[Chameleon] Slow Rectangluar Query Performance

LITTLE Nelson nelson.little at tenix.com
Thu Sep 6 04:27:51 EDT 2007

Hi all,

I am using the latest Chameleon and Mapserver on a Window machine
running MS Windows 2000 on a Pentium 4 2.8Ghz with 1Gb of RAM.

I have noticed that when I perform rectangular queries using the Query
Widget with highlighting turned on, the performance, or time taken for
a) the query to complete, and b) the highlighted features to become red
is quite poor. 

For example, doing a query which will return ~ 4 features (2 from one
layer and 2 from another layer) takes 10 seconds to show the Query
Results and 29 seconds to highlight the features in the display. 

Furthermore, I noticed that during the query in the process list the CPU
usages peaks at 100% a couple of times and that php-cgi.exe uses a bit
of memory and CPU.

My map file consists of shapefile layers and postgis layers, but the
postgis layers are very simple and FILTER on columns that have indexes.
The same machine where I am running the client application also runs the
Postgresql database and Apache web server.

Can anyone offer any help or advice as to why things seem to be slow? 


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