[postgis-devel] Optimizing contains/within

Robert W. Burgholzer rburghol at vt.edu
Mon Jul 23 13:53:21 PDT 2007

Thanks Charlie, I will check into Valgrind.


Quoting Charlie Savage <cfis at savagexi.com>:

> Hi Robert,
> > I am looking at the geos code for the contains calls for a point in a
> > multipolygon, which appears to boil down to the function:
> >
> > point_in_ring(POINTARRAY *pts, POINT2D *point)
> Have you profiled your program?  If not, then the first step it to
> figure out what is slow.  If you have access to a Linux box then run
> your program under Valgrind (it has a profiler) and it will tell you
> *exactly* what is slow.  In a large code base like GEOS, its almost
> impossible to know where the bottlenecks are by just eyeballing the
> code.  Just because a function is called a million times doesn't
> necessarily make it the bottleneck.
> Once you know which function, and which line is slow, then its becomes
> much easier to fix the problem.
> Charlie

Robert W. Burgholzer
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