Python: garbage collection fails? -

consider following script:

l = [i in range(int(1e8))] l = [] import gc gc.collect() # 0 gc.get_referrers(l) # [{'__builtins__': <module '__builtin__' (built-in)>, 'l': [], '__package__': none, 'i': 99999999, 'gc': <module 'gc' (built-in)>, '__name__': '__main__', '__doc__': none}] del l gc.collect() # 0 

the point is, after these steps memory usage of python process around 30 % on machine (python 2.6.5, more details on request?). here's excerpt of output of top:

 pid user      pr  ni  virt  res  shr s %cpu %mem    time+  command   5478 moooeeeep 20   0 2397m 2.3g 3428 s    0 29.8   0:09.15 ipython   

resp. ps aux:

moooeeeep 5478  1.0 29.7 2454720 2413516 pts/2 s+   12:39   0:09 /usr/bin/python /usr/bin/ipython gctest.py 

according the docs gc.collect:

not items in free lists may freed due particular implementation, in particular int , float.

does mean, if (temporarily) need large number of different int or float numbers, need export c/c++ because python gc fails release memory?

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update

probably interpreter blame, this article suggests:

it’s you’ve created 5 million integers simultaneously alive, , each int object consumes 12 bytes. “for speed”, python maintains internal free list integer objects. unfortunately, free list both immortal , unbounded in size. floats use immortal & unbounded free list.

the problem remains, cannot avoid amount of data (timestamp/value pairs external source). forced drop python , go c/c++ ?

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update 2

probably it's indeed case, python implementation causes problem. found this answer conclusively explaining issue , possible workaround.

i've done few tests, , issue occurs cpython 2.x. issue gone in cpython 3.2.2 (it drops memory usage of fresh interpreter) , pypy 1.8 (python 2.7.2) drops down same level new pypy process.

so no, don't need switch language. however, there's solution won't force switch different python implementation.