Set x to to None and del x doesn't release memory in python 2.7.1 (HPUX 11.23, ia64)

[Wong Wah Meng-R32813]

Hello there,

I am using python 2.7.1 built on HP-11.23 a Itanium 64 bit box. 

I discovered following behavior whereby the python process doesn't seem to release memory utilized even after a variable is set to None, and "deleted". I use glance tool to monitor the memory utilized by this process. Obviously after the for loop is executed, the memory used by this process has hiked to a few MB. However, after "del" is executed to both I and str variables, the memory of that process still stays at where it was. 

Any idea why?

>>> for i in range(100000L):
...     str=str+"%s"%(i,) 
... 
>>> i=None
>>> str=None
>>> del i
>>> del str