[OSM-talk] Why isn't any XAPI server available ?
osm at petschge.de
Sat Feb 19 16:22:01 GMT 2011
> For simple map calls there is TRAPI. As far as I know, TRAPI performs
> much better on map (bbox) queries than either the main-API, XAPI or ROMA (on
> equivalent hardware). Rather than using a database, I think it used a
> pre-tiled file structure, so that it simple needs to peace together a bunch
> of tiles, rather than do a full search in a db, which massively reduced the
> disk seeks necessary.
You point out several points which are correct but not very well known.
TRAPI exists, feeds the tiles at home clients, uses a pre-tiled structure
directly in the file system and is rather fast. Not clue why it is
ignored so often.
> I don't think XAPI is all that much better suited for map requests than the
> main API and imho it was rather unfortunate that the mantra has been for
> people getting banned from the main API for scraping to use XAPI. This just
> bogged down XAPI for people who actually needed its extra capabilities.
Right and that is why the tiles at home clients talk to the TRAPI load
balancer instead of the XAPI. But to be honest most people scraping the
XAPI would be better served by using a planet dump or extract thereof
instead of arduous scraping a web service, be it XAPI or TRAPI. Actually
I have been thinking of creating a patch to jXAPI that answers every
large map call from an IP that has recently requested several other
large map calls with an empty OSM file containing a comment along the
lines of "hey you. don't bog down this server but grab an extract".
Patrick "Petschge" Kilian.
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