[Chameleon] performance concerns

Jacob Delfos jacob.delfos at maunsell.com
Sun May 8 20:46:15 EDT 2005

Hi Bart,

I think you should be careful comparing with results from a laptop. We have a laptop as well, which is significantly slower than a desktop. I think it's mostly due to harddisk speed. Also, it matters a lot whether the laptop is both the server and the client. Laptops make poor servers..... I don't think it's so much the reading of the mapfile, though....

We also care a lot about performance. To be honest, I would not deploy a chameleon site without javascript, because I fear clients would complain about speed. For this reason, everything we deployed so far is version 1 based (where I got the javascript working flawlessly and quick). I don't know whether javascript works without errors yet in version 2 (my CVS has been down for a month, due to the company firewall being misconfigured). I spent many days trying to figure out the extent bug in version 2 (http://www.maptools.org/bugzilla/show_bug.cgi?id=989).

I have been thinking of trying to modify a chameleon site, to experiment with submitting to an iframe. All the iframe would need to do, is update the scalebar, legend, and mapimage. I don't think I'd have to change that much in the code.



-----Original Message-----
From: chameleon-bounces at lists.maptools.org [mailto:chameleon-bounces at lists.maptools.org] On Behalf Of Bart van den Eijnden
Sent: 8 May 2005 22:46
To: chameleon at lists.maptools.org
Subject: [Chameleon] performance concerns

Hi list,

I am comparing an application built with Chameleon (based on the ROI  
sample app) with an application built with Neapoljs (Tydac's product built  
on PHP/Mapscript).

Neapoljs is more client-side oriented, ie the only thing it updates most  
of the time is the map image. So more like Chameleon's js api I guess.

I notice a huge performance difference using a 30 Kb MAP file with local  
datasets (shapefile and mapinfo) between Neapoljs and Chameleon, around a  
factor 2 or 3 per zoom in. This worries me a bit, as the response times of  
Chameleon are above 5 seconds on my local (quite fast) laptop.

I can imagine storing (writing/reading) the whole 30 Kb MAP file as a  
state in the session with every zoomin can be quite a bit of overkill,  
seeing the only line that is gonna change is the extent most of the time.  
Especially in applications where users can't influence the layers'  

Any thoughts on the performance? What could I try to speed it up? Are  
there any plans for optimizing performance?

Thanks in advance.

Best regards,

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