为什么我用这个python循环泄漏内存？

我正在编写一个自定义文件系统爬虫,它通过sys.stdin传递数百万个glob进行处理.我发现在运行脚本时,它的内存使用量随着时间的推移而大量增加,整个事情几乎停止了.我在下面写了一个小例子来说明问题所在.我做错了什么,或者我在Python/glob模块中发现了一个错误？(我使用的是python 2.5.2).

#!/usr/bin/env python
import glob
import sys
import gc

previous_num_objects = 0

for count, line in enumerate(sys.stdin):
   glob_result = glob.glob(line.rstrip('\n'))
   current_num_objects = len(gc.get_objects())
   new_objects = current_num_objects - previous_num_objects

   print "(%d) This: %d, New: %d, Garbage: %d, Collection Counts: %s"\
 % (count, current_num_objects, new_objects, len(gc.garbage), gc.get_count())
   previous_num_objects = current_num_objects

输出如下:

(0) This: 4042, New: 4042, Python Garbage: 0, Python Collection Counts: (660, 5, 0)
(1) This: 4061, New: 19, Python Garbage: 0, Python Collection Counts: (90, 6, 0)
(2) This: 4064, New: 3, Python Garbage: 0, Python Collection Counts: (127, 6, 0)
(3) This: 4067, New: 3, Python Garbage: 0, Python Collection Counts: (130, 6, 0)
(4) This: 4070, New: 3, Python Garbage: 0, Python Collection Counts: (133, 6, 0)
(5) This: 4073, New: 3, Python Garbage: 0, Python Collection Counts: (136, 6, 0)
(6) This: 4076, New: 3, Python Garbage: 0, Python Collection Counts: (139, 6, 0)
(7) This: 4079, New: 3, Python Garbage: 0, Python Collection Counts: (142, 6, 0)
(8) This: 4082, New: 3, Python Garbage: 0, Python Collection Counts: (145, 6, 0)
(9) This: 4085, New: 3, Python Garbage: 0, Python Collection Counts: (148, 6, 0)

每100次迭代,释放100个对象,因此len(gc.get_objects()每100次迭代增加200个.len(gc.garbage)永远不会从0变化.第2代收集计数缓慢增加,而第0和第1计数上下变化.

我将其跟踪到fnmatch模块.glob.glob调用fnmatch实际执行globbing,而fnmatch有一个正则表达式的缓存,永远不会被清除.因此,在这种用法中,缓存不断增长且未经检查.我已经针对fnmatch库提交了一个错误[1].

[1]:http://bugs.python.org/issue7846 Python Bug