Question: Detecting memory leak by monitoring ReadMemStats

Hello fellow gophers!

I have a question regarding detecting memory leaks. There is an idea of detecting potential memory leak by monitoring memory. I have implemented a demo that runs a program and in a separate goroutine records runtime.MemStats. Currently, I just look at HeapAlloc every record and then try to seek out the pattern when there is a simulated memory leak. The simulated memory leak that I chose is to open 100000 times one file in a loop but leave it open. It accumulates 1MB approximately from storing file handlers.

I thought that HeapAlloc or HeapInuse or StackInuse would increase as the simulated memory leak accumulates more memory. But it is not the case, unfortunately.

Thanks for you attention!

Hi, @Highzest, and welcome to the forum!

I’m unclear on what you’re question actually is; are you asking why HeapAlloc or HeapInuse or StackInuse didn’t show what you want? Or what you should use instead? Both?

Yes, both. I do not know the reason those memory stats do not hint a potential existence of the memory leak. And how can use MemStats to show a potential memory leak?

this is only scratching the surface. Think about it, your sample programs detects memory usage is now 1Mb more than 1 hour ago. How do you decide if this is a leak, or normal memory usage ? I find that to be the hard part.

Also, the runtime.MemStats appraoch cuases your program to perform more work. It could be better if you simply query the operating system in a terminal, or have a separate program altogether, to do this monitoring.

You need to post your code. Perhaps the compiler realizes this stuff is no longer used and does not actually store it.