Closure saving and GC example. # needs memory_profiler module! $ python -m memory_profiler noleaks.py

noleaks.py

#!/usr/bin/env python2.7


import gc


def iterjam():
    import functools as ft

    def iterjam2():
        return ft

    return iterjam2


@profile
def main():
    horrible_things_might_happen = {}
    for number in xrange(1000000):
        horrible_things_might_happen[str(number)] = iterjam()

    print "1MM import closures saved"

    for number in xrange(500000):
        del horrible_things_might_happen[str(number)]

    print ".5MM import closures deleted"

    gc.collect()
    print "Collected memory"

    for number in xrange(500000, 1000000):
        del horrible_things_might_happen[str(number)]

    print ".5MM import closures deleted"

    gc.collect()
    print "Collected memory"

    horrible_things_might_happen = None

    print "Nullified closure container"

    gc.collect()
    print "Collected memory"

    del horrible_things_might_happen

    print "Deleted closure container"

    gc.collect()
    print "Collected memory"
    
    horrible_things_might_happen = {}
    for number in xrange(1000000):
        horrible_things_might_happen[str(number)] = iterjam()

    print "1MM import closures saved again"


if __name__ == '__main__':
    main()

output.txt

1MM import closures saved
.5MM import closures deleted
Collected memory
.5MM import closures deleted
Collected memory
Nullified closure container
Collected memory
Deleted closure container
Collected memory
1MM import closures saved again
Filename: noleaks.py

Line #    Mem usage    Increment   Line Contents
================================================
    16                             @profile
    17     8.633 MB     0.000 MB   def main():
    18     8.633 MB     0.000 MB       horrible_things_might_happen = {}
    19   421.363 MB   412.730 MB       for number in xrange(1000000):
    20   421.363 MB     0.000 MB           horrible_things_might_happen[str(number)] = iterjam()
    21
    22   421.363 MB     0.000 MB       print "1MM import closures saved"
    23
    24   422.215 MB     0.852 MB       for number in xrange(500000):
    25   286.961 MB  -135.254 MB           del horrible_things_might_happen[str(number)]
    26
    27   286.961 MB     0.000 MB       print ".5MM import closures deleted"
    28
    29   299.824 MB    12.863 MB       gc.collect()
    30   299.824 MB     0.000 MB       print "Collected memory"
    31
    32   299.992 MB     0.168 MB       for number in xrange(500000, 1000000):
    33   190.410 MB  -109.582 MB           del horrible_things_might_happen[str(number)]
    34
    35   190.410 MB     0.000 MB       print ".5MM import closures deleted"
    36
    37   190.031 MB    -0.379 MB       gc.collect()
    38   190.031 MB     0.000 MB       print "Collected memory"
    39
    40   189.781 MB    -0.250 MB       horrible_things_might_happen = None
    41
    42   189.781 MB     0.000 MB       print "Nullified closure container"
    43
    44   189.781 MB     0.000 MB       gc.collect()
    45   189.781 MB     0.000 MB       print "Collected memory"
    46
    47   189.781 MB     0.000 MB       del horrible_things_might_happen
    48
    49   189.781 MB     0.000 MB       print "Deleted closure container"
    50
    51   189.781 MB     0.000 MB       gc.collect()
    52   189.781 MB     0.000 MB       print "Collected memory"
    53
    54   189.781 MB     0.000 MB       horrible_things_might_happen = {}
    55   557.574 MB   367.793 MB       for number in xrange(1000000):
    56   557.574 MB     0.000 MB           horrible_things_might_happen[str(number)] = iterjam()
    57
    58   557.574 MB     0.000 MB       print "1MM import closures saved again"