Overpass API developpement

[QUILLET Jean-Charles <>]

Hello,

For the project I'm working on, I need to be able to download a big amount of OSM data from a user specified bounding box. As the public servers do not allow me to do that, I've set up a server following the instructions on the wiki. It's working great so far but I find it difficult to understand how the resource management is working.

According to the wiki: http://wiki.openstreetmap.org/wiki/Overpass_API#Resource_management_options_.28osm-script.29

"These resource limits (max size and timeout) cannot be set to arbitrary high values: each Overpass API instance may refuse to extend them above some threshold (depending on server capabilities or current server load), or the query may just fail with an error message (and non-OK HTTP server error status)."

Indeed, I've found out when I send a maxsize over 5Go in my request, the serveur returns an error (somehow kind of confusing, as it says that the server is overcrowded, but it's not). When I use 4Go as maxsize, it's working fine.

How is the maximum allowed size actually computed ?

Thanks,

Jean-Charles