[mkgmap-dev] Possible memory reduction in mkgmap

Thu Jan 10 18:38:09 GMT 2013

> Hi,
>
> it is easy to change the HashMap<Long,Coord> coordMap in  ElementSaver
> to use the OSMId2ObjectMap that I've implemented for splitter.
> This could reduce peak memory usage in mkgmap.
>
> A few numbers according to VisualVM:
> 2.248.404  coord instances managed in the HashMap  req. 186.447.135 bytes,
> with OSMId2ObjectMap it is 57.194.684.
> This doesn't include the memory that is needed to store the Coord instances
> itself,
> (which I think is 2.248.404 * 32 = 71.948.928 bytes)
> it is just the overhead for the map.
>
> The disadvantage: OSMId2ObjectMap uses fastutil.jar, which is not used in
> mkgmap
> until now. I could try to change OSMId2ObjectMap so that it runs without
> fastutil.jar,
> but that would mean to invent the wheel again.
>
> Comments?
>
> Gerd
>

Sounds good.
I think it's ok to add the fastutil.jar to mkgmap.

WanMil