[Chameleon] performance concerns

openwereld.net openwereld.net at home.nl
Sun May 8 15:14:35 EDT 2005

Hi Bart,

Bart van den Eijnden schreef:

> 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).

The Neapoljs site doesn't display anything with Firefox under Linux, so 
it can't be that special ;-)

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

Thoughts are probably easier than implementing solutions.  They are 
probably often phrased in this mailing list. I am trying myself with 
using Smarty to generate cached pages (fast indeed, and multilanguage 
also) and most things are done in javascript on the client. The MapDHTML 
widget uses XmlHttp to communicate with MapScript on the server and 
returns only a url to a new image.
Note that the speed of the database access (adodb, sqlite) is only of 
importance when the cache needs to be refreshed.

> Thanks in advance.

You're welcome ;-)

> Best regards,
> Bart

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