[OSM-dev] on-disk indexing of geodata

Freek freek_osm at vanwal.nl
Fri Oct 17 14:25:59 BST 2008

On Friday 17 October 2008, Sascha Silbe wrote:
> Actually it seems I've been limited in view by my own application. The
> problem I'd have with updating data isn't how to map data updates to
> tree updates (the topic covered by the paper mentioned above) but how to
> efficiently do inserts and deletes on an on-disk tree. 

Generally you keep a bit of free space in all nodes to accommodate a number of 
insertions and deletions, and only split or merge nodes when they overflow or 
underflow so that you don't need to move around all kinds of elements all the 

> I haven't done 
> any research on that topic, though, since I don't need it yet (bulk
> imports are quite fast - ~25 minutes for the 865MB europe.osm.bz2).

That's not bad, I suppose your index still fits in memory? I think that in 
most cases the top part of the tree should fit in memory and only the leaves 
(containing pointers/addresses to the actual items) will stay on disk during 


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