Michiel de Hoon wrote: > Hi everybody, > > I was looking at this bug about a memory leak: > > https://sourceforge.net/tracker/?func=detail&atid=560720&aid=2889570&group_id=80706 > > While this bug is now essentially fixed, I noticed that the Figure class > contains some circular references that prevent it from being cleaned up by > the garbage collector, which is effectively a memory leak. At least, for this > code: > >>>> from matplotlib.figure import Figure >>>> fig = Figure() >>>> del fig > > the garbage collector reports 76 unreachable objects. This seems to be > independent of which backend is being used. > > Is it worthwhile to look deeper into it? Or should we accept that it is > unavoidable that a library of the size of matplotlib will have circular > references? >
The purpose of the garbage collector is to handle the case of circular references--and mpl is full of circular references. When there are no circular references, then reference counting suffices. The garbage collector fails to handle circular references when an object has a __del__ method. I don't think we have that problem. I am not actually seeing the result you describe, though. Using python from the interactive prompt--no ipython--when I do gc.collect() and then gc.get_count() I get back to the count from before instantiating the Figure. >>> gc.get_count() (4, 0, 0) >>> gc.get_count() (5, 0, 0) >>> gc.get_count() (5, 0, 0) >>> gc.get_count() (5, 0, 0) >>> fig = Figure() >>> gc.get_count() (128, 0, 0) >>> del(fig) >>> gc.get_count() (128, 0, 0) >>> gc.collect() 76 >>> gc.get_count() (4, 0, 0) >>> gc.get_count() (5, 0, 0) Eric > > --Michiel. > ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
