Report LabVIEW2025 Q3 BUG about python node

[Wlison]

I found that 'Open Python Session' causes a memory leak. Can anyone help me solve this problem?

[Jay14159265]

Does it do the same in a loop? 

[Jay14159265]

Does this leak 5 references or 1? 

[Wlison]

Yes, it's the same in a loop; every time the loop runs, there will be a memory leak.

[Jay14159265 · Accepted solution]

---

@Wlison wrote:

Yes, it's the same in a loop; every time the loop runs, there will be a memory leak.

---

Hmm, under the hood LV has to launch a python interpreter instance and link to it. Not sure the details of how NI does that but I wonder if the external reference is the detected leak. 

Without solving the issue of NI trace detecting a leak, perhaps you can code around it by only calling Open Python Session once for the lifetime of the LV app. Unless you really need multiple python interpreters its probably faster code to launch one and keep it open rather than spinning one up each time you need it. 

[Wlison]

It seems that there is no way to solve this problem, because calling the Python node will also cause a memory leak.

[rolfk · Accepted solution]

Jay wasn't talking about solving the problem but about mitigating it. Rather than open a new Python session over and over again, only do it once and then reuse it throughout the application lifetime.

Are you implying that every time the Call Python node is called it creates yet another memory leak?

[Wlison]

Yes, in certain situations it can lead to memory leaks.