Memory leaks in MEL

[augie]

I’ve run into a huge problem with just about every large MEL script I’ve written in the last couple of years. I tend to build tools in Maya to help me with tasks such as laying out navigation meshes in a game level or exporting vertex colors from hundreds of meshes to a binary file. When running these large MEL scripts, I always end up seeing Maya’s memory usage expand as the script runs until eventually Maya runs out of memory and crashes. I was using the 32-bit version, but ended up having to go to the 64-bit version because these scripts eventually cause maya to grow beyond the 4GB limit. Well, even the 64-bit version isn’t a big enough band-aid to fix this problem. Maya’s currently at 9.4GB right now after having loaded 43,185 path nodes from tiny 3.2 MB a binary file. Maya never releases the memory until it’s quit and re-opened.

I really don’t know where these memory leaks are coming from. I’ve tried and tried to debug my code in the past to find the sources but I always end up having leaks galore anyway. The most common culprit seemed to be not clearing arrays after using them, but I’ve been very careful to always do that. Also, I have the undo buffer disabled and am going to the extra effort to flush the buffer anyway. History is off as well. I’m out of ideas on where to look.

It’s really becoming a productivity killer.

[joojaa]

that would most likely still be the undo. Possibly tough a global variable. Mel does not really noticeably leak for me but maya allways had problems with very big scenes.

Anyway you dont give anything to work on. So ill just assume its you thats the problem with lack of contrary evidence.

Try saving the scene and see what the delta is. Then running the script without creating nodes.

[augie]

that would most likely still be the undo. Possibly tough a global variable. Mel does not really noticeably leak for me but maya allways had problems with very big scenes. Anyway you dont give anything to work on. So ill just assume its you thats the problem with lack of contrary evidence. Try saving the scene and see what the delta is. Then running the script without creating nodes.

Sample MEL file and binaries (Zip)
Just the MEL file (txt)

I've included a link to a zip file containing the loading portion of my MEL script responsible for loading the path nodes into Maya. (I left out the UI, the saving, the editing tools, etc.) Note that the path nodes aren't meant to be saved in a scene. Rather this is part of a path node editing system and the nodes would be saved out to a binary file. To load a binary, first edit line 16 in the MEL file and change the path to the binary to load, then just copy and paste the entire script into Maya.

I tried commenting out the code that actually creates the node objects (and the conneciton objects) and the expansion of memory is much much slower ... about +1 MB per run. So the memory expansion definitely has to do with the creation of the new objects in the Maya scene. My nodes are simple pyramid shapes with 5 verts. My connections between nodes are equally simple 6 vertex extruded triangles. When a node is created in the world, it duplicates the master node and moves it to position. When a connection is loaded, it duplicates the master connection and stretches it into place to fit between the nodes its connecting.

I included two binary files in the zip file which contain path node and connection data. If you load the smaller binary file, Maya should only bloat up to < 2GB I believe. If you load the larger one, it will go up to around 9GB.