Find out how much memory is being used by an object in Python

Question

How would you go about finding out how much memory is being used by an object  I know it is possible to find out how much is used by a block of code  but not by an instantiated object  anytime during its life   which is what I want

User · Answer

This must be used with care because an override on the objects __sizeof__ might be misleading.

Using the bregman.suite, some tests with sys.getsizeof output a copy of an array object (data) in an object instance as being bigger than the object itself (mfcc).

>>> mfcc = MelFrequencyCepstrum(filepath, params)
>>> data = mfcc.X[:]
>>> sys.getsizeof(mfcc)
64
>>> sys.getsizeof(mfcc.X)
>>>80
>>> sys.getsizeof(data)
80
>>> mfcc
<bregman.features.MelFrequencyCepstrum object at 0x104ad3e90>

User · Answer

There s no easy way to find out the memory size of a python object  One of the problems you may find is that Python objects - like lists and dicts - may have references to other python objects  in this case  what would your size be  The size containing the size of each object or not    There are some pointers overhead and internal structures related to object types and garbage collection  Finally  some python objects have non-obvious behaviors  For instance  lists reserve space for more objects than they have  most of the time  dicts are even more complicated since they can operate in different ways  they have a different implementation for small number of keys and sometimes they over allocate entries    There is a big chunk of code  and an updated big chunk of code  out there to try to best approximate the size of a python object in memory    You may also want to check some old description about PyObject  the internal C struct that represents virtually all python objects

User · Answer

For big objects you may use a somewhat crude but effective method  check how much memory your Python process occupies in the system  then delete the object and compare   This method has many drawbacks but it will give you a very fast estimate for very big objects

User · Answer

Try this  sys getsizeof object   getsizeof   Return the size of an object in bytes  It calls the object   s   sizeof   method and adds an additional garbage collector overhead if the object is managed by the garbage collector  A recursive recipe

User · Answer

Another approach is to use pickle  See this answer to a duplicate of this question

User · Answer

I haven t any personal experience with either of the following  but a simple search for a  Python  memory  profiler  yield    PySizer   a memory profiler for Python   found at http   pysizer 8325 org    However the page seems to indicate that the project hasn t been updated for a while  and refers to    Heapy   support ing  debugging and optimization regarding memory related issues in Python programs   found at http   guppy-pe sourceforge net  Heapy    Hope that helps

[python] Find out how much memory is being used by an object in Python

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