[Maps-l] ptolemy performance

[Tim Alder]

Thomas Ineichen schrieb:
> Looking at Zoom 12:
> http://www.openstreetmap.org/?lat=49.4592&lon=10.9644&zoom=12&layers=M
> 
> Do we really need a weekly update on that zoom? What you can see is:
> - main streets (secondary and up) and trains
> - forests and fields
> - names of villages and cities
> 
> IMHO those things don't change often enough to let them jam the queue.
> Rendering them once a month would be ok.
> 
I think in countries like Germany there will be not often such large 
changes in this zoom level, but I believe in other areas it's possible 
to be the first mapper on a motorway. So this differences should we have 
in mind but I believe a montly update should be enough for this 
zoom-levels. We can adjust it so that the server has enough to do.
For the database I'm glad that we have updates each minute because we 
use this database also for other tools.
> 
> Secondly:
> Is  it  correct,  that  tiles  never  get  deleted? So every tile gets
> rerendered  according  to the timetable, no matter if it was requested
> from  a  user  during that period or not? So maybe a deletion strategy
> would be handy..
> 
It's true that we not deleting tiles in the moment. This seems only 
necessary if the harddisks will be nearly full (In the moment we use 68% 
of the /osm-space[1]). So we have some months to think about a good 
strategy.
If necessary, I would delete rare used z=16-18 tiles (reasons: cheap to 
render, a lot of tiles, improbable that somebody else need it).



[1]http://munin.toolserver.org/OSM/ptolemy/df.html