[OSM-talk] Tile caching (osm startpage)

[Bernhard zwischenbrugger]

John Smith schrieb:
> On 6 March 2010 01:24, Bernhard zwischenbrugger <bz at datenkueche.com> wrote:
>   
>> Google Cache Time:
>> Cache-Control: public, max-age=22222222  //feels like one month (I
>> didn't calculate)
>>     
>
> I'd say it's a bad idea to specify a cache time, instead there is
> other caching mechanisms to tell if a tile has changed:
>
>   
>> ETag: "d096ddafba32c0da609007e224530ccd"
>>     
>
> This way if a tile never changes you never need to refresh.
>   
But the browser sends the ETag to the server all the time. The server 
answers "304 not modified".

Phnom Penh load times:
To get the HTTP header of a picture takes here at the moment 1.3 seconds.
To load the picture it's about 2.5 seconds for a single picture.

An image that is already in cache takes about 1.3 seconds to load (must 
wait for 304 header).

This values are measured using "wget" and "HEAD" at commandline.

In browser the load time is even worse.

see: http://wiki.openstreetmap.org/wiki/File:Imageloadtime.png

Bernhard