A very abridged example of what was originally a major leak

{Animator[Dynamic@α, RefreshRate -> 120],
 Dynamic[arrows = (α; Arrow[{{0, 0}, {0., 1} + 0.001 RandomReal[2, 2]}]);],
 Dynamic[Graphics[arrows, ImageSize -> Tiny]

I'm running Windows 7, x64, Mathematica 8.0.4. The Mathematica.exe process slowly (in this example) grows in memory usage and nothing I tried other than close and reopen Mathematica, seems to help.

Can you reproduce the problem? Is it known? What exactly is causing it? Any way to handle it?

I haven't got much experience in interfaces, but I had done a satisfactory one only to realise after a while it was using up 1.5GB of RAM

  • $\begingroup$ How fast is the memory leaking on your machine for this example? I see something like 0.5 MB increase in memory/10 mins of running. $\endgroup$
    – rm -rf
    May 30, 2012 at 4:15
  • $\begingroup$ Ok, it gets faster at some point. Now it's at 250 MB after 1 hr. 8.04 on MacOSX. $\endgroup$
    – rm -rf
    May 30, 2012 at 5:16
  • $\begingroup$ Confirmed on version 7 under Windows 7. It is significantly worse with Animator[Dynamic@α, RefreshRate -> 120] $\endgroup$
    – Mr.Wizard
    May 30, 2012 at 5:30
  • $\begingroup$ Confirmed here too. Windows7-64, MMA 8.04. There's indeed a speed-up after some time. I'd say I lose about 1 MB/s (using Mr.Wizard's setting). $\endgroup$ May 30, 2012 at 10:43
  • $\begingroup$ This looks like a multi-platform/multi-version bug indeed. Could you report this to [email protected]? $\endgroup$ May 30, 2012 at 10:48

2 Answers 2


Reported, and forwarded to the developers. It is still there in v9


It seems like it's the Graphics[arrows] part. This:

{Animator[Dynamic@\[Alpha], RefreshRate -> 120], 
 Dynamic[arrows = (\[Alpha]; 
     Arrow[{{0, 0}, {0., 1} + 0.001 RandomReal[2, 2]}]);], 

Does not produce a memory leak for me: MMA 8.0.0 on Win7-64. Is it possible it is a history / Out[] type problem?

  • $\begingroup$ I still get a memory leak with this but it's a slow one. I suppose it's related to this one where each unique object created is cached somehow. $\endgroup$
    – Mr.Wizard
    May 30, 2012 at 17:50
  • $\begingroup$ I even get a slow leak with {Animator[Dynamic@\[Alpha], RefreshRate -> 120], Dynamic[arrows = (\[Alpha]; Arrow[{{0, 0}, {0., 1}}]);], Dynamic[Null]} so there is perhaps a separate leak even without unique objects. $\endgroup$
    – Mr.Wizard
    May 30, 2012 at 17:53

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