Help on slow attribute copy

[bgs]

There's no way that loop takes fifteen minutes just because of the dot
operator.  I mean, 200000 dots in 15 minutes is 200 dots/second.  On a
1 GHz machine, that would be 5 million cycles per dot.   That does not
seem reasonable (assuming you haven't overridden the dot operator to do
something more complicated than normal).

Check that i.label does not have __hash__ overridden in a bad way.  I
tried a test case with __hash__ overridden to always return the same
integer, and I got performance about what you are describing when I
tried your example loop with 100000 iterations.

And, of course, make sure you are not low on memory and relying too
heavily on swap space.