... and I truly hope that whatever I found out is just my mistake,
already solved and not as terrible as it appears, so here it comes:
Whenever you make a call to maya.cmds.<commandname>, an arglist and a
your list of kwargs will be stored as tuples and held. These tuples
will never be collected or deleted, and thus consume memory.
This starts becoming an issue if you call a command a few 10 thousands
of times.
I could verify this issue on Maya8.5 64 linux and Maya2008 OSX.
I assume that someone in the c-part of the cmds wrap does not
decrement the refcount on the tuples created, thus python keeps
thinking they are in use. The refcount of these tuples 3(-1) in Maya
8.5 and 4(-1) in Maya2008.
Is this a known bug ? If not it would be great if anyone with a nice
support contract could bring it up :).
Cheers,
Sebastian ( being so incredibly disappointed right now )
The Code :
Makes 10 runs and calls simple mel commands 1000 times, checking the
garbage collectors object count after each run.
The collection cannot get ahold of these objects being continuously
added to the collector.
As these commands are read-only, the undo-queue cannot be involved.
If you rewrite the loop so that it uses the pymel API wrap for
instance, the gc's object count will not raise.
If you want to crank up the numbers, you will see that this really
consumes memory once the object count hits a million and if you issue
a little more complex commands.
<pre>
import sys
import gc
assert gc.isenabled()
import maya.cmds as cmds
for run in range( 10 ):
print "%i: Pre-cmds execution: %i" % ( run, len( gc.get_objects() ) )
for i in range( 1000 ):
cmds.listRelatives( "persp", shapes = 1, ni = 1 )
cmds.ls( sl=1 )
print "Post-cmds execution: %i" % len( gc.get_objects() )
# the garbage collection cannot get ahold of these objects
assert gc.collect() == 0
# lets check the refcount on these tuples
lobj = gc.get_objects()[-1]
print "%s.refcount = %i" % ( lobj, sys.getrefcount( lobj ) )
# just to be sure: yes, its our arguments we passed to the cmds
for obj in gc.get_objects()[-50:]: print obj
</pre>
--~--~---------~--~----~------------~-------~--~----~
http://groups.google.com/group/python_inside_maya
-~----------~----~----~----~------~----~------~--~---
