the
> current bottleneck?
> 
> T current setup is on windows and uses MS4W on an Apache server.
> 
> Thanks,
> Varun
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