[Matplotlib-users] hist() memory leak?

[Luke R. <luk...@gm...>]

I'm writing a program that processes ~ 25,000 jobs and each iteration
draws a histogram and writes out some of the output.  I let it run all
night and when I came back, python was filling up all my memory
(2Gigs) and was thrashing on and off of swap.  I narrowed the problem
down to my calling of the hist() function, and was able to reproduce
it in the following code I copied from the mpl website.

Am I not properly closing the figure somehow?
Has this issue already been addressed?

I recently installed version 0.90.1 of matplotlib, although I don't
see any easy way to verify that version number from within python.

-Luke Robison


Code:
-------------------
import os,time,sys
from pylab import *

def report_memory(i):
    pid = os.getpid()
    a2 = os.popen('ps -p %d -o rss,sz' % pid).readlines()
    print i, '  ', a2[1],
    return int(a2[1].split()[1])

# take a memory snapshot on indStart and compare it with indEnd
indStart, indEnd = 100, 150
for i in range(indStart,indEnd):
    ind = arange(100)
    xx = rand(len(ind))

    figure(1)
    hist(xx)
    close(1)

# wait a few cycles for memory usage to stabilize
    if i==indStart: start = val
    if i>indStart:
        end = val
        print 'Average memory consumed per loop: %1.4fk bytes' % \
              ((end-start)/float(indEnd-indStart))

-----------------

Output:


python memtest.py

Average memory consumed per loop: 0.0000k bytes
102    39808 21991
Average memory consumed per loop: 0.0000k bytes
103    39828 21991
Average memory consumed per loop: 0.0000k bytes
104    39852 22024
Average memory consumed per loop: 0.6600k bytes
105    39876 22024
Average memory consumed per loop: 0.6600k bytes
106    39908 22024
Average memory consumed per loop: 0.6600k bytes
107    39932 22024
Average memory consumed per loop: 0.6600k bytes
108    39960 22024
Average memory consumed per loop: 0.6600k bytes
109    39980 22057
Average memory consumed per loop: 1.3200k bytes
110    40008 22057
Average memory consumed per loop: 1.3200k bytes
111    40032 22057
Average memory consumed per loop: 1.3200k bytes
112    40056 22057
Average memory consumed per loop: 1.3200k bytes
113    40084 22057
Average memory consumed per loop: 1.3200k bytes
114    40104 22090
Average memory consumed per loop: 1.9800k bytes
115    40132 22090
Average memory consumed per loop: 1.9800k bytes
116    40156 22090
Average memory consumed per loop: 1.9800k bytes
117    40180 22090
Average memory consumed per loop: 1.9800k bytes
118    40208 22090
Average memory consumed per loop: 1.9800k bytes
119    40232 22123
Average memory consumed per loop: 2.6400k bytes
120    40256 22123
Average memory consumed per loop: 2.6400k bytes
121    40280 22123
Average memory consumed per loop: 2.6400k bytes
122    40304 22123
Average memory consumed per loop: 2.6400k bytes
123    40328 22123
Average memory consumed per loop: 2.6400k bytes
124    40356 22123
Average memory consumed per loop: 2.6400k bytes
125    40380 22156
Average memory consumed per loop: 3.3000k bytes
126    40404 22156
Average memory consumed per loop: 3.3000k bytes
127    40428 22156
Average memory consumed per loop: 3.3000k bytes
128    40452 22156
Average memory consumed per loop: 3.3000k bytes
129    40476 22156
Average memory consumed per loop: 3.3000k bytes
130    40500 22189
Average memory consumed per loop: 3.9600k bytes
131    40528 22189
Average memory consumed per loop: 3.9600k bytes
132    40548 22189
Average memory consumed per loop: 3.9600k bytes
133    40576 22189
Average memory consumed per loop: 3.9600k bytes
134    40596 22189
Average memory consumed per loop: 3.9600k bytes
135    40624 22222
Average memory consumed per loop: 4.6200k bytes
136    40652 22222
Average memory consumed per loop: 4.6200k bytes
137    40676 22222
Average memory consumed per loop: 4.6200k bytes
138    40700 22222
Average memory consumed per loop: 4.6200k bytes
139    40724 22222
Average memory consumed per loop: 4.6200k bytes
140    40744 22222
Average memory consumed per loop: 4.6200k bytes
141    40768 22255
Average memory consumed per loop: 5.2800k bytes
142    40800 22255
Average memory consumed per loop: 5.2800k bytes
143    40824 22255
Average memory consumed per loop: 5.2800k bytes
144    40848 22255
Average memory consumed per loop: 5.2800k bytes
145    40872 22255
Average memory consumed per loop: 5.2800k bytes
146    40896 22288
Average memory consumed per loop: 5.9400k bytes
147    40916 22288
Average memory consumed per loop: 5.9400k bytes
148    40940 22288
Average memory consumed per loop: 5.9400k bytes
149    40972 22288
Average memory consumed per loop: 5.9400k bytes


as you can see, the memory consumption is increasing each loop, and
furthermore, and an increasing rate :-(