I've run across a memory leak in a long running process which I can't
determine if its my issue or if its the logger.
The long and short is I'm doing load testing on an application server
which spawns handlers threads which in turn each spawn a single
application thread. A graphic representation would be One Server ->
(to many pairs of) [ Handler <-> Application ].
Each application thread gets a logger instance in it's init() method
via:
self.logger = logging.getLogger('ivr-'+str(self.rand))
where self.rand is a suitably large random number to avoid collisions
of the log file's name. Until the log file gets created I attach am
memory handler
self.memhandler =
logging.handlers.MemoryHandler(1000)
self.memhandler.setLevel(10)
formatter = logging.Formatter('%
(levelname)s %(message)s')
self.memhandler.setFormatter(formatter)
self.logger.addHandler(self.memhandler)
when the application thread formally starts with the run() method I
create the log file and terminate the memory handler
filehandler = logging.FileHandler(logfilename)
filehandler.setLevel(10)
formatter = logging.Formatter('%(levelname)s %(message)s')
filehandler.setFormatter(formatter)
self.memhandler.setTarget(filehandler)
self.memhandler.close()
self.logger.removeHandler(self.memhandler)
self.logger.addHandler(filehandler)
finally the last statements in the run() method are:
filehandler.close()
self.logger.removeHandler(filehandler)
del self.logger #this was added to try and force a clean up of
the logger instances.
Using the objgraph to look at the objects in memory I find the number
of logger instances equal to the total number of threads to have lived
despite the fact that either a) there are only the standard load
testing number of threads alive, 35 or b) that there no threads
running nor are there any stale waiting for the GC.
>From objgraph a selection of the most prevalent objects in memory are
(this is with the system idle post-run):
list 256730
dict 128933
Logger 128164 # total
application threads executed running load testing.
function 2356
wrapper_descriptor 1028
builtin_function_or_method 702
method_descriptor 648
tuple 643
weakref 629
getset_descriptor 304
type 252
set 224
member_descriptor 209
module 128
WeakSet 102
The only references to self.logger other than those listed are wrapper
methods defined in the application thread to wrap up the log / debug
methods. Any help or direction would be much appreciated.
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