On 19-Jun-09, at 8:54 PM, Hamish wrote:
Michael wrote:
I actually get the same thing.
For the first while the process runs in full use
of one core, but once the process starts writing results to
the db, the whole process bogs down to a
grinding halt. CPU usage for v.lidar.edgedetection
drops down to ~1% (1% of one core) and sqlite usage rises to
~16%. Maybe I'm wrong, but my impression was that the
bottle neck was the modifications to the database.
hmmm. I've seen no problems on Linux64 + DBF backend. 100% core until
completion.
Are you running WinXP + SQlite? Can you try with the DBF driver?
maybe the common problem is in the SQLite driver... ??
I'm running Mac OS X + SQLite with a 64 bit version of grass. I ran a
whole bunch of tests today and it looks like there are at least a
couple of things going on and SQLite is one of the issues. I ran a
500m x500m tile with three different DB back-ends (SQLite, Postgres
and DBF) and these are the results I obtained;
(SQLite)
time v.lidar.edgedetection input=Cal_QTile output=Cal_QTile_edges
real 38m53.458s
user 1m17.602s
sys 4m6.353s
(Postgres)
time v.lidar.edgedetection input=Cal_QTile output=Cal_QTile_edges
real 6m49.060s
user 0m46.622s
sys 1m20.324s
(DBF)
time v.lidar.edgedetection input=Cal_QTile output=Cal_QTile_edges
real 1m54.065s
user 0m48.530s
sys 1m8.686s
The results with Postgres and SQLite were a real surprise to me.
if you build from the latest grass 6.5 or 7 svn you can use the --
verbose
flag to follow the action. setting 'g.gisenv set="DEBUG=1" gives you
even more detail (even with existing versions).
Does this print out the debugging messages that are in the code or do
I need to do something else to see those?
please create your patches with "svn diff > somepatch.diff" and file
them
in the trac system. Otherwise they quickly get lost and forgotten.
http://grass.osgeo.org/bugtracking/
https://trac.osgeo.org/grass/wiki/WikiStart#BugTracking
OK, thanks. I'll post a bug report and submit a patch soon.
Cheers,
Mike
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