Significant memory leak in win32pdh.GetFormattedCounterArray()

[iglendd]

pywin32/win32/src/win32pdhmodule.cpp

Line 677 in 3a3e0e9

static PyObject *PyPdhGetFormattedCounterArray(PyObject *self, PyObject *args)

A script similar to the one below will leak a gigabyte memory per minute (due to tight loop of course). The leak appears to be caused by the fact of not releasing the key after it has been added to the dictionary which adds its own reference.

pywin32/win32/src/win32pdhmodule.cpp

Line 722 in 3a3e0e9

key = PyWinObject_FromTCHAR(pItems[i].szName);

It is worth noting that the function has an unrelated logical flaw - it currently cannot handle duplicate instance names (https://learn.microsoft.com/en-us/windows/win32/perfctrs/handling-duplicate-instance-names). Not sure how it should be addressed. Either creating a duplicate function (waste) or enhancing the function to have a value in the dictionary as formatted value or a list, when there is a duplicate instance (but it may break existing usage). On the other hand, due to very significant memory leak without prior reporting perhaps the function is not actively used and can be modified.

import win32pdh

# will generate path "\LogicalDisk(*)\Free Megabytes"
path = win32pdh.MakeCounterPath( (None, "LogicalDisk", "*", None, 0, "Free Megabytes")) 
win32pdh.ValidatePath(path)                          

hq = win32pdh.OpenQuery()                                       
hc = win32pdh.AddEnglishCounter(hq, path)                       

try:
   win32pdh.CollectQueryData(hq)                               
except Exception:
   pass

win32pdh.CollectQueryData(hq)                                  

while True:
   vals = win32pdh.GetFormattedCounterArray(hc, win32pdh.PDH_FMT_DOUBLE)

[mhammond]

Thanks - fixed in 1962631

[ofek]

Awesome! When might this be released?