[Zope-dev] debugging memory leaks

[Barry Pederson]

Seb Bacon wrote:

> So, say Foo is leaking because it is referenced from O which can't be 
> collected.  Given 100 things which refer to Foo, how do I identify which 
> one is O?  And of course, then O may be leaking because it is referenced 
> from P...

I've been looking into memory leaks of my own, and put together a small 
module that outputs the information available from the gc.garbage list in a 
format that Graphviz (http://www.research.att.com/sw/tools/graphviz/) can 
then render as an image (GIF, SVG, etc) that makes it a bit easier to see the 
cycles.

Here's a sample image:

    http://barryp.org/misc/simpletal_visualize/test2.gif

Here's the code

     http://barryp.org/misc/simpletal_visualize/visualize_pyobjects.py

It shouldn't be too hard to use that in your own code, something like:

   import visualize_pyobjects
   gc.collect()
   cycles = visualize_pyobjects.prune_stems(gc.garbage)
   visualize_pyobjects.create_dot(cycles, '/tmp/foo.dot')

and then, run the graphviz 'dot' program from the command line to create a 
GIF file:

   dot -Tgif </tmp/foo.dot >/tmp/foo.gif

(use a '-Tsvg' option to create an SVG file, which is smaller and easily 
viewed and edited with things like sodipodi I believe)

	Barry