Re: [Matplotlib-users] Memory leaks in a web application

[Gerry S. <ger...@gm...>]

Thanks Michael ,

I had somehow put myself under the impression i was using he OO
version of the api but it is much more clear now. Memory issues now
look better.

Thanks.

2009/2/10 Michael Droettboom <md...@st...>:
> This is an instance of the OP's problem again.  Your example is using the
> pyplot (i.e. Matlab-like) interface, in which case, you must explicitly
> close each figure when you're done with it, like follows:
>
>  plt.close(fig)
>
> "del fig" only deletes your local reference to the figure.  There is still a
> reference being held by the figure manager in case you wanted to go back to
> an earlier figure (accessed by number) and edit it.  This is essentially the
> price paid for Matlab-work-a-likeness.
>
> I've tested your script on 0.98.3 (though on a RHEL4 system) and I don't see
> any memory leaks after adding the call to "plt.close(fig)".
>
> If you instantiate the figure and canvas directly (as in the agg_oo.py
> example), you won't have this issue.
>
> Mike
>
> Gerry Steele wrote:
>>>>
>>>> instance of Figure(), then you shouldn't need to close the figure by
>>>> hand.
>>>> It should be deleted whenever you delete or replace your instance of
>>>> Figure.  (If I understand correctly.)
>>>>
>>
>>
>>>
>>> ... Garbage collection will take
>>> care of reclaiming memory once the user code has no more references to
>>> the object either.
>>>
>>
>>
>> I guess that is how it should work in theory. However at least for the
>> version of mpl shipped with ubuntu 8.10 (Version: 0.98.3-4ubuntu1)
>> there is surely quite a serious and easily demonstrated memory leak
>> using the artist api. Even if you manually del the figure objects
>> which are created inside a loop a significant growth of memory can be
>> observed. In fact I think there may be two separate leaks.
>>
>> In the attatched standalone code example after 1000 iterations
>> creating 1000 png graphs there is around 2GB of RAM consumed. If you
>> takeout the call to savefig around 600MB is consumed.
>>
>> In my view the code in the loop should execute in constant space
>> without growth at all. Note that when the function returns the memory
>> seems to be deallocated so if you check the ram use during the sleep
>> you should see this.
>>
>> Any ideas on this?
>>
>>
>>
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>
> --
> Michael Droettboom
> Science Software Branch
> Operations and Engineering Division
> Space Telescope Science Institute
> Operated by AURA for NASA
>
>



-- 
Gerry Steele
http://belfast.no-ip.info/