[Users] onload time

[Marc Jansen]

Hi Robert,

find answers inline.


On 14.09.2010 15:43, Robert Buckley wrote:
> hi,
>
> my app takes (according to firebug)
>
>
> ...39.87s (onload: 26.93s)
>
>
> This is rather long for an app which isn´t really big.
>
>
> Do the following make a difference to the loading time?
>
>   - Minifying the js?
>    

Yes, minifying reduces the ammount of code to be transmitted from server 
to client.

>   - removing the parts of ext.js that are not used ..ie custom build
>    

Yes, as fewer bytes need to be transported.

>   - removing the parts of openlayers.js that are not used..ie custom build
>    

Yes, see above.
>   - using postgis instead of shapefiles
>    

IMO: No. the onload event shouldn't wait for the WMS-images to be 
returned, as you initialize the layers after wards, right. As for the 
performance of the WMS: It depends, more often than not I found 
shapefiles to be the fastes possibility. Shapefiles might have some 
deficiencies, performance was seldom one for me.

>   - removing all js from the html doc
>    

IMO: Yes, as external ressources can be cached by the browser, whereas 
inline JS cannot

>
>
>
> are there any others?...which has the best result regarding performance and
> useability?
>
>    

gzip your css/html/Javascript.

generally follow the rules from yslow or google speed.
http://developer.yahoo.com/yslow/help/
http://developer.yahoo.com/performance/rules.html
http://code.google.com/speed/page-speed/
http://code.google.com/speed/page-speed/docs/rules_intro.html

Andreas (Hocevar) held a talk at this years FOSS4G with other 
recommendations regading performance:
http://2010.foss4g.org/presentations_show.php?id=3335

Maybe they put up the slides/link of the presentation sometime soon.

Regards,
Marc

> Cheers for any thoughts,
>
>
> Rob
>
>
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>
>    


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   Dipl.-Geogr. Marc Jansen
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