correction of mem leak of django + apache

The code below consume large memory and don't return.
Apache process memory will keep increasing with the code below.

aaa = data.objects.all().order_by('-id')
count_of_aaa = len(aaa)

The problem is "len(aaa)". (dunno why)
It should be replace by ...

count_of_aaa = aaa.count()

Then no mem leak occur.