Possible Memory Leak - ColdFusion 2023 + Java 17.0.12

[davecordes]

Ever since we upgraded from ColdFusion 2021 to ColdFusion 2023 we have been dealing with out of memory issues. ColdFusion will run fine for roughly 24-30 hours, then we will start seeing CPU spikes to 100% every 30 seconds. Garbage collection can't free up enough memory so ColdFusion eventually crashes and we have to restart the server.

Things we have tried that don't seem to help:

- Downgrading to 17.0.11

- Tweaking the min and max heap sizes

- Tweaking the caching settings

- Changing the garbage collector algorithm to G1GC

- Tweaking our websites to cache queries for a shorter period of time (1 hour down to 15 minutes down to 5 minutes)

Here are our current settings:

Min Heap: 8192

Max Heap: 8192

Garbage Collector: UseParallelGC

Cached Templates: 1000

Cached Queries: 5000

We do have Fusion Reactor installed on all of our servers but this is like trying to find a needle in a haystack. I really don't know what I should be looking at.

Here is a most recent screenshot from 2 days ago that shows the ventual demise on one of our servers.

I am really at my wit's end here. If this isn't a memory leak I don't know what the heck it is. If anyone has any recommendations on what to try next I would appreciate it.

[BKBK]

Thanks, @xfreeman89x 

[rakesh_2359]

The issue you are pointing out does not seem to be a simple GC tuning issue. This could  strongly suggest sustained memory pressure or a memory leak.  As you explain, I can see that there is a common pattern of running fine for 24–30 hours, followed by periodic CPU spikes, heavy GC activity, and also OOM. This pattern typically means that memory is being retained and the GC cannot reclaim it.

Since heap and GC tuning have not helped, the issue is likely related to metaspace, classloader leaks, or native/off-heap memory.  The practical next step would be to enable GC logs and Native Memory Tracking, and compare memory usage shortly after startup versus just before failure. It's like a memory leak or resource retention issue, and it’s unlikely to be resolved through GC or heap tuning alone. For a deeper understanding of common signs of a Java memory leak, identifying memory leaks by analyzing a heap dump, check out this blog, From Symptoms to Solutions: Troubleshooting Java Memory Leaks &OutOfMemoryError.