[OSM-dev] Osmosis multi-task questions

[Lambertus]

Martijn van Oosterhout wrote:
> On Nov 27, 2007 4:37 PM, Lambertus <osm at na1400.info> wrote:
>> My tests reveal:
>> Extracting bounding boxes one-by-one from the planet file uses: tN.
>> Where 't' is the time to extract one bbox, 'N' is the amount of bboxes.
>>
>> Extracting multiple bboxes from the planet file using 'tee' takes less
>> then: 2t. Where 't' is the time to extract one bbox.
> 
> Interesting. Probably memory usage the goes linear by N but that's a
> smaller problem...

No. BrettH has gone to great lengths just to prevent that:

[quote=BrettH]
I've written a new internal id store for use with area filtering tasks 
(ie. bounding box and polygon) and want to see if the memory usage is 
any lower.  The new one stores ids as 32 bit ints instead of a single 
bit but it only stores the ids that are selected instead of every id in 
the planet so if the bounding box contains less than 1/32 of the total 
planet data it should use less memory ... in theory.
[/quote]