[mkgmap-dev] Memory limits for mkgmap and splitter

Wed Aug 5 21:17:09 BST 2009

> Can you please tell me exactly what parameters you used to run both the
> old
> and the new splitters to get your results? Would it be possible to get
> hold
> of the osm file you used to run your test against? I'd be interested in
> replicating
> the poor performance so I can try to fix it.

Hi Chris,

I have run my tests on another machine (my first tests were made with a
notebook with virus scanner, harddisk encryption ...): 
old splitter ( 51922 bytes): 196s
new splitter (181951 bytes): 213s

This is nearly the same performance (+8%).

Windows XP SP2 32Bit, Java 1.6.0_15
Athlon 64 X2 4600+, 2 GB RAM
No virus scanner, no harddisk encryption

Data:
http://download.geofabrik.de/osm/europe/germany/bayern.osm.bz2

I've unzipped the file and called the splitter with these parameters:

java -Xmx1400M -ea -jar splitter.jar --mapid=1 --max-nodes=800000 bayern.osm

I also made some tests with long ways in germany. With max-nodes 800000 I
have 3 ways in more than 4 tiles, but they are not important (Oberpfalz
polygons). With max-nodes 400000 I get 12 ways: 2 rivers (Rhein, Mosel), 5
power lines and some unimportant ways.

So if I do not use low max-nodes values I have no urgent problem with long
ways in germany. Thanks for solving the 4 tiles restriction of relations,
this was more important! 

Rudi