[OSM-dev] Mapnik's speed rendering slow ?

[sylvain letuffe]

> 0.5s per tile looks about right. The main tile server does not manage
> to render all z18 tiles in 24 hours.
Glups then...

(...)
> http://wiki.openstreetmap.org/index.php/Mod_tile

Thanks all for the link, I already had a look at mod_tile and I first thought 
it wouldn't fit my needs and then be a second choice.

I'm willing to (did I say dreaming ?)
1) have a max older tile of 24h
2) don't kill my server under load
3) have a fast responsive Openlayer (which I have with all tiles generated)

mod_tile seams to me not beeing able to cover 3 (unless someone got the pain 
to explore the same place before you, or unless we drop under ~0.02s per 
tiles, in wich case I'll stop bothering with caching tiles and have them 
rendered real-time )

2->, as of the readme, is not completly sure, unless some users are kicked 
off. because If simultaneously, 20 users are exploring a "new" region 
somewhere in mountain, the 0.5s/tile will soon transforms into much higher, 
transforming mapnik into unusable

Sounds like a corner case right ?

So, staying for now with my idea, is there some mecanism implemented (or to be 
implemented) in mapnik to :
- When a tile is empty, not try to generate it (use a defined png model 
instead), and not try to generate any other tiles included in zoom greater 
than it
- On each postgres "osm data update" ( with some kind of last-modified flag ?) 
use them to render only last modified zones, wich, to my point of vew seams 
to be much less numerous that vews
?

-- 
Sylvain Letuffe liste at letuffe.org
qui suis-je : http://slyserv.dyndns.org